%! Adobe PostScript(tm) via Sun Microsystems PC-NFS % %!PS-Adobe-2.0 ExitServer %%Title: Microsoft Word Driver Prolog %%Creator: Microsoft %%CreationDate: Fri Aug 18 1988 %%BeginDocument: Microsoft Word 5.0 0 %%msinifile: POSTSCRP %%EndComments %%BeginExitServer: 0 % userdict /msinifile known % {msinifile (POSTSCRP) eq {stop} if} if % serverdict begin 0 exitserver userdict /msorigstate known {msorigstate restore} if save /msorigstate exch def /msinifile (POSTSCRP) def %%EndExitServer %%BeginFont: mslinedraw /mslinedraw 25 dict def /PSl {msdict begin /ptop 612 def /sw 0 def /ftsz 12 def /smode 0 def /STh -3.6 def /fs 0 def /offset 0 def fonttable 1 get fontset E 90 rotate 0 -612 translate save statusdict begin /waittimeout 360 def end} def /PSp {msdict begin /ptop 792 def /sw 0 def /ftsz 12 def /smode 0 def /STh -3.6 def /fs 0 def /offset 0 def fonttable 1 get fontset E save statusdict begin /waittimeout 360 def end} def mslinedraw begin /FontType 3 def /FontMatrix [1.0 30.0 div 0 0 1.0 30.0 div 0 0] def /FontBBox [0 -8 18 30] def /Encoding 256 array def 0 1 255 {Encoding exch /.notdef put} for Encoding 45 [ /sp /sh /sh /light /med /dark /sv /srj /sdjr /dsjr /sdtr /dstr /djr /dv /dtr /dbr /sdbr /dsbr /str /sbl /sjb /sjt /sjl /sh /sjc /sdjl /dsjl /dbl /dtl /djb /djt /djl /dh /djc /dsjb /sdjb /dsjt /sdjt /sdbl /dsbl /dstl /sdtl /sdjc /dsjc /sbr /stl /black /bb /bl /br /bt] putinterval /a {moveto lineto stroke} bind def /b {moveto lineto lineto stroke} bind def /c {moveto 9 7 lineto stroke} bind def /d {moveto lineto lineto} bind def /e {lineto closepath fill} bind def /f {7 30 7 9 0 9 b} def /g {12 30 12 9 18 9 b} def /h {7 -8 7 5 0 5 b} def /i {12 -8 12 5 18 5 b} def /j {0 7 18 7 a} def /k {9 22 9 -8 a} def /l {0 5 18 5 a 0 9 18 9 a} def /m {7 22 7 -8 a 12 22 12 -8 a} def /n {0 -8 18 -8 18 22 d 0 22 e} def /CharProcs 55 dict def CharProcs begin /.notdef {} def /sp { 1 1 moveto } def /sv {k} def /srj {k 0 7 c} def /sdjr {k 0 5 9 5 a 0 9 9 9 a} def /dsjr {m 0 7 7 7 a} def /sdtr {0 7 12 7 12 -8 b 7 7 7 -8 a} def /dstr {0 9 9 9 9 -8 b 0 5 9 5 a} def /djr {f h 12 -8 12 22 a} def /dv {m} def /dtr {h 0 9 12 9 12 -8 b} def /dbr {f 0 5 12 5 12 30 b} def /sdbr {0 7 12 7 12 30 b 7 7 7 30 a} def /dsbr {0 5 9 5 9 30 b 0 9 9 9 a} def /str {0 7 9 7 9 -8 b} def /sbl {9 30 9 7 18 7 b} def /sjb {j 9 30 c} def /sjt {j 9 -8 c} def /sjl {k 18 7 c} def /sh {j} def /sjc {j k} def /sdjl {k 9 9 18 9 a 9 5 18 5 a} def /dsjl {m 12 7 18 7 a} def /dbl {g 7 30 7 5 18 5 b} def /dtl {i 7 -8 7 9 18 9 b} def /djb {f g 0 5 18 5 a} def /djt {h i 0 9 18 9 a} def /djl {g i 7 -8 7 22 a} def /dh {l} def /djc {f g h i} def /dsjb {l 9 30 9 9 a} def /sdjb {j 7 7 7 30 a 12 7 12 30 a} def /dsjt {l 9 -8 9 5 a} def /sdjt {j 7 7 7 -8 a 12 7 12 -8 a} def /sdbl {7 30 7 7 18 7 b 12 30 12 7 a} def /dsbl {9 30 9 5 18 5 b 9 9 18 9 a} def /dstl {9 -8 9 9 18 9 b 9 5 18 5 a} def /sdtl {7 -8 7 7 18 7 b 12 -8 12 7 a} def /sdjc {m j} def /dsjc {l k} def /sbr {0 7 9 7 9 30 b} def /stl {9 -8 9 7 18 7 b} def /light {0.90 setgray n} def /med {0.60 setgray n} def /dark {0.30 setgray n} def /black {n} def /bt {0 7 18 7 18 22 d 0 22 e} def /bb {0 -8 18 -8 18 7 d 0 7 e} def /bl {0 -8 9 -8 9 22 d 0 22 e} def /br {9 -8 18 -8 18 22 d 9 22 e} def end %CharProcs /BuildChar { fs 1 and 0 eq {1} {3} ifelse setlinewidth 18 0 setcharwidth exch begin Encoding exch get CharProcs exch get exec end } def end %mslinedraw %%EndFont %%BeginProcSet: msdict 1.0 0 /msdict 100 dict def FontDirectory /LineDraw known not {/LineDraw mslinedraw definefont pop} if msdict begin /SLL {/LL def} def /P {exch msu exch msu neg ptop add moveto} bind def /S {sw 0 32 4 -1 roll widthshow} bind def /C {1 string dup 0 4 -1 roll put S} bind def /J {msu ( ) stringwidth pop sub /sw exch def} bind def /PE {showpage ptop exch restore save exch /ptop exch def} bind def /SFL {msu /ptop exch def} bind def %%BeginModelCheck statusdict begin product (OmniLaser) eq { end /B1 {statusdict begin 0 setpapertray end} def /B2 {statusdict begin 1 setpapertray end} def }{ end /B1 {statusdict begin 1 setpapertray end} def /B2 {statusdict begin 2 setpapertray end} def } ifelse %%EndModelCheck /MB {statusdict begin /manualfeed true store end} def /ME {statusdict begin /manualfeed false store end} def /B {fs 2 and 0 eq {Bft} {BIft} ifelse ftsz scalefont setfont fs 1 or /fs exch def} bind def /E {Eft ftsz scalefont setfont /fs 0 def} bind def /I {fs 1 and 0 eq {Ift} {BIft} ifelse ftsz scalefont setfont fs 2 or /fs exch def} bind def /BI {BIft ftsz scalefont setfont fs 2 or 1 or /fs exch def} bind def /LU {currentpoint /uy exch def /ux exch def 1 ssm} bind def /LD {currentpoint /uy exch def /ux exch def 2 ssm} bind def /LS {currentpoint /uy exch def /ux exch def 4 ssm} bind def /LL {currentpoint /uy exch def /ux exch def /ldmode exch def 8 ssm} bind def /LE {smode 1 and 0 ne {false (_) ul} if smode 2 and 0 ne {true (_) ul} if smode 4 and 0 ne {false (\352) ul} if smode 8 and 0 ne {ux uy ldot pop pop} if not smode and /smode exch def} bind def /BD {STh ssc} def /BU {STh neg ssc} def /BN {0 ssy neg rmoveto} def /F {/ftsz exch def (-) stringwidth pop 2 div neg /STh exch def /ftcd exch def 0 2 fonttable length 1 sub {dup fonttable exch get ftcd eq {1 add fonttable exch get fontset exit}{pop}ifelse }for E} bind def /msfindfont {dup FontDirectory exch known not {pop /Courier} if findfont} def /fontset {dup 0 get msfindfont /Eft exch def dup 1 get msfindfont /Bft exch def dup 2 get msfindfont /Ift exch def 3 get msfindfont /BIft exch def }def /msu {20 div} def /ssc {dup /ssy exch def 0 exch rmoveto} bind def /ssm {dup smode or /smode exch def} bind def /Cf {/Eft /Courier findfont def /Bft /Courier-Bold findfont def /Ift /Courier-Oblique findfont def /BIft /Courier-BoldOblique findfont def} def /DUL {cc true charpath pathbbox newpath exch pop 2 index 2 index moveto cx1 4 -1 roll sub dup 0 rlineto 3 1 roll exch sub 0 exch rlineto neg 0 rlineto closepath fill} bind def /ul {gsave /cc exch def currentpoint pop /cx1 exch def ux uy moveto DUL {grestore gsave ux uy 2.4 sub moveto DUL} if grestore} bind def /PSe {restore end} bind def /ldot {gsave 2 copy currentpoint /y exch def /x exch def newpath ldmode 0 eq {/offset 0 def 1 setlinewidth [1 7] 4 setdash} {ldmode 1 eq {[6 2] 6 setdash /offset STh def .2 setlinewidth} {ldmode 2 eq {[] 0 setdash /offset 1.4 def .2 setlinewidth} if} ifelse} ifelse offset sub moveto x y offset sub lineto stroke grestore} bind def /Ccs /Courier findfont /CharStrings get def % /OrigName /NewName vector ReEncodeSmall /ReEncodeSmall { %def exch findfont begin currentdict dup length dict begin { 1 index /FID ne {def} {pop pop} ifelse } forall /FontName exch def /Encoding foreignvec def currentdict dup end end /FontName get exch definefont pop } bind def /Foreign { ReEncodeSmall } def /foreignvec StandardEncoding 256 array copy def % the following are differences from StandardEncoding. % Sequential entries do not require indices: 0 [ 39/quotesingle 96/grave 128/Ccedilla/udieresis/eacute/acircumflex/adieresis /agrave/aring/ccedilla/ecircumflex/edieresis /egrave/idieresis/icircumflex/igrave/Adieresis /Aring/Eacute/ae/AE/ocircumflex /odieresis/ograve/ucircumflex/ugrave/ydieresis /Odieresis/Udieresis/cent/sterling/yen/P/florin/aacute /iacute/oacute/uacute/ntilde/Ntilde/ordfeminine /ordmasculine/questiondown/.notdef/.notdef /.notdef/.notdef/exclamdown/guillemotleft/guillemotright /Aacute/Acircumflex/Agrave/Atilde/Ecircumflex/Edieresis /Egrave/Iacute/Icircumflex/Idieresis/Igrave/Oacute /Ocircumflex/Ograve/Otilde/Uacute/Ucircumflex/Ugrave /Scaron/Ydieresis/emdash/Zcaron/.notdef/otilde/scaron/zcaron /fraction/section/currency/quotesingle/quotedblleft /guilsinglleft/guilsinglright/.notdef/.notdef/endash/dagger/daggerdbl /paragraph/quotesinglbase/quotedblbase/quotedblright /ellipsis/.notdef/grave/acute/circumflex/tilde/macron /germandbls/breve/dotaccent/dieresis/cedilla/.notdef/hungarumlaut /ogonek/caron/emdash/Lslash/Oslash/dotlessi/lslash/oslash /.notdef/.notdef/.notdef/.notdef/.notdef/atilde /.notdef/.notdef/ring/bullet/periodcentered/.notdef/.notdef /.notdef/.notdef/.notdef ] { %forall dup type /nametype eq { %ifelse dup Ccs exch known not {pop /.notdef} if foreignvec 2 index 2 index put pop 1 add }{ exch pop } ifelse } forall pop %BeginMakeForeign /Courier /Courier-F Foreign /Courier-Bold /Courier-Bold-F Foreign /Courier-Oblique /Courier-Oblique-F Foreign /Courier-BoldOblique /Courier-BoldOblique-F Foreign /Helvetica /Helvetica-F Foreign /Helvetica-Bold /Helvetica-Bold-F Foreign /Helvetica-Oblique /Helvetica-Oblique-F Foreign /Helvetica-BoldOblique /Helvetica-BoldOblique-F Foreign /AvantGarde-Book /AvantGarde-Book-F Foreign /AvantGarde-Demi /AvantGarde-Demi-F Foreign /AvantGarde-BookOblique /AvantGarde-BookOblique-F Foreign /AvantGarde-DemiOblique /AvantGarde-DemiOblique-F Foreign FontDirectory /Helvetica-Condensed known { /Helvetica-Condensed /Helvetica-Narrow-F Foreign /Helvetica-Condensed-Bold /Helvetica-Narrow-Bold-F Foreign /Helvetica-Condensed-Oblique /Helvetica-Narrow-Oblique-F Foreign /Helvetica-Condensed-BoldObl /Helvetica-Narrow-BoldOblique-F Foreign }{ /Helvetica-Narrow /Helvetica-Narrow-F Foreign /Helvetica-Narrow-Bold /Helvetica-Narrow-Bold-F Foreign /Helvetica-Narrow-Oblique /Helvetica-Narrow-Oblique-F Foreign /Helvetica-Narrow-BoldOblique /Helvetica-Narrow-BoldOblique-F Foreign } ifelse /Bookman-Light /Bookman-Light-F Foreign /Bookman-Demi /Bookman-Demi-F Foreign /Bookman-LightItalic /Bookman-LightItalic-F Foreign /Bookman-DemiItalic /Bookman-DemiItalic-F Foreign /Times-Roman /Times-Roman-F Foreign /Times-Bold /Times-Bold-F Foreign /Times-Italic /Times-Italic-F Foreign /Times-BoldItalic /Times-BoldItalic-F Foreign /NewCenturySchlbk-Roman /NewCenturySchlbk-Roman-F Foreign /NewCenturySchlbk-Bold /NewCenturySchlbk-Bold-F Foreign /NewCenturySchlbk-Italic /NewCenturySchlbk-Italic-F Foreign /NewCenturySchlbk-BoldItalic /NewCenturySchlbk-BoldItalic-F Foreign /Palatino-Roman /Palatino-Roman-F Foreign /Palatino-Bold /Palatino-Bold-F Foreign /Palatino-Italic /Palatino-Italic-F Foreign /Palatino-BoldItalic /Palatino-BoldItalic-F Foreign /ZapfChancery-MediumItalic /ZapfChancery-MediumItalic-F Foreign %EndMakeForeign /fonttable [0 [/Courier-F /Courier-Bold-F /Courier-Oblique-F /Courier-BoldOblique-F] 8 [/Helvetica-F /Helvetica-Bold-F /Helvetica-Oblique-F /Helvetica-BoldOblique-F] 9 [/AvantGarde-Book-F /AvantGarde-Demi-F /AvantGarde-BookOblique-F /AvantGarde-DemiOblique-F] 10 [/Helvetica-Narrow-F /Helvetica-Narrow-Bold-F /Helvetica-Narrow-Oblique-F /Helvetica-Narrow-BoldOblique-F] 16 [/Bookman-Light-F /Bookman-Demi-F /Bookman-LightItalic-F /Bookman-DemiItalic-F] 24 [/Times-Roman-F /Times-Bold-F /Times-Italic-F /Times-BoldItalic-F] 25 [/NewCenturySchlbk-Roman-F /NewCenturySchlbk-Bold-F /NewCenturySchlbk-Italic-F /NewCenturySchlbk-BoldItalic-F] 26 [/Palatino-Roman-F /Palatino-Bold-F /Palatino-Italic-F /Palatino-BoldItalic-F] 50 [/ZapfChancery-MediumItalic-F /ZapfChancery-MediumItalic-F /ZapfChancery-MediumItalic-F /ZapfChancery-MediumItalic-F] 56 [/Symbol /Symbol /Symbol /Symbol] 57 [/LineDraw /LineDraw /LineDraw /LineDraw] 60 [/ZapfDingbats /ZapfDingbats /ZapfDingbats /ZapfDingbats] ] def %BeginGraphicsDefs /M {moveto} def /L {lineto} def /LH {currentpoint exch pop lineto} def /LV {currentpoint pop exch lineto} def /R {3 index 1 index 1 index 5 index 5 index 1 index M L L L closepath pop pop} def /setpat {setscreen 100 div setgray} def /setgrayed {{dup mul exch dup mul add 1 exch sub} setpat} def /setbar {{pop} setpat} def /setcross {{2 copy gt {pop} {exch pop} ifelse} setpat} def /fi {1 -1 scale} def /II1 {save count /mscount exch def} def /II2 {userdict begin /showpage {} def /letter {} def /legal {} def /a4 {} def /b5 {} def /clear { {cleartomark count msdict /mscount get eq {exit} if} loop mark} def mark} def /IT {pop restore} def /IX {exch msu exch msu neg ptop add translate} def /IS {div 3 1 roll div exch scale} def save /msdictstate exch def %!PS-Adobe-2.0 PSp 15840 SFL 1440 1680 P 24 12 F (Network) S 60 J ( Working) S 60 J ( Group) S 9260 1680 P (R.A.) S 60 J ( Woodburn) S 1440 1920 P (Request) S 60 J ( For) S 60 J ( Comments) S 60 J ( 1241) S 10254 1920 P (SAIC) S 9793 2160 P (D.L.) S 60 J ( Mills) S 8545 2400 P (University) S 60 J ( of) S 60 J ( Delaware) S 9860 2640 P (July) S 60 J ( 1991) S 2697 3200 P 0 12 F 24 16 F B (A) S 80 J ( Scheme) S 80 J ( for) S 80 J ( an) S 80 J ( Internet) S 80 J ( Encapsulation) S 80 J ( Protocol:) S E 5467 3520 P B (Version) S 80 J ( 1) S E 1440 4240 P 0 12 F 24 12 F B (1.) S 60 J ( Status) S 60 J ( of) S 60 J ( this) S 60 J ( Memo) S E 2160 4720 P 0 12 F 24 12 F (This) S 60 J ( memo) S 60 J ( defines) S 60 J ( an) S 60 J ( Experimental) S 60 J ( Protocol) S 60 J ( for) S 60 J ( the) S 60 J ( Internet) S 60 J ( community.) S 60 J ( ) S 60 J ( Discussion) S 2160 4960 P (and) S 60 J ( suggestions) S 60 J ( for) S 60 J ( improvement) S 60 J ( are) S 60 J ( requested.) S 60 J ( ) S 60 J ( Please) S 60 J ( refer) S 60 J ( to) S 60 J ( the) S 60 J ( current) S 60 J ( edition) S 60 J ( of) S 60 J ( the) S 2160 5200 P ("IAB) S 60 J ( Official) S 60 J ( Protocol) S 60 J ( Standards") S 60 J ( for) S 60 J ( the) S 60 J ( standardization) S 60 J ( state) S 60 J ( and) S 60 J ( status) S 60 J ( of) S 60 J ( this) S 60 J ( protocol.) S 2160 5440 P (Distribution) S 60 J ( of) S 60 J ( this) S 60 J ( memo) S 60 J ( is) S 60 J ( unlimited.) S 1440 6160 P 0 12 F 24 12 F B (2.) S 60 J ( Glossary) S E 2160 6640 P B (Clear) S 60 J ( Datagram) S E 2520 6880 P 0 12 F 24 12 F (The) S 60 J ( unmodified) S 60 J ( IP) S 60 J ( datagram) S 60 J ( in) S 60 J ( the) S 60 J ( User) S 60 J ( Space) S 60 J ( before) S 60 J ( Encapsulation.) S 2160 7360 P 0 12 F 24 12 F B (Clear) S 60 J ( Header) S E 2520 7600 P 0 12 F 24 12 F (The) S 60 J ( header) S 60 J ( portion) S 60 J ( of) S 60 J ( the) S 60 J ( Clear) S 60 J ( Datagram) S 60 J ( before) S 60 J ( Encapsulation.) S 60 J ( ) S 60 J ( This) S 60 J ( header) S 2520 7840 P (includes) S 60 J ( the) S 60 J ( IP) S 60 J ( header) S 60 J ( and) S 60 J ( possibly) S 60 J ( part) S 60 J ( or) S 60 J ( all) S 60 J ( of) S 60 J ( the) S 60 J ( next) S 60 J ( layer) S 60 J ( protocol) S 60 J ( header,) S 60 J ( i.e.) S 2520 8080 P (the) S 60 J ( TCP) S 60 J ( header.) S 2160 8560 P 0 12 F 24 12 F B (Decapsulation) S E 2520 8800 P 0 12 F 24 12 F (The) S 60 J ( stripping) S 60 J ( of) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Header) S 60 J ( and) S 60 J ( forwarding) S 60 J ( of) S 60 J ( the) S 60 J ( Clear) S 60 J ( Datagram) S 60 J ( by) S 2520 9040 P (the) S 60 J ( Decapsulator.) S 2160 9520 P 0 12 F 24 12 F B (Decapsulator) S E 2520 9760 P 0 12 F 24 12 F (The) S 60 J ( entity) S 60 J ( responsible) S 60 J ( for) S 60 J ( receiving) S 60 J ( an) S 60 J ( Encapsulated) S 60 J ( Datagram,) S 60 J ( decapsulating) S 60 J ( it,) S 60 J ( and) S 2520 10000 P (delivering) S 60 J ( it) S 60 J ( to) S 60 J ( the) S 60 J ( destination) S 60 J ( User) S 60 J ( Space.) S 60 J ( ) S 60 J ( Delivery) S 60 J ( may) S 60 J ( be) S 60 J ( direct,) S 60 J ( or) S 60 J ( via) S 2520 10240 P (Encapsulation.) S 60 J ( ) S 60 J ( A) S 60 J ( Decapsulator) S 60 J ( may) S 60 J ( be) S 60 J ( a) S 60 J ( host) S 60 J ( or) S 60 J ( a) S 60 J ( gateway.) S 2160 10720 P 0 12 F 24 12 F B (Encapsulated) S 60 J ( Datagram) S E 2520 10960 P 0 12 F 24 12 F (The) S 60 J ( datagram) S 60 J ( consisting) S 60 J ( of) S 60 J ( a) S 60 J ( Clear) S 60 J ( Datagram) S 60 J ( prepended) S 60 J ( with) S 60 J ( an) S 60 J ( Encapsulation) S 2520 11200 P (Header.) S 2160 11680 P 0 12 F 24 12 F B (Encapsulation) S E 2520 11920 P 0 12 F 24 12 F (The) S 60 J ( process) S 60 J ( of) S 60 J ( mapping) S 60 J ( a) S 60 J ( Clear) S 60 J ( Datagram) S 60 J ( to) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Space,) S 60 J ( prepending) S 60 J ( an) S 2520 12160 P (Encapsulation) S 60 J ( Header) S 60 J ( to) S 60 J ( the) S 60 J ( Clear) S 60 J ( Datagram) S 60 J ( and) S 60 J ( routing) S 60 J ( the) S 60 J ( Encapsulated) S 60 J ( Datagram) S 2520 12400 P (to) S 60 J ( a) S 60 J ( Decapsulator.) S 2160 12880 P 0 12 F 24 12 F B (Encapsulation) S 60 J ( Header) S E 2520 13120 P 0 12 F 24 12 F (The) S 60 J ( header) S 60 J ( for) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Protocol) S 60 J ( prepended) S 60 J ( to) S 60 J ( the) S 60 J ( Clear) S 60 J ( Datagram) S 60 J ( during) S 2520 13360 P (Encapsulation.) S 60 J ( ) S 60 J ( This) S 60 J ( header) S 60 J ( consists) S 60 J ( of) S 60 J ( an) S 60 J ( IP) S 60 J ( header) S 60 J ( followed) S 60 J ( by) S 60 J ( an) S 60 J ( Encapsulation) S 2520 13600 P (Protocol) S 60 J ( Header.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10153 14640 P (Page) S 60 J ( ) S (1) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 2160 2160 P 0 12 F 24 12 F B (Encapsulation) S 60 J ( Protocol) S 60 J ( Header) S E 2520 2400 P 0 12 F 24 12 F (The) S 60 J ( Encapsulation) S 60 J ( Protocol) S 60 J ( specific) S 60 J ( portion) S 60 J ( of) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Header.) S 2160 2880 P 0 12 F 24 12 F B (Encapsulation) S 60 J ( Space) S E 2520 3120 P 0 12 F 24 12 F (The) S 60 J ( address) S 60 J ( and) S 60 J ( routing) S 60 J ( space) S 60 J ( within) S 60 J ( which) S 60 J ( the) S 60 J ( Encapsulators) S 60 J ( and) S 60 J ( Decapsulators) S 2520 3360 P (reside.) S 60 J ( ) S 60 J ( Routing) S 60 J ( within) S 60 J ( this) S 60 J ( space) S 60 J ( is) S 60 J ( accomplished) S 60 J ( via) S 60 J ( Flows.) S 60 J ( ) S 60 J ( Encapsulation) S 60 J ( Spaces) S 2520 3600 P (do) S 60 J ( not) S 60 J ( overlap,) S 60 J ( that) S 60 J ( is,) S 60 J ( the) S 60 J ( address) S 60 J ( of) S 60 J ( any) S 60 J ( Encapsulator) S 60 J ( or) S 60 J ( Decapsulator) S 60 J ( is) S 60 J ( unique) S 60 J ( for) S 2520 3840 P (all) S 60 J ( Encapsulation) S 60 J ( Spaces.) S 2160 4320 P 0 12 F 24 12 F B (Encapsulator) S E 2520 4560 P 0 12 F 24 12 F (The) S 60 J ( entity) S 60 J ( responsible) S 60 J ( for) S 60 J ( mapping) S 60 J ( a) S 60 J ( given) S 60 J ( User) S 60 J ( Space) S 60 J ( datagram) S 60 J ( to) S 60 J ( the) S 60 J ( Encapsulation) S 2520 4800 P (Space,) S 60 J ( encapsulating) S 60 J ( the) S 60 J ( datagram,) S 60 J ( and) S 60 J ( forwarding) S 60 J ( the) S 60 J ( Encapsulated) S 60 J ( Datagram) S 60 J ( to) S 60 J ( a) S 2520 5040 P (Decapsulator.) S 60 J ( ) S 60 J ( An) S 60 J ( Encapsulator) S 60 J ( may) S 60 J ( be) S 60 J ( a) S 60 J ( host) S 60 J ( or) S 60 J ( a) S 60 J ( gateway.) S 2160 5520 P 0 12 F 24 12 F B (Flow) S E 2520 5760 P 0 12 F 24 12 F (Also) S 60 J ( called) S 60 J ( a) S 60 J ( "tunnel.") S 60 J ( ) S 60 J ( A) S 60 J ( flow) S 60 J ( is) S 60 J ( the) S 60 J ( end-to-end) S 60 J ( path) S 60 J ( in) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Space) S 60 J ( over) S 2520 6000 P (which) S 60 J ( Encapsulated) S 60 J ( Datagrams) S 60 J ( travel.) S 60 J ( ) S 60 J ( There) S 60 J ( may) S 60 J ( be) S 60 J ( several) S 2520 6240 P (Encapsulator/Decapsulator) S 60 J ( pairs) S 60 J ( along) S 60 J ( a) S 60 J ( given) S 60 J ( flow.) S 60 J ( ) S 60 J ( Note) S 60 J ( that) S 60 J ( a) S 60 J ( Flow) S 60 J ( does) S 60 J ( not) S 2520 6480 P (denote) S 60 J ( what) S 60 J ( User) S 60 J ( Space) S 60 J ( gateways) S 60 J ( are) S 60 J ( traversed) S 60 J ( along) S 60 J ( the) S 60 J ( path.) S 2160 6960 P 0 12 F 24 12 F B (Flow) S 60 J ( ID) S E 2520 7200 P 0 12 F 24 12 F (A) S 60 J ( 32-bit) S 60 J ( identifier) S 60 J ( which) S 60 J ( uniquely) S 60 J ( distinguishes) S 60 J ( a) S 60 J ( flow) S 60 J ( in) S 60 J ( a) S 60 J ( given) S 60 J ( Encapsulator) S 60 J ( or) S 2520 7440 P (Decapsulator.) S 60 J ( ) S 60 J ( Flow) S 60 J ( IDs) S 60 J ( are) S 60 J ( specific) S 60 J ( to) S 60 J ( a) S 60 J ( single) S 60 J ( Encapsulator/Decapsulator) S 60 J ( Entity) S 60 J ( and) S 2520 7680 P (are) S 60 J ( not) S 60 J ( global) S 60 J ( quantities.) S 2160 8160 P 0 12 F 24 12 F B (Mapping) S 60 J ( Function) S E 2520 8400 P 0 12 F 24 12 F (This) S 60 J ( is) S 60 J ( the) S 60 J ( function) S 60 J ( of) S 60 J ( mapping) S 60 J ( a) S 60 J ( Clear) S 60 J ( Header) S 60 J ( to) S 60 J ( a) S 60 J ( particular) S 60 J ( Flow.) S 60 J ( ) S 60 J ( All) S 2520 8640 P (encapsulators) S 60 J ( along) S 60 J ( a) S 60 J ( given) S 60 J ( Flow) S 60 J ( are) S 60 J ( required) S 60 J ( to) S 60 J ( map) S 60 J ( a) S 60 J ( given) S 60 J ( Clear) S 60 J ( Header) S 60 J ( to) S 60 J ( the) S 2520 8880 P (same) S 60 J ( Flow.) S 2160 9360 P 0 12 F 24 12 F B (User) S 60 J ( Address) S E 2520 9600 P 0 12 F 24 12 F (The) S 60 J ( address) S 60 J ( or) S 60 J ( identifier) S 60 J ( uniquely) S 60 J ( identifying) S 60 J ( an) S 60 J ( entity) S 60 J ( within) S 60 J ( a) S 60 J ( User) S 60 J ( Space.) S 2160 10080 P 0 12 F 24 12 F B (Source) S 60 J ( Route) S E 2520 10320 P 0 12 F 24 12 F (A) S 60 J ( complete) S 60 J ( end-to-end) S 60 J ( route) S 60 J ( which) S 60 J ( is) S 60 J ( computed) S 60 J ( at) S 60 J ( the) S 60 J ( source) S 60 J ( and) S 60 J ( enumerates) S 60 J ( transit) S 2520 10560 P (gateways.) S 2160 11040 P 0 12 F 24 12 F B (User) S 60 J ( Space) S E 2520 11280 P 0 12 F 24 12 F (The) S 60 J ( address) S 60 J ( and) S 60 J ( routing) S 60 J ( space) S 60 J ( within) S 60 J ( which) S 60 J ( the) S 60 J ( users) S 60 J ( reside.) S 60 J ( ) S 60 J ( Routing) S 60 J ( within) S 60 J ( this) S 2520 11520 P (space) S 60 J ( provides) S 60 J ( reachability) S 60 J ( between) S 60 J ( all) S 60 J ( address) S 60 J ( pairs) S 60 J ( within) S 60 J ( the) S 60 J ( space.) S 60 J ( ) S 60 J ( User) S 60 J ( Spaces) S 2520 11760 P (do) S 60 J ( not) S 60 J ( overlap,) S 60 J ( that) S 60 J ( is,) S 60 J ( a) S 60 J ( given) S 60 J ( User) S 60 J ( Address) S 60 J ( is) S 60 J ( unique) S 60 J ( in) S 60 J ( all) S 60 J ( User) S 60 J ( Spaces) S 1440 12480 P 0 12 F 24 12 F B (3.) S 60 J ( Background) S E 1440 12960 P 0 12 F 24 12 F (For) S 98 J ( several) S 98 J ( years) S 98 J ( researchers) S 98 J ( in) S 98 J ( the) S 98 J ( Internet) S 98 J ( community) S 98 J ( have) S 98 J ( needed) S 98 J ( a) S 98 J ( means) S 98 J ( of) S 98 J ( "tunneling") S 1440 13200 P (between) S 65 J ( networks.) S 66 J ( ) S 65 J ( A) S 66 J ( tunnel) S 65 J ( is) S 66 J ( essentially) S 65 J ( a) S 66 J ( Source) S 65 J ( Route) S 66 J ( that) S 65 J ( circumvents) S 65 J ( conventional) S 65 J ( routing) S 1440 13440 P (mechanisms.) S 72 J ( ) S 73 J ( Tunnels) S 72 J ( provide) S 73 J ( the) S 72 J ( means) S 73 J ( to) S 72 J ( bypass) S 72 J ( routing) S 72 J ( failures,) S 72 J ( avoid) S 72 J ( broken) S 72 J ( gateways) S 72 J ( and) S 1440 13680 P (routing) S 60 J ( domains,) S 60 J ( or) S 60 J ( establish) S 60 J ( deterministic) S 60 J ( paths) S 60 J ( for) S 60 J ( experimentation.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10153 14640 P (Page) S 60 J ( ) S (2) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1440 2160 P (There) S 155 J ( are) S 156 J ( several) S 155 J ( means) S 156 J ( of) S 155 J ( accomplishing) S 155 J ( tunneling.) S 155 J ( ) S 155 J ( In) S 155 J ( the) S 155 J ( past,) S 155 J ( tunneling) S 155 J ( has) S 155 J ( been) S 1440 2400 P (accomplished) S 97 J ( through) S 98 J ( source) S 97 J ( routing) S 98 J ( options) S 98 J ( in) S 98 J ( the) S 98 J ( IP) S 98 J ( header) S 98 J ( which) S 98 J ( allow) S 98 J ( gateways) S 98 J ( along) S 98 J ( a) S 1440 2640 P (given) S 98 J ( path) S 99 J ( to) S 98 J ( be) S 99 J ( enumerated.) S 98 J ( ) S 99 J ( The) S 98 J ( disadvantage) S 99 J ( of) S 98 J ( source) S 99 J ( routing) S 98 J ( in) S 99 J ( the) S 98 J ( IP) S 99 J ( header) S 99 J ( is) S 99 J ( that) S 99 J ( it) S 1440 2880 P (requires) S 95 J ( the) S 96 J ( source) S 95 J ( to) S 96 J ( know) S 95 J ( something) S 96 J ( about) S 95 J ( the) S 95 J ( networks) S 95 J ( traversed) S 95 J ( to) S 95 J ( reach) S 95 J ( the) S 95 J ( destination.) S 1440 3120 P (The) S 107 J ( source) S 108 J ( must) S 107 J ( then) S 108 J ( modify) S 107 J ( outgoing) S 108 J ( packets) S 107 J ( to) S 108 J ( reflect) S 107 J ( the) S 108 J ( source) S 107 J ( route.) S 108 J ( ) S 107 J ( Current) S 107 J ( routing) S 1440 3360 P (implementations) S 111 J ( generally) S 112 J ( don't) S 111 J ( support) S 112 J ( source) S 112 J ( routes) S 112 J ( in) S 112 J ( their) S 112 J ( routing) S 112 J ( tables) S 112 J ( as) S 112 J ( a) S 112 J ( means) S 112 J ( of) S 1440 3600 P (reaching) S 60 J ( an) S 60 J ( IP) S 60 J ( address,) S 60 J ( nor) S 60 J ( do) S 60 J ( current) S 60 J ( routing) S 60 J ( protocols.) S 1440 4080 P (Another) S 80 J ( means) S 81 J ( of) S 80 J ( tunneling) S 81 J ( would) S 80 J ( be) S 81 J ( to) S 80 J ( develop) S 81 J ( a) S 81 J ( new) S 81 J ( IP) S 81 J ( option.) S 81 J ( ) S 81 J ( This) S 81 J ( option) S 81 J ( field) S 81 J ( would) S 81 J ( be) S 1440 4320 P (part) S 85 J ( of) S 86 J ( a) S 85 J ( separate) S 85 J ( IP) S 85 J ( header) S 85 J ( that) S 85 J ( could) S 85 J ( be) S 85 J ( prepended) S 85 J ( to) S 85 J ( an) S 85 J ( IP) S 85 J ( datagram.) S 85 J ( ) S 85 J ( The) S 85 J ( IP) S 85 J ( option) S 85 J ( would) S 1440 4560 P (indicate) S 70 J ( information) S 71 J ( about) S 70 J ( the) S 71 J ( original) S 70 J ( datagram.) S 71 J ( ) S 70 J ( This) S 71 J ( tunneling) S 70 J ( option) S 70 J ( has) S 70 J ( the) S 70 J ( disadvantage) S 70 J ( of) S 1440 4800 P (significantly) S 66 J ( modifying) S 67 J ( existing) S 66 J ( IP) S 67 J ( implementations) S 66 J ( to) S 67 J ( handle) S 66 J ( a) S 67 J ( new) S 66 J ( IP) S 67 J ( option.) S 66 J ( ) S 67 J ( It) S 66 J ( also) S 67 J ( would) S 66 J ( be) S 1440 5040 P (less) S 70 J ( flexible) S 71 J ( in) S 70 J ( permitting) S 71 J ( the) S 70 J ( tunneling) S 71 J ( of) S 70 J ( other) S 71 J ( protocols,) S 70 J ( such) S 71 J ( as) S 70 J ( ISO) S 71 J ( protocols,) S 71 J ( through) S 71 J ( an) S 71 J ( IP) S 1440 5280 P (environment.) S 76 J ( ) S 77 J ( An) S 76 J ( even) S 77 J ( less) S 76 J ( palatable) S 77 J ( alternative) S 76 J ( would) S 76 J ( be) S 76 J ( to) S 76 J ( replace) S 76 J ( IP) S 76 J ( with) S 76 J ( a) S 76 J ( new) S 76 J ( networking) S 1440 5520 P (protocol) S 60 J ( or) S 60 J ( a) S 60 J ( new) S 60 J ( version) S 60 J ( of) S 60 J ( IP) S 60 J ( with) S 60 J ( tunneling) S 60 J ( built) S 60 J ( in) S 60 J ( as) S 60 J ( part) S 60 J ( of) S 60 J ( its) S 60 J ( functionality.) S 1440 6000 P (A) S 71 J ( final) S 71 J ( alternative) S 71 J ( is) S 71 J ( to) S 71 J ( create) S 71 J ( a) S 71 J ( new) S 71 J ( IP) S 71 J ( encapsulation) S 71 J ( protocol) S 71 J ( which) S 71 J ( uses) S 71 J ( the) S 71 J ( current) S 71 J ( IP) S 71 J ( header) S 1440 6240 P (format.) S 84 J ( ) S 85 J ( By) S 84 J ( using) S 85 J ( encapsulation,) S 84 J ( a) S 85 J ( destination) S 84 J ( can) S 85 J ( be) S 84 J ( reached) S 84 J ( transparently) S 84 J ( without) S 84 J ( the) S 84 J ( source) S 1440 6480 P (having) S 134 J ( to) S 135 J ( know) S 134 J ( topology) S 135 J ( specifics.) S 134 J ( ) S 135 J ( Virtual) S 134 J ( networks) S 135 J ( can) S 134 J ( be) S 134 J ( created) S 134 J ( by) S 134 J ( tying) S 134 J ( otherwise) S 1440 6720 P (unconnected) S 60 J ( machines) S 60 J ( together) S 60 J ( with) S 60 J ( flows) S 60 J ( through) S 60 J ( an) S 60 J ( encapsulation) S 60 J ( space.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10153 14640 P (Page) S 60 J ( ) S (3) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1080 1920 P II1 1080 9201 IX 10080 12960 7281 9360 IS 0 15840 IX II2 %%BeginDocument: RFC-FIG1.EPS %!PS-Adobe-2.0 EPSF-1.2 %%Title: RFC-FIG1.EPS %%Creator: Freelance Plus 3.01 %%CreationDate: 1/16/1991 %%Pages: 1 %%DocumentFonts: (atend) %%BoundingBox: 0 0 648 468 %%EndComments %%BeginProcSet: Freelance Plus /Freelance_Plus dup 100 dict def load begin [ ] {bind} stopped { (patching the bind operator...) = flush /*bind /bind load def /bind { dup xcheck { *bind } if } *bind def } if pop /bdf {bind def} bind def /ldf {load def} bdf /mt /moveto ldf /rt /rmoveto ldf /l2 /lineto ldf /c2 /curveto ldf /sg /setgray ldf /gs /gsave ldf /ef /eofill ldf /rl2 /rlineto ldf /st /stroke ldf /gr /grestore ldf /np /newpath ldf /sv /save ldf /su /statusdict ldf /rs /restore 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(Space B) show 4667 4681 itr mt -488 0 itr rt 0 57 itr rt (Encapsulation) show 4666 4505 itr mt -301 0 itr rt 0 57 itr rt (Space C) show 6210 1277 itr mt -484 0 itr rt 0 57 itr rt (User Space D) show rs end %%Trailer %%DocumentFonts: Helvetica-Oblique %%EndDocument end IT 4061 9681 P (Fig.) S 60 J ( 1.) S 60 J ( ) S 60 J ( Encapsulation) S 60 J ( Architectural) S 60 J ( Model) S 1440 10161 P (Up) S 83 J ( until) S 84 J ( now,) S 83 J ( there) S 84 J ( has) S 83 J ( been) S 84 J ( no) S 83 J ( standard) S 84 J ( for) S 84 J ( an) S 84 J ( encapsulation) S 84 J ( protocol.) S 84 J ( ) S 84 J ( This) S 84 J ( RFC) S 84 J ( provides) S 84 J ( a) S 1440 10401 P (means) S 60 J ( of) S 60 J ( performing) S 60 J ( encapsulation) S 60 J ( in) S 60 J ( the) S 60 J ( Internet) S 60 J ( environment.) S 1440 11121 P 0 12 F 24 12 F B (4.) S 60 J ( Architecture) S 60 J ( and) S 60 J ( Approach) S E 1440 11601 P 0 12 F 24 12 F (The) S 165 J ( architecture) S 166 J ( for) S 165 J ( encapsulation) S 166 J ( is) S 165 J ( based) S 166 J ( on) S 165 J ( two) S 166 J ( entities) S 165 J ( --) S 166 J ( an) S 165 J ( Encapsulator) S 165 J ( and) S 165 J ( a) S 1440 11841 P (Decapsulator.) S 60 J ( ) S 60 J ( These) S 60 J ( entities) S 60 J ( and) S 60 J ( the) S 60 J ( associated) S 60 J ( spaces) S 60 J ( are) S 60 J ( shown) S 60 J ( in) S 60 J ( Fig.) S 60 J ( 1.) S 1440 12321 P (Encapsulators) S 94 J ( and) S 95 J ( Decapsulators) S 94 J ( have) S 95 J ( addresses) S 94 J ( in) S 95 J ( the) S 94 J ( User) S 95 J ( Spaces) S 94 J ( to) S 95 J ( which) S 94 J ( they) S 94 J ( belong,) S 94 J ( as) S 1440 12561 P (well) S 117 J ( as) S 118 J ( addresses) S 117 J ( in) S 118 J ( the) S 118 J ( Encapsulation) S 118 J ( Spaces) S 118 J ( to) S 118 J ( which) S 118 J ( they) S 118 J ( belong.) S 118 J ( An) S 118 J ( encapsulator) S 118 J ( will) S 1440 12801 P (receive) S 79 J ( a) S 80 J ( Clear) S 79 J ( Datagram) S 80 J ( from) S 79 J ( its) S 80 J ( User) S 79 J ( Space,) S 80 J ( and) S 79 J ( after) S 80 J ( determining) S 80 J ( that) S 80 J ( encapsulation) S 80 J ( should) S 1440 13041 P (be) S 82 J ( used,) S 83 J ( perform) S 82 J ( a) S 83 J ( mapping) S 82 J ( function) S 83 J ( which) S 82 J ( translates) S 83 J ( the) S 82 J ( User) S 83 J ( Space) S 83 J ( information) S 83 J ( in) S 83 J ( the) S 83 J ( Clear) S 1440 13281 P (Header) S 76 J ( to) S 77 J ( an) S 76 J ( Encapsulation) S 77 J ( Header.) S 77 J ( ) S 77 J ( This) S 77 J ( Encapsulation) S 77 J ( Header) S 77 J ( is) S 77 J ( then) S 77 J ( prepended) S 77 J ( to) S 77 J ( the) S 77 J ( Clear) S 1440 13521 P (Datagram) S 70 J ( to) S 71 J ( form) S 71 J ( the) S 71 J ( Encapsulated) S 71 J ( Datagram,) S 71 J ( as) S 71 J ( in) S 71 J ( Fig) S 71 J ( 2.) S 71 J ( ) S 71 J ( It) S 71 J ( is) S 71 J ( desirable) S 71 J ( that) S 71 J ( the) S 71 J ( encapsulation) S 1440 13761 P (process) S 101 J ( be) S 102 J ( transparent) S 101 J ( to) S 102 J ( entities) S 101 J ( in) S 102 J ( the) S 101 J ( User) S 101 J ( Space.) S 101 J ( ) S 101 J ( Only) S 101 J ( the) S 101 J ( Encapsulator) S 101 J ( need) S 101 J ( know) S 101 J ( that) S 1440 14001 P (encapsulation) S 60 J ( is) S 60 J ( occurring.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10153 14640 P (Page) S 60 J ( ) S (4) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 2088 2040 P 0 12 F 57 12 F (ZDDDDDDDDDDD) S -72 J ( DBDDDDDDDDDDDDDDDD) S -72 J ( DBDDDDDDDDDBDDDDDDDDDDDDDD?) S 2304 2280 P 0 12 F 24 12 F (Encapsulating) S 877 J ( Encapsulation) S 1034 J ( Clear) S 882 J ( Remainder) S 60 J ( of) S 1368 2280 P 0 12 F 57 12 F () S 720 J ( 3) S 1656 J ( 3) S 2376 J ( 3) S 1296 J ( 3) S 2016 J ( 3) S 2304 2520 P 0 12 F 24 12 F () S 276 J ( IP) S 60 J ( Header) S 1010 J ( Proto.) S 60 J ( Header) S 962 J ( Header) S 688 J ( Clear) S 60 J ( Datagram) S 1368 2520 P 0 12 F 57 12 F () S 720 J ( 3) S 1656 J ( 3) S 2376 J ( 3) S 1296 J ( 3) S 2016 J ( 3) S 2088 2760 P (@DDDDDDDDDDD) S -72 J ( DADDDDDDDDDDDDDDDD) S -72 J ( DADDDDDDDDDADDDDDDDDDDDDDDY) S 1368 3120 P () S 720 J ( 3) S 4176 J ( 3) S 3456 J ( 3) S 2304 3360 P 0 12 F 24 12 F () S 958 J ( Encapsulation) S 60 J ( Header) S 2137 J ( Clear) S 60 J ( Datagram) S 1368 3360 P 0 12 F 57 12 F () S 720 J ( 3) S 4176 J ( 3) S 3456 J ( 3) S 1368 3600 P () S 720 J ( 3) S 4176 J ( 3) S 3456 J ( 3) S 3874 4320 P 0 12 F 24 12 F (Fig.) S 60 J ( 2.) S 60 J ( ) S 60 J ( Example) S 60 J ( of) S 60 J ( an) S 60 J ( Encapsulated) S 60 J ( Datagram) S 1440 4800 P (The) S 82 J ( Encapsulator) S 83 J ( forwards) S 82 J ( the) S 83 J ( datagram) S 82 J ( to) S 83 J ( a) S 82 J ( Decapsulator) S 82 J ( whose) S 82 J ( identity) S 82 J ( is) S 82 J ( determined) S 82 J ( at) S 82 J ( the) S 1440 5040 P (time) S 78 J ( of) S 79 J ( encapsulation.) S 78 J ( ) S 79 J ( The) S 78 J ( Decapsulator) S 79 J ( receives) S 78 J ( the) S 79 J ( Encapsulated) S 78 J ( Datagram) S 79 J ( and) S 78 J ( removes) S 78 J ( the) S 1440 5280 P (Encapsulation) S 130 J ( Header) S 131 J ( and) S 130 J ( treats) S 130 J ( the) S 130 J ( Clear) S 130 J ( Datagram) S 130 J ( as) S 130 J ( if) S 130 J ( it) S 130 J ( were) S 130 J ( received) S 130 J ( locally.) S 130 J ( ) S 130 J ( The) S 1440 5520 P (requirement) S 84 J ( for) S 85 J ( the) S 84 J ( address) S 85 J ( of) S 84 J ( the) S 85 J ( Decapsulator) S 84 J ( is) S 85 J ( that) S 85 J ( it) S 85 J ( be) S 85 J ( reachable) S 85 J ( from) S 85 J ( the) S 85 J ( Encapsulator's) S 1440 5760 P (Encapsulation) S 60 J ( Space) S 60 J ( address.) S 1440 6480 P 0 12 F 24 12 F B (5.) S 60 J ( Generation) S 60 J ( of) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Header) S E 1440 6960 P 0 12 F 24 12 F (The) S 66 J ( contents) S 67 J ( of) S 66 J ( the) S 67 J ( Encapsulation) S 67 J ( Header) S 67 J ( are) S 67 J ( generated) S 67 J ( by) S 67 J ( performing) S 67 J ( a) S 67 J ( mapping) S 67 J ( function) S 67 J ( from) S 1440 7200 P (the) S 63 J ( Clear) S 64 J ( Header) S 63 J ( to) S 64 J ( the) S 63 J ( contents) S 64 J ( of) S 63 J ( the) S 64 J ( Encapsulation) S 63 J ( Header.) S 64 J ( ) S 64 J ( This) S 64 J ( mapping) S 64 J ( function) S 64 J ( could) S 64 J ( take) S 1440 7440 P (many) S 99 J ( forms,) S 100 J ( but) S 100 J ( the) S 100 J ( end) S 100 J ( result) S 100 J ( should) S 100 J ( be) S 100 J ( the) S 100 J ( same.) S 100 J ( ) S 100 J ( The) S 100 J ( following) S 100 J ( paragraphs) S 100 J ( describe) S 100 J ( one) S 1440 7680 P (method) S 60 J ( of) S 60 J ( performing) S 60 J ( the) S 60 J ( mapping.) S 60 J ( ) S 60 J ( The) S 60 J ( process) S 60 J ( is) S 60 J ( illustrated) S 60 J ( in) S 60 J ( Fig.) S 60 J ( 3.) S 1440 8160 P (In) S 83 J ( the) S 84 J ( first) S 83 J ( part) S 84 J ( of) S 83 J ( the) S 83 J ( mapping) S 83 J ( function,) S 83 J ( the) S 83 J ( Clear) S 83 J ( Header) S 83 J ( is) S 83 J ( matched) S 83 J ( with) S 83 J ( stored) S 83 J ( headers) S 83 J ( and) S 1440 8400 P (masks) S 69 J ( to) S 70 J ( determine) S 69 J ( a) S 70 J ( Flow) S 69 J ( ID.) S 70 J ( ) S 69 J ( This) S 70 J ( is) S 69 J ( essentially) S 70 J ( a) S 70 J ( "mask-and-match") S 70 J ( table) S 70 J ( look) S 70 J ( up,) S 70 J ( where) S 70 J ( the) S 1440 8640 P (lookup) S 79 J ( table) S 80 J ( holds) S 79 J ( three) S 80 J ( entries,) S 79 J ( a) S 80 J ( Clear) S 79 J ( Header,) S 80 J ( a) S 79 J ( header) S 80 J ( mask,) S 79 J ( and) S 80 J ( a) S 79 J ( corresponding) S 80 J ( Flow) S 79 J ( ID.) S 1440 8880 P (The) S 63 J ( mask) S 64 J ( can) S 63 J ( be) S 64 J ( used) S 63 J ( for) S 64 J ( allowing) S 63 J ( a) S 64 J ( range) S 63 J ( of) S 63 J ( source) S 63 J ( and) S 63 J ( destination) S 63 J ( addresses) S 63 J ( to) S 63 J ( map) S 63 J ( to) S 63 J ( a) S 63 J ( given) S 1440 9120 P (flow.) S 66 J ( ) S 67 J ( Other) S 66 J ( fields,) S 67 J ( such) S 66 J ( as) S 67 J ( the) S 66 J ( IP) S 67 J ( TOS) S 66 J ( bits) S 67 J ( or) S 66 J ( even) S 67 J ( the) S 66 J ( TCP) S 67 J ( source) S 66 J ( or) S 66 J ( destination) S 66 J ( port) S 66 J ( addresses) S 1440 9360 P (could) S 70 J ( also) S 71 J ( be) S 70 J ( used) S 71 J ( to) S 70 J ( discriminate) S 71 J ( between) S 70 J ( Flows.) S 71 J ( ) S 70 J ( This) S 70 J ( flexibility) S 70 J ( allows) S 70 J ( many) S 70 J ( possibilities) S 70 J ( for) S 1440 9600 P (using) S 70 J ( the) S 71 J ( mapping) S 70 J ( function.) S 71 J ( ) S 70 J ( Not) S 71 J ( only) S 70 J ( can) S 71 J ( a) S 70 J ( given) S 70 J ( network) S 70 J ( be) S 70 J ( associated) S 70 J ( with) S 70 J ( a) S 70 J ( particular) S 70 J ( flow,) S 1440 9840 P (but) S 60 J ( even) S 60 J ( a) S 60 J ( particular) S 60 J ( TCP) S 60 J ( protocol) S 60 J ( or) S 60 J ( connection) S 60 J ( could) S 60 J ( be) S 60 J ( distinguished) S 60 J ( from) S 60 J ( another.) S 1440 10320 P (How) S 70 J ( the) S 71 J ( lookup) S 70 J ( table) S 71 J ( is) S 70 J ( built) S 71 J ( and) S 70 J ( maintained) S 71 J ( is) S 70 J ( not) S 71 J ( part) S 70 J ( of) S 71 J ( this) S 70 J ( protocol.) S 71 J ( ) S 70 J ( It) S 71 J ( is) S 70 J ( assumed) S 71 J ( that) S 70 J ( it) S 71 J ( is) S 1440 10560 P (managed) S 80 J ( by) S 81 J ( some) S 80 J ( higher) S 81 J ( layer) S 80 J ( entity.) S 81 J ( ) S 80 J ( It) S 81 J ( would) S 80 J ( be) S 81 J ( sufficient) S 80 J ( to) S 81 J ( configure) S 80 J ( the) S 81 J ( tables) S 81 J ( from) S 81 J ( ascii) S 1440 10800 P (text) S 60 J ( files) S 60 J ( if) S 60 J ( necessary.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10153 14640 P (Page) S 60 J ( ) S (5) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1080 1920 P II1 1080 6329 IX 10080 13580 4409 5940 IS 0 15840 IX II2 %%BeginDocument: RFC-FIG3.EPS %!PS-Adobe-2.0 EPSF-1.2 %%Title: RFC-FIG3.EPS %%Creator: Freelance Plus 3.01 %%CreationDate: 1/16/1991 %%Pages: 1 %%DocumentFonts: (atend) %%BoundingBox: 0 0 679 297 %%EndComments %%BeginProcSet: Freelance Plus /Freelance_Plus dup 100 dict def load begin [ ] {bind} stopped { (patching the bind operator...) = flush /*bind /bind load def /bind { dup xcheck { *bind } if } *bind def } if pop /bdf {bind def} bind def /ldf {load def} bdf /mt /moveto ldf /rt /rmoveto ldf /l2 /lineto ldf /c2 /curveto ldf /sg /setgray ldf /gs /gsave ldf /ef /eofill ldf /rl2 /rlineto ldf /st /stroke ldf /gr /grestore ldf /np /newpath ldf /sv /save ldf /su /statusdict ldf /rs /restore ldf /sw /setlinewidth ldf /sd /setdash ldf /cp /closepath ldf /ed {exch def } bdf /cfnt {findfont exch makefont setfont} bdf /itr {transform round exch round exch itransform} bdf /fres 72 0 matrix currentmatrix dtransform exch dup mul exch dup mul add sqrt def /res fres def /mcm matrix currentmatrix bdf %%EndProcSet end %%EndProlog %%BeginSetup Freelance_Plus begin save newpath .1 .1 scale /ecm matrix currentmatrix bdf /sem {ecm setmatrix} bdf -91 -91 translate 2 setlinecap 0 setlinejoin 1.42 setmiterlimit%%EndSetup 0.000 sg 6 sw sv np [] 0 sd 1826 932 itr mt 2725 932 itr l2 2725 1607 itr l2 1826 1607 itr l2 1826 932 itr l2 cp st rs sv np 3187 1157 itr mt 3636 1157 itr l2 3636 1382 itr l2 3187 1382 itr l2 3187 1157 itr l2 cp st rs sv np 4086 1591 itr mt 4772 1591 itr l2 4772 2747 itr l2 4086 2747 itr l2 4086 1591 itr l2 cp st rs sv np 5222 467 itr mt 6358 467 itr l2 6358 1157 itr l2 5222 1157 itr l2 5222 467 itr l2 cp st rs sv np 1139 1271 itr mt 1655 1271 itr l2 st rs sv np 1826 1271 itr mt 1655 1313 itr l2 1655 1228 itr l2 1826 1271 itr l2 gs 0.100 sg ef gr cp st rs sv np 1364 1271 itr mt 1364 709 itr l2 5052 709 itr l2 st rs sv np 5222 709 itr mt 5052 751 itr l2 5052 666 itr l2 5222 709 itr l2 gs 0.100 sg ef gr cp st rs sv np 2725 1271 itr mt 3017 1271 itr l2 st rs sv np 3187 1271 itr mt 3017 1313 itr l2 3017 1228 itr l2 3187 1271 itr l2 gs 0.100 sg ef gr cp st rs sv np 3636 1271 itr mt 3861 1271 itr l2 3861 2282 itr l2 3915 2282 itr l2 st rs sv np 4085 2282 itr mt 3915 2324 itr l2 3915 2239 itr l2 4085 2282 itr l2 gs 0.100 sg ef gr cp st rs sv np 4772 2282 itr mt 4997 2282 itr l2 4997 933 itr l2 5052 933 itr l2 st rs sv np 5222 933 itr mt 5052 976 itr l2 5052 891 itr l2 5222 933 itr l2 gs 0.100 sg ef gr cp st rs /Ich 256 array def StandardEncoding Ich copy pop /bullet/paragraph/section/dieresis/tilde/ring /circumflex/grave/acute/quotedblleft/quotesingle /ellipsis/endash/emdash/guilsinglleft/guilsinglright /quotedblbase/quotesinglbase/quotedblright/OE/oe 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bfn findfont def /nf bfd maxlength 4 add dict def bfd{exch dup dup /FID ne exch /Encoding ne and {exch nf 3 1 roll put}{pop pop} ifelse }forall nf/FontName nfn put nf/Encoding ncs put nf/PaintType 2 put nf/StrokeWidth lnw put nfn nf definefont pop}bdf /IencSO { /nfn ed /bfn ed /lnw ed /bfd bfn findfont def /nf bfd maxlength 4 add dict def bfd{exch dup /FID ne { exch nf 3 1 roll put}{pop pop} ifelse }forall nf/FontName nfn put nf/PaintType 2 put nf/StrokeWidth lnw put nfn nf definefont pop}bdf /Helvetica-Oblique /Flfon6 Ienc [153 0 0.00 153 -15 -113] /Flfon6 cfnt 812 1357 itr mt -190 0 itr rt 0 57 itr rt (Clear) show 807 1181 itr mt -258 0 itr rt 0 57 itr rt (Header) show 2285 1439 itr mt -190 0 itr rt 0 57 itr rt (Mask) show 2280 1262 itr mt -58 0 itr rt 0 57 itr rt (&) show 2284 1085 itr mt -216 0 itr rt 0 57 itr rt (Match) show [115 0 0.00 115 -11 -85] /Flfon6 cfnt 3424 1264 itr mt -200 0 itr rt 0 43 itr rt (Flow ID) show [153 0 0.00 153 -15 -113] /Flfon6 cfnt 4427 2290 itr mt -246 0 itr rt 0 57 itr rt (Encap.) show 4428 2113 itr mt -157 0 itr rt 0 57 itr rt (Info.) show 4425 1936 itr mt -198 0 itr rt 0 57 itr rt (Table) show 5795 909 itr mt -488 0 itr rt 0 57 itr rt (Encapsulation) show 5801 732 itr mt -258 0 itr rt 0 57 itr rt (Header) show 3238 572 itr mt -411 0 itr rt 0 57 itr rt (Some Clear) show 3232 395 itr mt -429 0 itr rt 0 57 itr rt (Header Info.) show rs end %%Trailer %%DocumentFonts: Helvetica-Oblique %%EndDocument end IT 3821 6809 P (Fig.) S 60 J ( 3.) S 60 J ( ) S 60 J ( Generation) S 60 J ( of) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Header) S 1440 7289 P (The) S 95 J ( Flow) S 96 J ( IDs) S 95 J ( are) S 96 J ( managed) S 95 J ( at) S 96 J ( a) S 95 J ( higher) S 96 J ( layer) S 95 J ( as) S 96 J ( well.) S 95 J ( ) S 96 J ( An) S 95 J ( example) S 96 J ( of) S 95 J ( how) S 96 J ( Flow) S 95 J ( IDs) S 96 J ( can) S 95 J ( be) S 1440 7529 P (managed) S 81 J ( is) S 82 J ( found) S 81 J ( in) S 82 J ( the) S 81 J ( Setup) S 82 J ( protocol) S 81 J ( of) S 82 J ( the) S 81 J ( Inter-Domain) S 82 J ( Policy) S 81 J ( Sensitive) S 81 J ( Routing) S 81 J ( Protocol) S 1440 7769 P (\(IDPR\).) S 101 J ( [4]) S 102 J ( ) S 101 J ( The) S 102 J ( upper) S 101 J ( layer) S 102 J ( protocol) S 101 J ( would) S 102 J ( be) S 101 J ( responsible) S 102 J ( for) S 101 J ( maintaining) S 102 J ( information) S 101 J ( not) S 1440 8009 P (carried) S 96 J ( in) S 97 J ( the) S 96 J ( encapsulation) S 97 J ( protocol) S 96 J ( related) S 97 J ( to) S 96 J ( the) S 97 J ( flow.) S 97 J ( ) S 97 J ( This) S 97 J ( could) S 97 J ( include) S 97 J ( the) S 97 J ( information) S 1440 8249 P (necessary) S 79 J ( to) S 80 J ( construct) S 79 J ( the) S 80 J ( Encapsulation) S 79 J ( Header) S 80 J ( \(described) S 79 J ( below\)) S 79 J ( as) S 79 J ( well) S 79 J ( as) S 79 J ( information) S 79 J ( such) S 1440 8489 P (as) S 147 J ( the) S 148 J ( type) S 147 J ( of) S 148 J ( data) S 147 J ( being) S 148 J ( encapsulated) S 147 J ( \(currently) S 148 J ( only) S 147 J ( IP) S 148 J ( is) S 147 J ( defined\),) S 148 J ( and) S 147 J ( the) S 147 J ( type) S 147 J ( of) S 1440 8729 P (authentication) S 71 J ( used) S 72 J ( if) S 71 J ( any.) S 72 J ( ) S 71 J ( Note) S 71 J ( that) S 71 J ( IDPR) S 71 J ( Setup) S 71 J ( requires) S 71 J ( the) S 71 J ( use) S 71 J ( of) S 71 J ( a) S 71 J ( longer) S 71 J ( Flow) S 71 J ( ID) S 71 J ( which) S 71 J ( is) S 1440 8969 P (unique) S 60 J ( for) S 60 J ( the) S 60 J ( entire) S 60 J ( universe) S 60 J ( of) S 60 J ( Encapsulators) S 60 J ( and) S 60 J ( is) S 60 J ( the) S 60 J ( same) S 60 J ( at) S 60 J ( every) S 60 J ( Encapsulator.) S 1440 9449 P (The) S 74 J ( Flow) S 75 J ( ID) S 74 J ( that) S 75 J ( results) S 74 J ( from) S 75 J ( the) S 74 J ( mapping) S 75 J ( of) S 74 J ( a) S 75 J ( Clear) S 74 J ( Header) S 74 J ( is) S 74 J ( a) S 74 J ( 32) S 74 J ( bit) S 74 J ( quantity) S 74 J ( and) S 74 J ( identifies) S 1440 9689 P (the) S 104 J ( Flow) S 105 J ( as) S 105 J ( it) S 105 J ( is) S 105 J ( seen) S 105 J ( by) S 105 J ( the) S 105 J ( Encapsulator.) S 105 J ( ) S 105 J ( If) S 105 J ( a) S 105 J ( Clear) S 105 J ( Datagram) S 105 J ( must) S 105 J ( be) S 105 J ( encapsulated) S 105 J ( and) S 1440 9929 P (decapsulated) S 77 J ( several) S 78 J ( times) S 77 J ( in) S 78 J ( order) S 78 J ( reach) S 78 J ( the) S 78 J ( destination,) S 78 J ( the) S 78 J ( Flow) S 78 J ( ID) S 78 J ( may) S 78 J ( be) S 78 J ( different) S 78 J ( at) S 78 J ( each) S 1440 10169 P (Encapsulator,) S 101 J ( but) S 102 J ( need) S 101 J ( not) S 102 J ( be.) S 101 J ( ) S 102 J ( The) S 101 J ( Flow) S 102 J ( ID) S 101 J ( acts) S 102 J ( as) S 101 J ( an) S 102 J ( index) S 101 J ( into) S 102 J ( a) S 101 J ( table) S 101 J ( of) S 101 J ( Encapsulation) S 1440 10409 P (Header) S 91 J ( information) S 92 J ( that) S 91 J ( is) S 92 J ( used) S 91 J ( to) S 92 J ( build) S 91 J ( the) S 92 J ( Encapsulation) S 91 J ( Header.) S 91 J ( ) S 91 J ( Note) S 91 J ( that) S 91 J ( the) S 91 J ( decision) S 91 J ( to) S 1440 10649 P (make) S 72 J ( the) S 73 J ( Flow) S 72 J ( ID) S 73 J ( local) S 72 J ( to) S 73 J ( the) S 72 J ( Encapsulator) S 73 J ( is) S 72 J ( due) S 73 J ( to) S 72 J ( the) S 73 J ( difficulty) S 73 J ( in) S 73 J ( choosing) S 73 J ( and) S 73 J ( maintaining) S 1440 10889 P (globally) S 60 J ( unique) S 60 J ( identifiers.) S 1440 11369 P (The) S 62 J ( intermediate) S 63 J ( step) S 63 J ( of) S 63 J ( using) S 63 J ( a) S 63 J ( Flow) S 63 J ( ID) S 63 J ( entirely) S 63 J ( optional.) S 63 J ( ) S 63 J ( The) S 63 J ( important) S 63 J ( requirement) S 63 J ( is) S 63 J ( that) S 63 J ( all) S 1440 11609 P (Encapsulators) S 104 J ( along) S 105 J ( a) S 104 J ( Flow) S 105 J ( map) S 104 J ( the) S 105 J ( same) S 104 J ( Clear) S 105 J ( Header) S 104 J ( to) S 105 J ( the) S 104 J ( same) S 104 J ( Flow) S 104 J ( \(which) S 104 J ( could) S 104 J ( be) S 1440 11849 P (identified) S 87 J ( by) S 87 J ( different) S 87 J ( identifiers) S 87 J ( along) S 87 J ( the) S 87 J ( way\).) S 87 J ( ) S 87 J ( However,) S 87 J ( by) S 87 J ( allowing) S 87 J ( for) S 87 J ( a) S 87 J ( Flow) S 87 J ( ID) S 87 J ( in) S 87 J ( the) S 1440 12089 P (protocol,) S 90 J ( a) S 91 J ( more) S 90 J ( efficient) S 91 J ( implementation) S 90 J ( of) S 91 J ( the) S 90 J ( mapping) S 91 J ( function) S 90 J ( becomes) S 91 J ( possible.) S 90 J ( ) S 90 J ( This) S 90 J ( is) S 1440 12329 P (discussed) S 60 J ( in) S 60 J ( more) S 60 J ( detail) S 60 J ( when) S 60 J ( we) S 60 J ( consider) S 60 J ( the) S 60 J ( Decapsulator.) S 1440 12809 P (The) S 60 J ( following) S 60 J ( information) S 60 J ( is) S 60 J ( required) S 60 J ( to) S 60 J ( construct) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Header:) S 2160 13289 P 0 12 F 24 12 F B (Flow) S 60 J ( ID) S E 2520 13529 P 0 12 F 24 12 F (This) S 60 J ( is) S 60 J ( the) S 60 J ( key) S 60 J ( for) S 60 J ( this) S 60 J ( table) S 60 J ( of) S 60 J ( information) S 60 J ( and) S 60 J ( represents) S 60 J ( the) S 60 J ( Flow) S 60 J ( ID) S 60 J ( relative) S 60 J ( to) S 60 J ( the) S 2520 13769 P (current) S 60 J ( Encapsulator.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10153 14640 P (Page) S 60 J ( ) S (6) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 2160 2160 P 0 12 F 24 12 F B (Decapsulator) S 60 J ( Address) S E 2520 2400 P 0 12 F 24 12 F (The) S 60 J ( IP) S 60 J ( address) S 60 J ( of) S 60 J ( the) S 60 J ( Decapsulator) S 60 J ( in) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Space) S 60 J ( must) S 60 J ( be) S 60 J ( known) S 60 J ( to) S 2520 2640 P (build) S 60 J ( the) S 60 J ( IP) S 60 J ( portion) S 60 J ( of) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Header.) S 2160 3120 P 0 12 F 24 12 F B (Decapsulator's) S 60 J ( Flow) S 60 J ( ID) S E 2520 3360 P 0 12 F 24 12 F (The) S 60 J ( Flow) S 60 J ( ID,) S 60 J ( if) S 60 J ( any,) S 60 J ( for) S 60 J ( the) S 60 J ( Flow) S 60 J ( as) S 60 J ( seen) S 60 J ( by) S 60 J ( the) S 60 J ( Decapsulator) S 60 J ( must) S 60 J ( be) S 60 J ( known.) S 2160 3840 P 0 12 F 24 12 F B (Previous) S 60 J ( Encapsulator's) S 60 J ( Address) S E 2520 4080 P 0 12 F 24 12 F (If) S 60 J ( this) S 60 J ( is) S 60 J ( not) S 60 J ( the) S 60 J ( first) S 60 J ( Encapsulator) S 60 J ( along) S 60 J ( the) S 60 J ( Flow,) S 60 J ( the) S 60 J ( previous) S 60 J ( Encapsulator's) S 2520 4320 P (address) S 60 J ( must) S 60 J ( be) S 60 J ( known) S 60 J ( for) S 60 J ( error) S 60 J ( reporting.) S 2160 4800 P 0 12 F 24 12 F B (Previous) S 60 J ( Encapsulator's) S 60 J ( Flow) S 60 J ( ID) S E 2520 5040 P 0 12 F 24 12 F (In) S 60 J ( addition) S 60 J ( to) S 60 J ( the) S 60 J ( previous) S 60 J ( Encapsulator's) S 60 J ( address,) S 60 J ( the) S 60 J ( Flow) S 60 J ( ID) S 60 J ( of) S 60 J ( the) S 60 J ( Flow) S 60 J ( relative) S 60 J ( to) S 2520 5280 P (the) S 60 J ( previous) S 60 J ( Encapsulator) S 60 J ( must) S 60 J ( be) S 60 J ( known.) S 1440 5760 P (The) S 61 J ( Encapsulation) S 62 J ( Header) S 61 J ( consists) S 62 J ( of) S 61 J ( an) S 62 J ( IP) S 62 J ( Header) S 62 J ( as) S 62 J ( well) S 62 J ( as) S 62 J ( an) S 62 J ( Encapsulation) S 62 J ( Protocol) S 62 J ( Header.) S 1440 6000 P (The) S 89 J ( two) S 90 J ( pieces) S 89 J ( of) S 90 J ( information) S 89 J ( required) S 90 J ( for) S 89 J ( the) S 90 J ( Encapsulation) S 89 J ( Protocol) S 90 J ( Header) S 89 J ( which) S 90 J ( must) S 90 J ( be) S 1440 6240 P (determined) S 93 J ( at) S 94 J ( the) S 93 J ( time) S 94 J ( of) S 93 J ( encapsulation) S 94 J ( are) S 93 J ( the) S 94 J ( protocol) S 93 J ( which) S 94 J ( is) S 93 J ( being) S 93 J ( encapsulated) S 93 J ( and) S 93 J ( the) S 1440 6480 P (Flow) S 60 J ( ID) S 60 J ( to) S 60 J ( send) S 60 J ( to) S 60 J ( the) S 60 J ( Decapsulator.) S 60 J ( ) S 60 J ( The) S 60 J ( generation) S 60 J ( of) S 60 J ( the) S 60 J ( IP) S 60 J ( header) S 60 J ( is) S 60 J ( more) S 60 J ( complicated.) S 1440 6960 P (There) S 60 J ( are) S 60 J ( two) S 60 J ( possible) S 60 J ( ways) S 60 J ( each) S 60 J ( field) S 60 J ( in) S 60 J ( the) S 60 J ( Clear) S 60 J ( Header) S 60 J ( could) S 60 J ( related) S 60 J ( to) S 60 J ( the) S 60 J ( new) S 60 J ( IP) S 60 J ( header.) S 2160 7440 P 0 12 F 24 12 F B (Copy) S E 2520 7680 P 0 12 F 24 12 F (Copy) S 60 J ( the) S 60 J ( existing) S 60 J ( field) S 60 J ( from) S 60 J ( the) S 60 J ( Clear) S 60 J ( Header) S 60 J ( to) S 60 J ( the) S 60 J ( IP) S 60 J ( header) S 60 J ( in) S 60 J ( the) S 60 J ( Encapsulation) S 2520 7920 P (Header.) S 2160 8400 P 0 12 F 24 12 F B (Ignore) S E 2520 8640 P 0 12 F 24 12 F (The) S 60 J ( field) S 60 J ( may) S 60 J ( or) S 60 J ( may) S 60 J ( not) S 60 J ( have) S 60 J ( existed) S 60 J ( in) S 60 J ( the) S 60 J ( Clear) S 60 J ( Header,) S 60 J ( but) S 60 J ( does) S 60 J ( not) S 60 J ( apply) S 60 J ( to) S 60 J ( the) S 2520 8880 P (new) S 60 J ( IP) S 60 J ( header.) S 1440 9360 P (The) S 92 J ( IP) S 93 J ( header) S 92 J ( has) S 93 J ( a) S 92 J ( fixed) S 93 J ( portion) S 93 J ( and) S 93 J ( a) S 93 J ( variable) S 93 J ( portion,) S 93 J ( the) S 93 J ( options) S 93 J ( list.) S 93 J ( ) S 93 J ( A) S 93 J ( summary) S 93 J ( of) S 93 J ( all) S 1440 9600 P (possible) S 60 J ( IP) S 60 J ( fields) S 60 J ( and) S 60 J ( the) S 60 J ( relation) S 60 J ( to) S 60 J ( the) S 60 J ( Clear) S 60 J ( Header) S 60 J ( follows) S 60 J ( in) S 60 J ( Table) S 60 J ( 1.) S 60 J ( [2]) S 1440 10080 P (Note) S 76 J ( that) S 77 J ( most) S 76 J ( of) S 77 J ( the) S 77 J ( fields) S 77 J ( in) S 77 J ( the) S 77 J ( Clear) S 77 J ( Header) S 77 J ( are) S 77 J ( simply) S 77 J ( ignored.) S 77 J ( ) S 77 J ( Fields) S 77 J ( such) S 77 J ( as) S 77 J ( the) S 77 J ( Header) S 1440 10320 P (Length) S 91 J ( in) S 92 J ( the) S 91 J ( Clear) S 92 J ( Header) S 91 J ( have) S 92 J ( no) S 91 J ( effect) S 92 J ( on) S 91 J ( the) S 92 J ( Header) S 91 J ( Length) S 92 J ( of) S 92 J ( the) S 92 J ( new) S 92 J ( IP) S 92 J ( header.) S 92 J ( ) S 92 J ( The) S 1440 10560 P (fields) S 60 J ( which) S 60 J ( are) S 60 J ( more) S 60 J ( interesting) S 60 J ( and) S 60 J ( require) S 60 J ( some) S 60 J ( thought) S 60 J ( are) S 60 J ( now) S 60 J ( discussed.) S 1440 11040 P (The) S 71 J ( Quality) S 72 J ( of) S 71 J ( Service) S 72 J ( bits) S 71 J ( should) S 72 J ( be) S 71 J ( copied) S 72 J ( from) S 71 J ( the) S 72 J ( Clear) S 72 J ( Header) S 72 J ( to) S 72 J ( the) S 72 J ( new) S 72 J ( IP) S 72 J ( header.) S 72 J ( ) S 72 J ( This) S 1440 11280 P (is) S 111 J ( in) S 112 J ( keeping) S 111 J ( with) S 112 J ( the) S 111 J ( transparency) S 112 J ( principle) S 111 J ( that) S 112 J ( if) S 111 J ( the) S 112 J ( User) S 111 J ( Space) S 112 J ( was) S 111 J ( providing) S 111 J ( a) S 111 J ( given) S 1440 11520 P (service,) S 60 J ( then) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Space) S 60 J ( must) S 60 J ( provide) S 60 J ( the) S 60 J ( same) S 60 J ( service..) S 1440 12000 P (The) S 88 J ( More) S 89 J ( Fragments) S 88 J ( bit) S 89 J ( and) S 88 J ( Fragment) S 89 J ( Offset) S 88 J ( should) S 89 J ( not) S 88 J ( be) S 89 J ( copied,) S 88 J ( since) S 89 J ( the) S 88 J ( datagram) S 88 J ( being) S 1440 12240 P (built) S 110 J ( is) S 111 J ( a) S 110 J ( complete) S 111 J ( datagram,) S 110 J ( regardless) S 111 J ( of) S 110 J ( the) S 111 J ( status) S 110 J ( of) S 111 J ( the) S 110 J ( encapsulated) S 110 J ( datagram.) S 110 J ( ) S 110 J ( If) S 110 J ( the) S 1440 12480 P (completed) S 82 J ( datagram) S 83 J ( is) S 82 J ( too) S 83 J ( large) S 82 J ( for) S 83 J ( the) S 82 J ( interface,) S 83 J ( it) S 82 J ( will) S 82 J ( be) S 82 J ( fragmented) S 82 J ( for) S 82 J ( transmission) S 82 J ( to) S 82 J ( the) S 1440 12720 P (decapsulator) S 60 J ( by) S 60 J ( the) S 60 J ( normal) S 60 J ( IP) S 60 J ( fragmentation) S 60 J ( mechanism.) S 1440 13200 P (The) S 77 J ( Don't) S 78 J ( Fragment) S 77 J ( bit) S 78 J ( should) S 77 J ( not) S 78 J ( be) S 77 J ( copied) S 78 J ( into) S 77 J ( the) S 78 J ( Encapsulation) S 78 J ( Header.) S 78 J ( ) S 78 J ( The) S 78 J ( transparency) S 1440 13440 P (principle) S 116 J ( would) S 117 J ( again) S 116 J ( be) S 117 J ( violated.) S 116 J ( ) S 117 J ( It) S 116 J ( should) S 116 J ( be) S 116 J ( up) S 116 J ( to) S 116 J ( the) S 116 J ( Encapsulator) S 116 J ( to) S 116 J ( decide) S 116 J ( whether) S 1440 13680 P (fragmentation) S 67 J ( should) S 68 J ( be) S 67 J ( allowed) S 68 J ( across) S 67 J ( the) S 68 J ( Encapsulation) S 67 J ( Space.) S 68 J ( ) S 67 J ( If) S 67 J ( it) S 67 J ( is) S 67 J ( decided) S 67 J ( that) S 67 J ( the) S 67 J ( DF) S 67 J ( bit) S 1440 13920 P (should) S 83 J ( be) S 83 J ( used,) S 83 J ( then) S 83 J ( ICMP) S 83 J ( message) S 83 J ( would) S 83 J ( be) S 83 J ( returned) S 83 J ( if) S 83 J ( the) S 83 J ( Encapsulated) S 83 J ( Datagram) S 83 J ( required) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10153 14640 P (Page) S 60 J ( ) S (7) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1440 2160 P (fragmentation) S 77 J ( across) S 77 J ( the) S 77 J ( Encapsulation) S 77 J ( Space) S 77 J ( ) S 77 J ( The) S 77 J ( mechanism) S 77 J ( for) S 77 J ( returning) S 77 J ( an) S 77 J ( ICMP) S 77 J ( message) S 1440 2400 P (to) S 81 J ( the) S 82 J ( source) S 81 J ( in) S 82 J ( the) S 81 J ( User) S 82 J ( space) S 81 J ( will) S 82 J ( have) S 82 J ( to) S 82 J ( be) S 82 J ( modified,) S 82 J ( however,) S 82 J ( and) S 82 J ( this) S 82 J ( is) S 82 J ( discussed) S 82 J ( in) S 82 J ( the) S 1440 2640 P (Appendix) S 60 J ( B.) S 1440 3120 P (Regarding) S 79 J ( the) S 80 J ( Time) S 79 J ( To) S 80 J ( Live) S 79 J ( \(TTL\)) S 80 J ( field,) S 79 J ( the) S 80 J ( easiest) S 79 J ( thing) S 80 J ( to) S 79 J ( do) S 80 J ( is) S 80 J ( to) S 80 J ( ignore) S 80 J ( the) S 80 J ( TTL) S 80 J ( from) S 80 J ( the) S 1440 3360 P (Clear) S 74 J ( Header.) S 75 J ( ) S 74 J ( If) S 75 J ( this) S 74 J ( field) S 75 J ( were) S 74 J ( copied) S 75 J ( from) S 74 J ( the) S 74 J ( Clear) S 74 J ( Header) S 74 J ( to) S 74 J ( the) S 74 J ( new) S 74 J ( IP) S 74 J ( header,) S 74 J ( the) S 74 J ( packet) S 1440 3600 P (life) S 81 J ( might) S 82 J ( be) S 81 J ( prematurely) S 82 J ( exceeded) S 81 J ( during) S 82 J ( transit) S 81 J ( in) S 82 J ( the) S 81 J ( Encapsulation) S 82 J ( Space.) S 81 J ( ) S 82 J ( This) S 81 J ( breaks) S 82 J ( the) S 1440 3840 P (transparency) S 63 J ( rule) S 64 J ( of) S 63 J ( encapsulation) S 64 J ( as) S 63 J ( seen) S 64 J ( from) S 63 J ( the) S 64 J ( User) S 63 J ( Space.) S 64 J ( ) S 63 J ( The) S 64 J ( TTL) S 63 J ( of) S 63 J ( the) S 63 J ( Clear) S 63 J ( Header) S 63 J ( is) S 1440 4080 P (decremented) S 103 J ( before) S 104 J ( encapsulation) S 103 J ( by) S 104 J ( the) S 103 J ( IP) S 104 J ( forwarding) S 103 J ( function,) S 104 J ( so) S 103 J ( there) S 104 J ( is) S 104 J ( no) S 104 J ( chance) S 104 J ( of) S 104 J ( a) S 1440 4320 P (packet) S 60 J ( looping) S 60 J ( forever) S 60 J ( if) S 60 J ( the) S 60 J ( links) S 60 J ( of) S 60 J ( a) S 60 J ( Flow) S 60 J ( form) S 60 J ( a) S 60 J ( loop.) S 3888 4680 P 0 12 F 57 12 F (ZDDDDDDDDDDDDDDDDDDDBDDDDDDDDD?) S 4104 4920 P 0 12 F 24 12 F () S 1049 J ( Field) S 1479 J ( Mapping) S 1368 4920 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 3888 5160 P (CDDDDDDDDDDDDDDDDDDDEDDDDDDDDD4) S 4104 5400 P 0 12 F 24 12 F () S 216 J ( Version) S 2120 J ( Ignore) S 1368 5400 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 5640 P 0 12 F 24 12 F () S 216 J ( Header) S 60 J ( Length) S 1445 J ( Ignore) S 1368 5640 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 5880 P 0 12 F 24 12 F () S 216 J ( Precedence) S 1785 J ( Copy) S 1368 5880 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 6120 P 0 12 F 24 12 F () S 216 J ( QoS) S 60 J ( bits) S 2047 J ( Copy) S 1368 6120 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 6360 P 0 12 F 24 12 F () S 216 J ( Total) S 60 J ( Length) S 1631 J ( Ignore) S 1368 6360 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 6600 P 0 12 F 24 12 F () S 216 J ( Identification) S 1584 J ( Ignore) S 1368 6600 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 6840 P 0 12 F 24 12 F () S 216 J ( Don't) S 60 J ( Fragment) S 60 J ( Bit) S 1022 J ( Ignore) S 1368 6840 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 7080 P 0 12 F 24 12 F () S 216 J ( More) S 60 J ( Fragments) S 60 J ( Bit) S 932 J ( Ignore) S 1368 7080 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 7320 P 0 12 F 24 12 F () S 216 J ( Fragment) S 60 J ( Offset) S 1299 J ( Ignore) S 1368 7320 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 7560 P 0 12 F 24 12 F () S 216 J ( Time) S 60 J ( to) S 60 J ( Live) S 1624 J ( Ignore) S 1368 7560 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 7800 P 0 12 F 24 12 F () S 216 J ( Protocol) S 2066 J ( Ignore) S 1368 7800 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 8040 P 0 12 F 24 12 F () S 216 J ( Header) S 60 J ( Checksum) S 1112 J ( Ignore) S 1368 8040 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 8280 P 0 12 F 24 12 F () S 216 J ( Source) S 60 J ( Address) S 1367 J ( Ignore) S 1368 8280 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 8520 P 0 12 F 24 12 F () S 216 J ( Destination) S 60 J ( Address) S 926 J ( Ignore) S 1368 8520 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 8760 P 0 12 F 24 12 F () S 216 J ( End) S 60 J ( of) S 60 J ( Option) S 60 J ( List) S 1072 J ( Ignore) S 1368 8760 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 9000 P 0 12 F 24 12 F () S 216 J ( NOP) S 60 J ( Option) S 1674 J ( Ignore) S 1368 9000 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 9240 P 0 12 F 24 12 F () S 216 J ( Security) S 60 J ( Option) S 1352 J ( Copy) S 1368 9240 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 9480 P 0 12 F 24 12 F () S 216 J ( LSR) S 60 J ( Option) S 1713 J ( Ignore) S 1368 9480 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 9720 P 0 12 F 24 12 F () S 216 J ( SSR) S 60 J ( Option) S 1727 J ( Ignore) S 1368 9720 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 9960 P 0 12 F 24 12 F () S 216 J ( RR) S 60 J ( Option) S 1833 J ( Ignore) S 1368 9960 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 10200 P 0 12 F 24 12 F () S 216 J ( Stream) S 60 J ( ID) S 60 J ( Option) S 1159 J ( Ignore) S 1368 10200 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 4104 10440 P 0 12 F 24 12 F () S 216 J ( Timestamp) S 60 J ( Option) S 1071 J ( Ignore) S 1368 10440 P 0 12 F 57 12 F () S 2520 J ( 3) S 2736 J ( 3) S 1296 J ( 3) S 3888 10680 P (@DDDDDDDDDDDDDDDDDDDADDDDDDDDDY) S 4045 11040 P 0 12 F 24 12 F (Table) S 60 J ( 1.) S 60 J ( ) S 60 J ( Summary) S 60 J ( of) S 60 J ( IP) S 60 J ( Header) S 60 J ( Mappings) S 1440 11520 P (The) S 111 J ( protocol) S 112 J ( field) S 112 J ( for) S 112 J ( the) S 112 J ( new) S 112 J ( IP) S 112 J ( header) S 112 J ( should) S 112 J ( be) S 112 J ( filled) S 112 J ( with) S 112 J ( the) S 112 J ( protocol) S 112 J ( number) S 112 J ( of) S 112 J ( the) S 1440 11760 P (encapsulation) S 60 J ( protocol.) S 1440 12240 P (The) S 100 J ( source) S 101 J ( address) S 100 J ( in) S 101 J ( the) S 100 J ( new) S 101 J ( IP) S 100 J ( header) S 101 J ( becomes) S 100 J ( the) S 101 J ( IP) S 100 J ( address) S 101 J ( of) S 100 J ( the) S 100 J ( Encapsulator) S 100 J ( in) S 100 J ( the) S 1440 12480 P (Encapsulation) S 75 J ( Domain.) S 76 J ( ) S 75 J ( The) S 76 J ( destination) S 75 J ( address) S 76 J ( becomes) S 76 J ( the) S 76 J ( IP) S 76 J ( address) S 76 J ( of) S 76 J ( the) S 76 J ( Decapsulator) S 76 J ( as) S 1440 12720 P (found) S 60 J ( in) S 60 J ( the) S 60 J ( encapsulation) S 60 J ( table.) S 1440 13200 P (IP) S 121 J ( Options) S 122 J ( are) S 121 J ( generally) S 122 J ( not) S 122 J ( copied) S 122 J ( because) S 122 J ( most) S 122 J ( don't) S 122 J ( make) S 122 J ( sense) S 122 J ( in) S 122 J ( the) S 122 J ( context) S 122 J ( of) S 122 J ( the) S 1440 13440 P (Encapsulation) S 121 J ( Space,) S 122 J ( as) S 121 J ( the) S 122 J ( transparency) S 121 J ( principle) S 122 J ( would) S 121 J ( indicate.) S 122 J ( ) S 121 J ( The) S 121 J ( security) S 121 J ( option) S 121 J ( is) S 1440 13680 P (probably) S 78 J ( the) S 79 J ( one) S 78 J ( option) S 79 J ( that) S 78 J ( should) S 79 J ( get) S 78 J ( copied) S 79 J ( for) S 78 J ( the) S 79 J ( same) S 78 J ( reason) S 79 J ( QOS) S 78 J ( and) S 79 J ( precedence) S 79 J ( fields) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10153 14640 P (Page) S 60 J ( ) S (8) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1440 2160 P (are) S 109 J ( copied,) S 110 J ( the) S 109 J ( Encapsulation) S 110 J ( Space) S 109 J ( must) S 110 J ( provide) S 109 J ( the) S 110 J ( expected) S 109 J ( service.) S 110 J ( ) S 110 J ( Timestamp,) S 110 J ( Loose) S 1440 2400 P (Source) S 60 J ( Route,) S 60 J ( Strict) S 60 J ( Source) S 60 J ( Route,) S 60 J ( and) S 60 J ( Record) S 60 J ( Route) S 60 J ( are) S 60 J ( not) S 60 J ( copied) S 60 J ( during) S 60 J ( encapsulation.) S 1440 3120 P 0 12 F 24 12 F B (6.) S 60 J ( Decapsulation) S E 1440 3600 P 0 12 F 24 12 F (In) S 144 J ( the) S 145 J ( ideal) S 144 J ( situation,) S 145 J ( a) S 144 J ( Decapsulator) S 145 J ( receives) S 144 J ( an) S 145 J ( Encapsulated) S 145 J ( Datagram,) S 145 J ( strips) S 145 J ( off) S 145 J ( the) S 1440 3840 P (Encapsulation) S 86 J ( Header) S 87 J ( and) S 86 J ( sends) S 87 J ( the) S 86 J ( Clear) S 87 J ( Datagram) S 86 J ( back) S 87 J ( into) S 86 J ( IP) S 87 J ( so) S 86 J ( that) S 87 J ( it) S 86 J ( is) S 87 J ( forwarded) S 87 J ( from) S 1440 4080 P (that) S 73 J ( point.) S 74 J ( ) S 74 J ( However,) S 74 J ( if) S 74 J ( the) S 74 J ( Clear) S 74 J ( Datagram) S 74 J ( has) S 74 J ( not) S 74 J ( reached) S 74 J ( the) S 74 J ( destination) S 74 J ( User) S 74 J ( Space,) S 74 J ( it) S 74 J ( must) S 1440 4320 P (again) S 96 J ( be) S 97 J ( encapsulated) S 97 J ( to) S 97 J ( move) S 97 J ( it) S 97 J ( close) S 97 J ( to) S 97 J ( the) S 97 J ( destination) S 97 J ( User) S 97 J ( Space.) S 97 J ( ) S 97 J ( In) S 97 J ( this) S 97 J ( latter) S 97 J ( case) S 97 J ( the) S 1440 4560 P (Decapsulator) S 137 J ( would) S 138 J ( become) S 137 J ( an) S 138 J ( Encapsulator) S 137 J ( and) S 138 J ( would) S 137 J ( perform) S 137 J ( the) S 137 J ( same) S 137 J ( calculation) S 137 J ( to) S 1440 4800 P (generate) S 106 J ( the) S 107 J ( Encapsulation) S 106 J ( Header) S 107 J ( as) S 106 J ( did) S 107 J ( the) S 106 J ( previous) S 107 J ( Encapsulator.) S 106 J ( ) S 107 J ( In) S 106 J ( order) S 107 J ( to) S 106 J ( make) S 106 J ( this) S 1440 5040 P (process) S 60 J ( more) S 60 J ( efficient,) S 60 J ( the) S 60 J ( use) S 60 J ( of) S 60 J ( Flow) S 60 J ( IDs) S 60 J ( have) S 60 J ( been) S 60 J ( incorporated) S 60 J ( into) S 60 J ( the) S 60 J ( protocol.) S 1440 5520 P (When) S 87 J ( Flow) S 88 J ( IDs) S 87 J ( are) S 88 J ( used,) S 87 J ( the) S 87 J ( Flow) S 87 J ( ID) S 87 J ( received) S 87 J ( in) S 87 J ( the) S 87 J ( Encapsulation) S 87 J ( Header) S 87 J ( corresponds) S 87 J ( to) S 87 J ( a) S 1440 5760 P (stored) S 74 J ( Flow) S 75 J ( ID) S 74 J ( in) S 75 J ( the) S 74 J ( Decapsulator.) S 75 J ( ) S 74 J ( At) S 74 J ( this) S 74 J ( point) S 74 J ( the) S 74 J ( Decapsulator) S 74 J ( has) S 74 J ( the) S 74 J ( option) S 74 J ( of) S 74 J ( bypassing) S 1440 6000 P (the) S 71 J ( mask) S 72 J ( and) S 71 J ( match) S 72 J ( operation) S 71 J ( on) S 72 J ( the) S 71 J ( Clear) S 72 J ( Header.) S 71 J ( ) S 72 J ( The) S 71 J ( received) S 72 J ( Flow) S 72 J ( ID) S 72 J ( can) S 72 J ( be) S 72 J ( used) S 72 J ( to) S 72 J ( point) S 1440 6240 P (directly) S 68 J ( into) S 69 J ( the) S 68 J ( local) S 69 J ( Encapsulator) S 68 J ( tables) S 69 J ( for) S 68 J ( the) S 68 J ( construction) S 68 J ( of) S 68 J ( the) S 68 J ( next) S 68 J ( Encapsulation) S 68 J ( Header.) S 1440 6480 P (If) S 83 J ( the) S 84 J ( Flow) S 84 J ( ID) S 84 J ( is) S 84 J ( unknown,) S 84 J ( an) S 84 J ( error) S 84 J ( message) S 84 J ( is) S 84 J ( sent) S 84 J ( back) S 84 J ( to) S 84 J ( the) S 84 J ( previous) S 84 J ( Encapsulator) S 84 J ( to) S 84 J ( that) S 1440 6720 P (effect) S 60 J ( and) S 60 J ( a) S 60 J ( signal) S 60 J ( is) S 60 J ( sent) S 60 J ( to) S 60 J ( upper) S 60 J ( layer) S 60 J ( entity) S 60 J ( managing) S 60 J ( the) S 60 J ( encapsulation) S 60 J ( tables.) S 1440 7200 P (Because) S 114 J ( the) S 114 J ( normal) S 114 J ( IP) S 114 J ( forwarding) S 114 J ( mechanism) S 114 J ( is) S 114 J ( being) S 114 J ( bypassed) S 114 J ( when) S 114 J ( Flow) S 114 J ( IDs) S 114 J ( are) S 114 J ( used,) S 1440 7440 P (certain) S 85 J ( mechanisms) S 86 J ( normally) S 86 J ( handled) S 86 J ( by) S 86 J ( IP) S 86 J ( must) S 86 J ( be) S 86 J ( taken) S 86 J ( care) S 86 J ( of) S 86 J ( by) S 86 J ( the) S 86 J ( Decapsulator) S 86 J ( before) S 1440 7680 P (encapsulation.) S 66 J ( ) S 67 J ( The) S 66 J ( Decapsulator) S 67 J ( must) S 66 J ( decrement) S 67 J ( the) S 67 J ( TTL) S 67 J ( before) S 67 J ( the) S 67 J ( next) S 67 J ( encapsulation) S 67 J ( occurs.) S 1440 7920 P (If) S 84 J ( a) S 85 J ( Time) S 84 J ( Exceeded) S 85 J ( error) S 84 J ( occurs,) S 85 J ( then) S 84 J ( an) S 85 J ( ICMP) S 84 J ( message) S 85 J ( is) S 84 J ( sent) S 85 J ( to) S 84 J ( the) S 85 J ( source) S 84 J ( indicated) S 85 J ( in) S 85 J ( the) S 1440 8160 P (Clear) S 60 J ( Header.) S 1440 8880 P 0 12 F 24 12 F B (7.) S 60 J ( Error) S 60 J ( Messages) S E 1440 9360 P 0 12 F 24 12 F (There) S 76 J ( are) S 77 J ( two) S 76 J ( kinds) S 77 J ( of) S 76 J ( error) S 77 J ( message) S 76 J ( built) S 77 J ( into) S 76 J ( the) S 77 J ( encapsulation) S 77 J ( protocol.) S 77 J ( ) S 77 J ( The) S 77 J ( first) S 77 J ( is) S 77 J ( used) S 77 J ( to) S 1440 9600 P (report) S 75 J ( unknown) S 76 J ( flow) S 75 J ( identifiers) S 76 J ( seen) S 75 J ( by) S 75 J ( a) S 75 J ( Decapsulator) S 75 J ( and) S 75 J ( the) S 75 J ( second) S 75 J ( is) S 75 J ( for) S 75 J ( the) S 75 J ( forwarding) S 75 J ( of) S 1440 9840 P (ICMP) S 60 J ( messages.) S 1440 10320 P (When) S 90 J ( a) S 91 J ( Decapsulator) S 90 J ( is) S 91 J ( using) S 90 J ( the) S 90 J ( received) S 90 J ( Flow) S 90 J ( ID) S 90 J ( in) S 90 J ( an) S 90 J ( Encapsulation) S 90 J ( Header) S 90 J ( to) S 90 J ( forward) S 90 J ( a) S 1440 10560 P (datagram) S 72 J ( to) S 73 J ( the) S 72 J ( next) S 73 J ( Decapsulator) S 73 J ( in) S 73 J ( a) S 73 J ( Flow,) S 73 J ( it) S 73 J ( is) S 73 J ( possible) S 73 J ( that) S 73 J ( the) S 73 J ( Flow) S 73 J ( ID) S 73 J ( may) S 73 J ( not) S 73 J ( be) S 73 J ( known.) S 1440 10800 P (For) S 110 J ( this) S 111 J ( case) S 110 J ( the) S 111 J ( Decapsulator) S 111 J ( will) S 111 J ( notify) S 111 J ( the) S 111 J ( previous) S 111 J ( Encapsulator) S 111 J ( that) S 111 J ( the) S 111 J ( Flow) S 111 J ( was) S 111 J ( not) S 1440 11040 P (known) S 72 J ( so) S 73 J ( that) S 72 J ( the) S 73 J ( problem) S 72 J ( may) S 73 J ( be) S 72 J ( reported) S 73 J ( to) S 73 J ( the) S 73 J ( layer) S 73 J ( responsible) S 73 J ( for) S 73 J ( the) S 73 J ( programming) S 73 J ( of) S 73 J ( the) S 1440 11280 P (Flow) S 60 J ( tables.) S 60 J ( ) S 60 J ( This) S 60 J ( is) S 60 J ( accomplished) S 60 J ( through) S 60 J ( an) S 60 J ( encapsulation) S 60 J ( error) S 60 J ( message.) S 1440 11760 P (If) S 80 J ( an) S 80 J ( Encapsulator) S 80 J ( receives) S 80 J ( an) S 80 J ( ICMP) S 80 J ( messages) S 80 J ( regarding) S 80 J ( a) S 80 J ( given) S 80 J ( flow,) S 80 J ( this) S 80 J ( message) S 80 J ( should) S 80 J ( be) S 1440 12000 P (forwarded) S 86 J ( backwards) S 87 J ( along) S 86 J ( the) S 87 J ( flow) S 86 J ( to) S 87 J ( the) S 86 J ( source) S 87 J ( Encapsulator.) S 86 J ( ) S 87 J ( This) S 86 J ( is) S 87 J ( accomplished) S 87 J ( by) S 87 J ( the) S 1440 12240 P (second) S 95 J ( kind) S 96 J ( of) S 95 J ( error) S 95 J ( message.) S 95 J ( ) S 95 J ( The) S 95 J ( ICMP) S 95 J ( message) S 95 J ( will) S 95 J ( contain) S 95 J ( the) S 95 J ( Flow) S 95 J ( ID) S 95 J ( of) S 95 J ( the) S 95 J ( message) S 1440 12480 P (which) S 121 J ( caused) S 122 J ( the) S 121 J ( error.) S 122 J ( ) S 121 J ( This) S 122 J ( Flow) S 121 J ( ID) S 122 J ( must) S 121 J ( be) S 122 J ( translated) S 121 J ( to) S 122 J ( the) S 121 J ( Flow) S 122 J ( ID) S 121 J ( relative) S 122 J ( to) S 122 J ( the) S 1440 12720 P (Encapsulator) S 60 J ( to) S 60 J ( which) S 60 J ( the) S 60 J ( error) S 60 J ( message) S 60 J ( is) S 60 J ( sent.) S 1440 13200 P (If) S 60 J ( an) S 60 J ( error) S 60 J ( occurs) S 60 J ( while) S 60 J ( sending) S 60 J ( any) S 60 J ( error) S 60 J ( message,) S 60 J ( no) S 60 J ( further) S 60 J ( error) S 60 J ( message) S 60 J ( are) S 60 J ( generated.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10153 14640 P (Page) S 60 J ( ) S (9) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1440 2160 P 0 12 F 24 12 F B (8.) S 60 J ( References) S E 1440 2640 P 0 12 F 24 12 F ([1]) S 440 J ( J.) S 60 J ( Postel,) S 60 J ( ) S 0 12 F 24 12 F I (Internet) S 60 J ( Control) S 60 J ( Message) S 60 J ( Protocol) S E 0 12 F 24 12 F (,) S 60 J ( RFC) S 60 J ( 792,) S 60 J ( September) S 60 J ( 1981.) S 1440 3120 P ([2]) S 440 J ( J.) S 60 J ( Postel,) S 60 J ( ) S 0 12 F 24 12 F I (Internet) S 60 J ( Protocol) S E 0 12 F 24 12 F (,) S 60 J ( RFC) S 60 J ( 791,) S 60 J ( September) S 60 J ( 1981.) S 1440 3600 P ([3]) S 440 J ( J.) S 60 J ( Postel,) S 60 J ( ) S 0 12 F 24 12 F I (Transmission) S 60 J ( Control) S 60 J ( Protocol) S E 0 12 F 24 12 F (,) S 60 J ( RFC) S 60 J ( 793,) S 60 J ( September) S 60 J ( 1981.) S 1440 4080 P ([4]) S 440 J ( ORWG,) S 84 J ( ) S 0 12 F 24 12 F I (Inter-Domain) S 85 J ( Policy) S 84 J ( Routing) S 85 J ( Protocol) S 84 J ( Specification) S 85 J ( and) S 84 J ( Usage) S E 0 12 F 24 12 F (,) S 85 J ( Draft,) S 85 J ( August) S 2160 4320 P (1990) S 1440 5040 P 0 12 F 24 12 F B (A.) S 60 J ( Packet) S 60 J ( Formats) S E 1440 5520 P 0 12 F 24 12 F (This) S 60 J ( section) S 60 J ( describes) S 60 J ( the) S 60 J ( packet) S 60 J ( formats) S 60 J ( for) S 60 J ( the) S 60 J ( encapsulation) S 60 J ( protocol.) S 3600 6000 P (0) S 540 J ( 4) S 600 J ( 8) S 540 J ( 12) S 480 J ( 16) S 1200 J ( 24) S 1200 J ( 31) S 3528 6120 P 0 12 F 57 12 F (ZDDDDBDDDDBDDDDBDDDDBDDDDDDDDDDDDDDDDDDD?) S 3744 6360 P 0 12 F 24 12 F (Vers) S 323 J ( HL) S 380 J ( MT) S 380 J ( RC) S 1133 J ( Checksum) S 1368 6360 P 0 12 F 57 12 F () S 2160 J ( 3) S 576 J ( 3) S 576 J ( 3) S 576 J ( 3) S 576 J ( 3) S 2736 J ( 3) S 3528 6600 P (CDDDDADDDDADDDDADDDDADDDDDDDDDDDDDDDDDDD4) S 3744 6840 P 0 12 F 24 12 F () S 2333 J ( Flow) S 60 J ( ID) S 1368 6840 P 0 12 F 57 12 F () S 2160 J ( 3) S 5616 J ( 3) S 3528 7080 P (@DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDY) S 3681 7680 P 0 12 F 24 12 F (Fig.) S 60 J ( A.1.) S 60 J ( ) S 60 J ( Encapsulation) S 60 J ( Protocol) S 60 J ( Header) S 60 J ( Example) S 1440 8160 P (Vers) S 987 J ( 4) S 60 J ( bits) S 913 J ( The) S 70 J ( version) S 71 J ( number) S 70 J ( of) S 71 J ( the) S 70 J ( encapsulation) S 71 J ( protocol.) S 71 J ( ) S 71 J ( The) S 71 J ( version) S 71 J ( of) S 4320 8400 P (the) S 60 J ( protocol) S 60 J ( described) S 60 J ( by) S 60 J ( this) S 60 J ( document) S 60 J ( is) S 60 J ( 1.) S 1440 8880 P (HL) S 1120 J ( 4) S 60 J ( bits) S 913 J ( The) S 60 J ( header) S 60 J ( length) S 60 J ( of) S 60 J ( the) S 60 J ( Encapsulation) S 60 J ( Protocol) S 60 J ( Header) S 60 J ( in) S 60 J ( octets.) S 1440 9360 P (MT) S 1080 J ( 4) S 60 J ( bits) S 913 J ( The) S 76 J ( message) S 76 J ( type) S 76 J ( of) S 76 J ( the) S 76 J ( Encapsulation) S 76 J ( Protocol) S 76 J ( message.) S 76 J ( ) S 76 J ( A) S 76 J ( data) S 4320 9600 P (message) S 62 J ( has) S 63 J ( a) S 62 J ( message) S 63 J ( type) S 62 J ( of) S 63 J ( 1.) S 63 J ( ) S 63 J ( An) S 63 J ( error) S 63 J ( message) S 63 J ( has) S 63 J ( a) S 63 J ( message) S 4320 9840 P (type) S 60 J ( of) S 60 J ( 2.) S 1440 10320 P (RC) S 1120 J ( 4) S 60 J ( bits) S 913 J ( The) S 94 J ( reason) S 95 J ( code.) S 94 J ( ) S 95 J ( This) S 94 J ( field) S 95 J ( is) S 94 J ( unused) S 95 J ( in) S 94 J ( the) S 95 J ( Data) S 95 J ( Message) S 95 J ( and) S 4320 10560 P (must) S 61 J ( have) S 61 J ( a) S 61 J ( value) S 61 J ( of) S 61 J ( 0.) S 61 J ( ) S 61 J ( In) S 61 J ( the) S 61 J ( Error) S 61 J ( Message) S 61 J ( it) S 61 J ( contains) S 61 J ( the) S 61 J ( reason) S 4320 10800 P (code) S 60 J ( for) S 60 J ( the) S 60 J ( Error) S 60 J ( Message.) S 60 J ( ) S 60 J ( Defined) S 60 J ( reason) S 60 J ( code) S 60 J ( values) S 60 J ( are:) S 5040 11040 P (1) S 240 J ( Unknown) S 60 J ( Flow) S 60 J ( ID) S 5040 11280 P (2) S 240 J ( ICMP) S 60 J ( returned) S 1440 11760 P (Checksum) S 426 J ( 16) S 60 J ( bits) S 793 J ( A) S 132 J ( one's) S 132 J ( complement) S 132 J ( checksum) S 132 J ( for) S 132 J ( the) S 132 J ( Encapsulation) S 132 J ( Protocol) S 4320 12000 P (Header.) S 60 J ( ) S 61 J ( This) S 60 J ( field) S 61 J ( is) S 60 J ( set) S 61 J ( to) S 60 J ( 0) S 61 J ( upon) S 60 J ( calculation) S 61 J ( of) S 60 J ( the) S 61 J ( checksum) S 60 J ( and) S 4320 12240 P (is) S 136 J ( filled) S 137 J ( with) S 136 J ( the) S 137 J ( checksum) S 137 J ( calculation) S 137 J ( result) S 137 J ( before) S 137 J ( the) S 137 J ( data) S 4320 12480 P (message) S 60 J ( is) S 60 J ( sent.) S 1440 12960 P (Flow) S 60 J ( ID) S 634 J ( 32) S 60 J ( bits) S 793 J ( The) S 63 J ( Flow) S 64 J ( ID) S 63 J ( as) S 64 J ( seen) S 64 J ( by) S 64 J ( the) S 64 J ( Decapsulator) S 64 J ( or) S 64 J ( Encapsulator) S 64 J ( to) S 64 J ( which) S 4320 13200 P (this) S 88 J ( message) S 89 J ( is) S 88 J ( being) S 89 J ( sent.) S 88 J ( ) S 89 J ( In) S 88 J ( the) S 89 J ( case) S 88 J ( of) S 89 J ( an) S 88 J ( Unknown) S 89 J ( Flow) S 89 J ( ID) S 4320 13440 P (error,) S 60 J ( the) S 60 J ( Flow) S 60 J ( ID) S 60 J ( causing) S 60 J ( the) S 60 J ( error) S 60 J ( is) S 60 J ( used.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10033 14640 P (Page) S 60 J ( ) S (10) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1440 2160 P (For) S 71 J ( Data) S 72 J ( Messages,) S 71 J ( the) S 72 J ( Encapsulation) S 72 J ( Protocol) S 72 J ( Header) S 72 J ( is) S 72 J ( followed) S 72 J ( by) S 72 J ( the) S 72 J ( Clear) S 72 J ( Datagram.) S 72 J ( ) S 72 J ( For) S 1440 2400 P (Error) S 60 J ( Messages,) S 60 J ( the) S 60 J ( header) S 60 J ( is) S 60 J ( followed) S 60 J ( by) S 60 J ( the) S 60 J ( ICMP) S 60 J ( message) S 60 J ( being) S 60 J ( forwarded) S 60 J ( along) S 60 J ( a) S 60 J ( flow.) S 1440 3120 P 0 12 F 24 12 F B (B.) S 60 J ( Encapsulation) S 60 J ( and) S 60 J ( Existing) S 60 J ( IP) S 60 J ( Mechanisms) S E 1440 3600 P 0 12 F 24 12 F (This) S 122 J ( section) S 123 J ( discusses) S 122 J ( in) S 123 J ( detail) S 122 J ( the) S 123 J ( effect) S 122 J ( of) S 123 J ( this) S 122 J ( encapsulation) S 122 J ( protocol) S 122 J ( upon) S 122 J ( the) S 122 J ( existing) S 1440 3840 P (mechanisms) S 127 J ( available) S 128 J ( with) S 127 J ( IP) S 128 J ( and) S 127 J ( some) S 128 J ( the) S 127 J ( possible) S 128 J ( effects) S 127 J ( of) S 128 J ( IP) S 128 J ( mechanisms) S 128 J ( upon) S 128 J ( this) S 1440 4080 P (protocol.) S 60 J ( ) S 60 J ( Specifically) S 60 J ( these) S 60 J ( are) S 60 J ( Fragmentation) S 60 J ( and) S 60 J ( ICMP) S 60 J ( messages.) S 1440 4560 P 0 12 F 24 12 F B (B.1) S 60 J ( Fragmentation) S 60 J ( and) S 60 J ( Maximum) S 60 J ( Transmission) S 60 J ( Unit) S E 1440 5040 P 0 12 F 24 12 F (An) S 85 J ( immediate) S 86 J ( concern) S 85 J ( of) S 86 J ( using) S 85 J ( an) S 86 J ( encapsulation) S 85 J ( mechanism) S 86 J ( is) S 85 J ( that) S 86 J ( of) S 85 J ( restrictions) S 85 J ( based) S 85 J ( upon) S 1440 5280 P (MTU) S 62 J ( size.) S 63 J ( ) S 62 J ( The) S 63 J ( source) S 62 J ( of) S 63 J ( a) S 62 J ( Clear) S 63 J ( Datagram) S 62 J ( is) S 63 J ( going) S 62 J ( to) S 63 J ( generate) S 63 J ( packets) S 63 J ( consistent) S 63 J ( with) S 63 J ( MTU) S 63 J ( of) S 1440 5520 P (the) S 66 J ( interface) S 67 J ( over) S 66 J ( which) S 67 J ( datagram) S 66 J ( is) S 67 J ( transmitted.) S 66 J ( ) S 67 J ( If) S 66 J ( these) S 66 J ( packets) S 66 J ( reach) S 66 J ( an) S 66 J ( Encapsulator) S 66 J ( and) S 66 J ( are) S 1440 5760 P (encapsulated,) S 65 J ( they) S 66 J ( may) S 65 J ( be) S 66 J ( fragmented) S 66 J ( if) S 66 J ( they) S 66 J ( are) S 66 J ( larger) S 66 J ( than) S 66 J ( the) S 66 J ( MTU) S 66 J ( of) S 66 J ( the) S 66 J ( Encapsulator,) S 66 J ( even) S 1440 6000 P (though) S 130 J ( the) S 131 J ( physical) S 130 J ( interfaces) S 130 J ( of) S 130 J ( the) S 130 J ( source) S 130 J ( and) S 130 J ( Encapsulator) S 130 J ( may) S 130 J ( have) S 130 J ( the) S 130 J ( same) S 130 J ( MTU.) S 1440 6240 P (Because) S 71 J ( the) S 72 J ( Encapsulated) S 71 J ( Datagram) S 72 J ( is) S 71 J ( sent) S 72 J ( to) S 72 J ( the) S 72 J ( Decapsulator) S 72 J ( using) S 72 J ( IP,) S 72 J ( there) S 72 J ( is) S 72 J ( no) S 72 J ( problem) S 72 J ( in) S 1440 6480 P (allowing) S 76 J ( IP) S 77 J ( to) S 76 J ( perform) S 77 J ( fragmentation) S 76 J ( and) S 77 J ( reassembly.) S 76 J ( ) S 77 J ( However,) S 76 J ( fragmentation) S 76 J ( is) S 76 J ( known) S 76 J ( to) S 76 J ( be) S 1440 6720 P (inefficient) S 100 J ( and) S 101 J ( is) S 100 J ( generally) S 101 J ( avoided.) S 100 J ( ) S 100 J ( Because) S 100 J ( a) S 100 J ( new) S 100 J ( header) S 100 J ( is) S 100 J ( being) S 100 J ( prepended) S 100 J ( to) S 100 J ( the) S 100 J ( Clear) S 1440 6960 P (Datagram) S 82 J ( by) S 83 J ( the) S 82 J ( encapsulation) S 83 J ( process,) S 82 J ( the) S 83 J ( likelihood) S 82 J ( of) S 83 J ( fragmentation) S 83 J ( occurring) S 83 J ( is) S 83 J ( increased.) S 1440 7200 P (If) S 78 J ( the) S 79 J ( Encapsulator) S 78 J ( decides) S 79 J ( to) S 78 J ( disallow) S 79 J ( fragmentation) S 78 J ( through) S 79 J ( the) S 78 J ( Encapsulation) S 79 J ( Space,) S 78 J ( it) S 79 J ( must) S 1440 7440 P (send) S 90 J ( an) S 91 J ( ICMP) S 90 J ( message) S 91 J ( back) S 90 J ( to) S 91 J ( the) S 90 J ( source.) S 91 J ( ) S 90 J ( This) S 91 J ( means) S 90 J ( that) S 90 J ( the) S 90 J ( MTU) S 90 J ( of) S 90 J ( the) S 90 J ( interface) S 90 J ( in) S 90 J ( the) S 1440 7680 P (encapsulation) S 60 J ( space) S 60 J ( is) S 60 J ( effectively) S 60 J ( smaller) S 60 J ( than) S 60 J ( that) S 60 J ( of) S 60 J ( the) S 60 J ( physical) S 60 J ( MTU) S 60 J ( of) S 60 J ( the) S 60 J ( interface.) S 1440 8160 P (Fragmentation) S 244 J ( by) S 245 J ( intermediate) S 244 J ( User) S 245 J ( Space) S 245 J ( Gateways) S 245 J ( introduces) S 245 J ( another) S 245 J ( problem.) S 1440 8400 P (Fragmentation) S 74 J ( occurs) S 75 J ( at) S 74 J ( the) S 75 J ( IP) S 74 J ( level.) S 75 J ( ) S 74 J ( If) S 75 J ( a) S 74 J ( TCP) S 75 J ( protocol) S 75 J ( is) S 75 J ( in) S 75 J ( use) S 75 J ( and) S 75 J ( fragmentation) S 75 J ( occurs,) S 75 J ( the) S 1440 8640 P (TCP) S 99 J ( header) S 100 J ( is) S 99 J ( contained) S 100 J ( in) S 99 J ( the) S 100 J ( first) S 99 J ( fragment,) S 100 J ( but) S 99 J ( not) S 100 J ( the) S 99 J ( following) S 100 J ( fragments.) S 99 J ( [3]) S 100 J ( ) S 99 J ( If) S 99 J ( these) S 1440 8880 P (fragments) S 62 J ( are) S 63 J ( forwarded) S 62 J ( by) S 63 J ( an) S 62 J ( Encapsulator,) S 63 J ( discrimination) S 62 J ( of) S 63 J ( the) S 62 J ( Clear) S 63 J ( Header) S 63 J ( for) S 63 J ( a) S 63 J ( given) S 63 J ( flow) S 1440 9120 P (will) S 91 J ( only) S 92 J ( be) S 91 J ( able) S 92 J ( to) S 91 J ( occur) S 92 J ( on) S 91 J ( the) S 92 J ( IP) S 91 J ( header) S 92 J ( portion) S 91 J ( of) S 92 J ( the) S 92 J ( Clear) S 92 J ( Header.) S 92 J ( ) S 92 J ( If) S 92 J ( discrimination) S 92 J ( is) S 1440 9360 P (attempted) S 71 J ( on) S 72 J ( the) S 71 J ( TCP) S 72 J ( portion) S 71 J ( of) S 72 J ( the) S 71 J ( header,) S 72 J ( then) S 72 J ( only) S 72 J ( the) S 72 J ( first) S 72 J ( fragment) S 72 J ( will) S 72 J ( be) S 72 J ( matched,) S 72 J ( while) S 1440 9600 P (remaining) S 60 J ( fragments) S 60 J ( will) S 60 J ( not.) S 1440 10080 P 0 12 F 24 12 F B (B.2) S 60 J ( ICMP) S 60 J ( Messages) S E 1440 10560 P 0 12 F 24 12 F (The) S 72 J ( most) S 73 J ( controversial) S 72 J ( aspect) S 73 J ( of) S 72 J ( encapsulation) S 73 J ( is) S 72 J ( the) S 73 J ( handling) S 72 J ( of) S 72 J ( ICMP) S 72 J ( messages.) S 72 J ( [1]) S 72 J ( ) S 72 J ( Because) S 1440 10800 P (the) S 81 J ( Encapsulation) S 82 J ( Header) S 81 J ( contains) S 82 J ( the) S 81 J ( source) S 82 J ( address) S 81 J ( of) S 82 J ( the) S 81 J ( Encapsulator) S 81 J ( in) S 81 J ( the) S 81 J ( Encapsulation) S 1440 11040 P (Space,) S 96 J ( ICMP) S 97 J ( messages) S 96 J ( which) S 96 J ( occur) S 96 J ( within) S 96 J ( the) S 96 J ( Encapsulation) S 96 J ( Space) S 96 J ( will) S 96 J ( be) S 96 J ( sent) S 96 J ( back) S 96 J ( to) S 96 J ( the) S 1440 11280 P (Encapsulator.) S 82 J ( ) S 83 J ( Once) S 82 J ( the) S 83 J ( Encapsulator) S 82 J ( receives) S 83 J ( the) S 82 J ( ICMP) S 83 J ( message,) S 82 J ( the) S 83 J ( question) S 82 J ( is) S 83 J ( what) S 82 J ( should) S 1440 11520 P (the) S 88 J ( next) S 89 J ( action) S 89 J ( be.) S 89 J ( ) S 89 J ( Since) S 89 J ( the) S 89 J ( original) S 89 J ( source) S 89 J ( of) S 89 J ( the) S 89 J ( Clear) S 89 J ( Datagram) S 89 J ( knows) S 89 J ( nothing) S 89 J ( about) S 89 J ( the) S 1440 11760 P (Encapsulation) S 85 J ( Space,) S 86 J ( it) S 85 J ( does) S 86 J ( not) S 86 J ( make) S 86 J ( sense) S 86 J ( to) S 86 J ( forward) S 86 J ( an) S 86 J ( ICMP) S 86 J ( message) S 86 J ( on) S 86 J ( to) S 86 J ( it) S 86 J ( and) S 86 J ( ICMP) S 1440 12000 P (message) S 122 J ( are) S 123 J ( not) S 123 J ( supposed) S 123 J ( to) S 123 J ( beget) S 123 J ( ICMP) S 123 J ( messages.) S 123 J ( ) S 123 J ( Yet) S 123 J ( not) S 123 J ( sending) S 123 J ( the) S 123 J ( original) S 123 J ( source) S 1440 12240 P (something) S 60 J ( may) S 60 J ( break) S 60 J ( some) S 60 J ( important) S 60 J ( mechanisms.) S 1440 12720 P (In) S 63 J ( addition) S 64 J ( to) S 63 J ( deciding) S 64 J ( what) S 63 J ( to) S 64 J ( forward) S 63 J ( to) S 64 J ( the) S 63 J ( source) S 64 J ( of) S 63 J ( the) S 63 J ( Clear) S 63 J ( Datagram,) S 63 J ( there) S 63 J ( is) S 63 J ( the) S 63 J ( problem) S 1440 12960 P (of) S 69 J ( possibly) S 69 J ( not) S 69 J ( having) S 69 J ( enough) S 69 J ( information) S 69 J ( to) S 69 J ( send) S 69 J ( anything) S 69 J ( at) S 69 J ( all) S 69 J ( back) S 69 J ( to) S 69 J ( the) S 69 J ( source.) S 69 J ( ) S 69 J ( An) S 69 J ( ICMP) S 1440 13200 P (message) S 81 J ( returns) S 81 J ( the) S 81 J ( header) S 81 J ( of) S 81 J ( the) S 81 J ( offending) S 81 J ( message) S 81 J ( and) S 81 J ( the) S 81 J ( first) S 81 J ( eight) S 81 J ( octets) S 81 J ( of) S 81 J ( the) S 81 J ( data) S 81 J ( after) S 1440 13440 P (the) S 88 J ( header.) S 89 J ( ) S 88 J ( For) S 89 J ( the) S 88 J ( case) S 89 J ( of) S 89 J ( the) S 89 J ( encapsulation) S 89 J ( protocol,) S 89 J ( this) S 89 J ( translates) S 89 J ( to) S 89 J ( the) S 89 J ( IP) S 89 J ( portion) S 89 J ( of) S 89 J ( the) S 1440 13680 P (Encapsulation) S 84 J ( Header,) S 85 J ( the) S 84 J ( first) S 85 J ( eight) S 84 J ( octets) S 85 J ( of) S 84 J ( the) S 85 J ( Encapsulation) S 85 J ( Protocol) S 85 J ( Header,) S 85 J ( and) S 85 J ( nothing) S 1440 13920 P (else.) S 62 J ( ) S 63 J ( The) S 62 J ( contents) S 63 J ( of) S 62 J ( the) S 62 J ( Clear) S 62 J ( Datagram) S 62 J ( are) S 62 J ( completely) S 62 J ( lost.) S 62 J ( ) S 62 J ( Therefore,) S 62 J ( for) S 62 J ( the) S 62 J ( Encapsulator) S 62 J ( to) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10033 14640 P (Page) S 60 J ( ) S (11) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1440 2160 P (send) S 67 J ( an) S 68 J ( ICMP) S 67 J ( message) S 68 J ( back) S 67 J ( to) S 68 J ( the) S 67 J ( source) S 68 J ( it) S 67 J ( has) S 68 J ( to) S 68 J ( reconstruct) S 68 J ( the) S 68 J ( Clear) S 68 J ( Header.) S 68 J ( ) S 68 J ( However,) S 68 J ( it) S 68 J ( is) S 1440 2400 P (essentially) S 60 J ( impossible) S 60 J ( to) S 60 J ( reproduce) S 60 J ( the) S 60 J ( exact) S 60 J ( header.) S 1440 2880 P (For) S 92 J ( the) S 93 J ( purpose) S 92 J ( of) S 93 J ( this) S 92 J ( specification,) S 93 J ( the) S 92 J ( Flow) S 93 J ( ID) S 92 J ( has) S 93 J ( been) S 92 J ( assumed) S 93 J ( to) S 92 J ( be) S 93 J ( a) S 93 J ( unique) S 93 J ( one) S 93 J ( way) S 1440 3120 P (mapping) S 87 J ( from) S 88 J ( a) S 87 J ( Clear) S 88 J ( Header.) S 87 J ( ) S 88 J ( There) S 87 J ( is) S 88 J ( no) S 87 J ( guarantee) S 88 J ( that) S 87 J ( the) S 87 J ( Flow) S 87 J ( ID) S 87 J ( could) S 87 J ( be) S 87 J ( used) S 87 J ( to) S 87 J ( map) S 1440 3360 P (back) S 80 J ( to) S 81 J ( the) S 80 J ( Clear) S 80 J ( Header,) S 80 J ( ) S 80 J ( since) S 80 J ( several) S 80 J ( headers) S 80 J ( potentially) S 80 J ( map) S 80 J ( to) S 80 J ( the) S 80 J ( same) S 80 J ( flow.) S 80 J ( ) S 80 J ( With) S 80 J ( there) S 1440 3600 P (being) S 139 J ( no) S 140 J ( effective) S 139 J ( way) S 140 J ( to) S 139 J ( regenerate) S 140 J ( the) S 139 J ( original) S 140 J ( datagram,) S 140 J ( some) S 140 J ( compromises) S 140 J ( must) S 140 J ( be) S 1440 3840 P (examined.) S 1440 4320 P (For) S 63 J ( each) S 64 J ( of) S 63 J ( the) S 64 J ( possible) S 63 J ( ICMP) S 64 J ( messages,) S 63 J ( the) S 64 J ( alternatives) S 63 J ( and) S 64 J ( impact) S 63 J ( will) S 64 J ( be) S 64 J ( assessed.) S 64 J ( ) S 64 J ( There) S 64 J ( are) S 1440 4560 P (three) S 86 J ( categories) S 87 J ( of) S 86 J ( ICMP) S 87 J ( message) S 86 J ( involved.) S 87 J ( ) S 86 J ( The) S 87 J ( first) S 86 J ( is) S 86 J ( those) S 86 J ( ICMP) S 86 J ( messages) S 86 J ( which) S 86 J ( are) S 86 J ( not) S 1440 4800 P (applicable) S 220 J ( in) S 221 J ( the) S 220 J ( context) S 221 J ( of) S 220 J ( Encapsulation.) S 221 J ( ) S 221 J ( These) S 221 J ( are:) S 221 J ( ) S 221 J ( Echo/Echo) S 221 J ( Reply) S 221 J ( and) S 1440 5040 P (Timestamp/Timestamp) S 60 J ( Reply.) S 1440 5520 P (The) S 142 J ( second) S 143 J ( category) S 142 J ( are) S 143 J ( those) S 142 J ( ICMP) S 143 J ( messages) S 142 J ( which) S 143 J ( concern) S 143 J ( mechanisms) S 143 J ( local) S 143 J ( to) S 143 J ( the) S 1440 5760 P (encapsulation) S 62 J ( domain.) S 63 J ( ) S 63 J ( These) S 63 J ( are) S 63 J ( messages) S 63 J ( which) S 63 J ( would) S 63 J ( not) S 63 J ( make) S 63 J ( sense) S 63 J ( to) S 63 J ( the) S 63 J ( original) S 63 J ( source) S 63 J ( if) S 1440 6000 P (it) S 65 J ( did) S 66 J ( receive) S 65 J ( them.) S 66 J ( ) S 65 J ( In) S 66 J ( these) S 65 J ( cases) S 66 J ( the) S 65 J ( encapsulator) S 66 J ( will) S 65 J ( have) S 66 J ( to) S 65 J ( decide) S 66 J ( what) S 65 J ( to) S 66 J ( do,) S 65 J ( but) S 65 J ( no) S 65 J ( ICMP) S 1440 6240 P (message) S 83 J ( need) S 84 J ( be) S 83 J ( sent) S 84 J ( back) S 83 J ( to) S 84 J ( the) S 83 J ( original) S 83 J ( source.) S 83 J ( ) S 83 J ( The) S 83 J ( datagram) S 83 J ( will) S 83 J ( simply) S 83 J ( be) S 83 J ( lost,) S 83 J ( IP) S 83 J ( is) S 83 J ( not) S 1440 6480 P (meant) S 71 J ( to) S 72 J ( be) S 71 J ( a) S 71 J ( reliable) S 71 J ( protocol.) S 71 J ( ) S 71 J ( Subsequent) S 71 J ( messages) S 71 J ( received) S 71 J ( for) S 71 J ( encapsulation) S 71 J ( may) S 71 J ( cause) S 71 J ( the) S 1440 6720 P (encapsulator) S 72 J ( to) S 73 J ( generate) S 72 J ( ICMP) S 73 J ( Destination) S 72 J ( Unreachable) S 73 J ( messages) S 72 J ( back) S 73 J ( to) S 72 J ( the) S 73 J ( original) S 72 J ( source) S 73 J ( if) S 1440 6960 P (the) S 67 J ( encapsulator) S 68 J ( can) S 67 J ( no) S 68 J ( longer) S 67 J ( send) S 68 J ( messages) S 67 J ( to) S 68 J ( the) S 67 J ( destination) S 68 J ( decapsulator.) S 67 J ( ) S 67 J ( This) S 67 J ( requires) S 67 J ( that) S 1440 7200 P (ICMP) S 80 J ( messages) S 80 J ( inside) S 80 J ( the) S 80 J ( encapsulation) S 80 J ( domain) S 80 J ( affect) S 80 J ( the) S 80 J ( mapping) S 80 J ( from) S 80 J ( the) S 80 J ( Flow) S 80 J ( ID.) S 80 J ( ) S 80 J ( ICMP) S 1440 7440 P (messages) S 91 J ( in) S 92 J ( the) S 91 J ( second) S 92 J ( category) S 91 J ( are:) S 92 J ( ) S 92 J ( Parameter) S 92 J ( Problem,) S 92 J ( Redirect,) S 92 J ( Destination) S 92 J ( Unreachable,) S 1440 7680 P (Time) S 60 J ( Exceeded.) S 1440 8160 P (Finally) S 95 J ( there) S 96 J ( is) S 95 J ( one) S 96 J ( ICMP) S 95 J ( message) S 96 J ( which) S 95 J ( has) S 96 J ( direct) S 95 J ( bearing) S 96 J ( on) S 95 J ( the) S 96 J ( operation) S 95 J ( of) S 95 J ( the) S 95 J ( original) S 1440 8400 P (source) S 85 J ( of) S 86 J ( datagrams) S 85 J ( destined) S 86 J ( for) S 85 J ( encapsulation,) S 86 J ( the) S 85 J ( ICMP) S 86 J ( Source) S 85 J ( Quench) S 86 J ( message.) S 86 J ( ) S 86 J ( The) S 86 J ( only) S 1440 8640 P (possible) S 117 J ( mechanism) S 118 J ( available) S 117 J ( to) S 118 J ( the) S 117 J ( Encapsulator) S 117 J ( to) S 117 J ( handle) S 117 J ( this) S 117 J ( message) S 117 J ( is) S 117 J ( for) S 117 J ( the) S 117 J ( source) S 1440 8880 P (quench) S 62 J ( message) S 63 J ( set) S 62 J ( a) S 63 J ( flag) S 63 J ( for) S 63 J ( the) S 63 J ( offending) S 63 J ( Flow) S 63 J ( ID) S 63 J ( such) S 63 J ( that) S 63 J ( subsequent) S 63 J ( messages) S 63 J ( that) S 63 J ( map) S 63 J ( the) S 1440 9120 P (Flow) S 70 J ( cause) S 71 J ( the) S 70 J ( generation) S 71 J ( of) S 70 J ( a) S 71 J ( source) S 70 J ( quench) S 70 J ( back) S 70 J ( to) S 70 J ( the) S 70 J ( original) S 70 J ( source) S 70 J ( before) S 70 J ( the) S 70 J ( datagram) S 70 J ( is) S 1440 9360 P (encapsulated.) S 1440 9840 P (This) S 73 J ( last) S 74 J ( mechanism) S 73 J ( may) S 74 J ( be) S 73 J ( a) S 74 J ( solution) S 73 J ( for) S 74 J ( the) S 73 J ( more) S 74 J ( general) S 73 J ( problem.) S 74 J ( ) S 73 J ( The) S 74 J ( rule) S 73 J ( of) S 74 J ( thumb) S 73 J ( could) S 1440 10080 P (be) S 65 J ( that) S 66 J ( when) S 65 J ( an) S 66 J ( ICMP) S 66 J ( message) S 66 J ( is) S 66 J ( received) S 66 J ( for) S 66 J ( a) S 66 J ( given) S 66 J ( flow,) S 66 J ( then) S 66 J ( flag) S 66 J ( the) S 66 J ( Flow) S 66 J ( so) S 66 J ( that) S 66 J ( then) S 66 J ( next) S 1440 10320 P (message) S 78 J ( encapsulated) S 79 J ( will) S 78 J ( cause) S 79 J ( the) S 78 J ( next) S 79 J ( message) S 78 J ( encapsulated) S 79 J ( on) S 78 J ( that) S 79 J ( flow) S 78 J ( to) S 78 J ( force) S 78 J ( an) S 78 J ( ICMP) S 1440 10560 P (message) S 77 J ( to) S 78 J ( the) S 77 J ( source.) S 78 J ( ) S 77 J ( After) S 78 J ( the) S 77 J ( ICMP) S 77 J ( message) S 77 J ( is) S 77 J ( sent) S 77 J ( to) S 77 J ( the) S 77 J ( source,) S 77 J ( the) S 77 J ( mechanism) S 77 J ( could) S 77 J ( be) S 1440 10800 P (reset.) S 62 J ( ) S 63 J ( This) S 62 J ( would) S 63 J ( effectively) S 62 J ( cause) S 63 J ( every) S 62 J ( other) S 63 J ( packet) S 62 J ( to) S 62 J ( receive) S 62 J ( an) S 62 J ( ICMP) S 62 J ( message) S 62 J ( if) S 62 J ( there) S 62 J ( were) S 1440 11040 P (a) S 105 J ( persistent) S 106 J ( problem.) S 105 J ( ) S 106 J ( This) S 105 J ( mechanism) S 106 J ( is) S 105 J ( probably) S 106 J ( only) S 105 J ( safe) S 106 J ( for) S 105 J ( Unreachable) S 106 J ( messages) S 106 J ( and) S 1440 11280 P (Source) S 60 J ( Quench.) S 1440 12000 P 0 12 F 24 12 F B (C.) S 60 J ( Reception) S 60 J ( of) S 60 J ( Clear) S 60 J ( Datagrams) S E 1440 12480 P 0 12 F 24 12 F (In) S 89 J ( order) S 90 J ( to) S 89 J ( use) S 90 J ( the) S 89 J ( encapsulation) S 90 J ( protocol) S 89 J ( a) S 90 J ( modification) S 89 J ( is) S 90 J ( required) S 89 J ( to) S 90 J ( IP) S 90 J ( forwarding.) S 90 J ( ) S 90 J ( There) S 1440 12720 P (must) S 77 J ( be) S 78 J ( some) S 78 J ( way) S 78 J ( for) S 78 J ( the) S 78 J ( IP) S 78 J ( module) S 78 J ( in) S 78 J ( a) S 78 J ( system) S 78 J ( to) S 78 J ( pass) S 78 J ( Clear) S 78 J ( Datagrams) S 78 J ( to) S 78 J ( the) S 78 J ( encapsulation) S 1440 12960 P (protocol.) S 89 J ( ) S 90 J ( A) S 90 J ( suggested) S 90 J ( means) S 90 J ( of) S 90 J ( doing) S 90 J ( this) S 90 J ( is) S 90 J ( to) S 90 J ( make) S 90 J ( an) S 90 J ( addition) S 90 J ( to) S 90 J ( a) S 90 J ( system's) S 90 J ( routing) S 90 J ( table) S 1440 13200 P (structures.) S 141 J ( ) S 142 J ( A) S 141 J ( flag) S 142 J ( could) S 141 J ( be) S 142 J ( added) S 141 J ( to) S 142 J ( a) S 141 J ( route) S 142 J ( that) S 141 J ( tells) S 142 J ( the) S 141 J ( forwarding) S 142 J ( function) S 142 J ( to) S 142 J ( use) S 1440 13440 P (encapsulation.) S 60 J ( ) S 60 J ( Note) S 60 J ( that) S 60 J ( the) S 60 J ( default) S 60 J ( route) S 60 J ( could) S 60 J ( also) S 60 J ( be) S 60 J ( set) S 60 J ( to) S 60 J ( use) S 60 J ( encapsulation.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10033 14640 P (Page) S 60 J ( ) S (12) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1440 2160 P (With) S 81 J ( this) S 82 J ( mechanism) S 81 J ( in) S 82 J ( place,) S 81 J ( a) S 82 J ( system's) S 81 J ( IP) S 82 J ( forwarding) S 81 J ( mechanism) S 82 J ( would) S 82 J ( examine) S 82 J ( its) S 82 J ( routing) S 1440 2400 P (tables) S 76 J ( to) S 77 J ( try) S 76 J ( and) S 77 J ( match) S 76 J ( the) S 77 J ( IP) S 77 J ( destination) S 77 J ( to) S 77 J ( a) S 77 J ( specific) S 77 J ( route.) S 77 J ( ) S 77 J ( If) S 77 J ( a) S 77 J ( route) S 77 J ( was) S 77 J ( found,) S 77 J ( it) S 77 J ( would) S 77 J ( be) S 1440 2640 P (then) S 115 J ( checked) S 116 J ( to) S 115 J ( see) S 116 J ( if) S 115 J ( encapsulation) S 116 J ( should) S 115 J ( be) S 116 J ( used.) S 115 J ( ) S 116 J ( If) S 116 J ( not) S 116 J ( the) S 116 J ( packet) S 116 J ( would) S 116 J ( be) S 116 J ( handled) S 1440 2880 P (normally.) S 99 J ( ) S 100 J ( If) S 99 J ( encapsulation) S 100 J ( was) S 99 J ( turned) S 100 J ( on) S 99 J ( for) S 100 J ( the) S 99 J ( route,) S 100 J ( then) S 99 J ( the) S 100 J ( datagram) S 99 J ( would) S 100 J ( be) S 99 J ( sent) S 99 J ( to) S 1440 3120 P (encapsulation) S 60 J ( for) S 60 J ( forwarding.) S 1440 3600 P (In) S 111 J ( addition) S 112 J ( to) S 111 J ( snagging) S 112 J ( packets) S 112 J ( as) S 112 J ( they) S 112 J ( are) S 112 J ( forwarded,) S 112 J ( something) S 112 J ( must) S 112 J ( be) S 112 J ( done) S 112 J ( at) S 112 J ( the) S 112 J ( last) S 1440 3840 P (Decapsulator) S 68 J ( on) S 69 J ( a) S 68 J ( given) S 69 J ( flow) S 68 J ( so) S 69 J ( that) S 68 J ( packets) S 69 J ( that) S 68 J ( are) S 69 J ( decapsulated) S 68 J ( are) S 69 J ( properly) S 69 J ( dumped) S 69 J ( into) S 69 J ( the) S 1440 4080 P (IP) S 77 J ( module) S 78 J ( for) S 77 J ( delivery.) S 78 J ( ) S 77 J ( Because) S 78 J ( the) S 77 J ( packets) S 78 J ( are) S 77 J ( encapsulated) S 78 J ( just) S 77 J ( before) S 78 J ( forwarding,) S 77 J ( it) S 77 J ( should) S 1440 4320 P (be) S 109 J ( a) S 109 J ( simple) S 109 J ( matter) S 109 J ( for) S 109 J ( decapsulated) S 109 J ( datagrams) S 109 J ( to) S 109 J ( be) S 109 J ( injected) S 109 J ( into) S 109 J ( the) S 109 J ( output) S 109 J ( portion) S 109 J ( of) S 109 J ( IP.) S 1440 4560 P (However,) S 65 J ( the) S 66 J ( source) S 65 J ( address) S 66 J ( in) S 65 J ( the) S 66 J ( Clear) S 65 J ( Header) S 66 J ( must) S 65 J ( not) S 66 J ( change.) S 65 J ( ) S 65 J ( The) S 65 J ( address) S 65 J ( must) S 65 J ( remain) S 65 J ( the) S 1440 4800 P (address) S 132 J ( of) S 133 J ( the) S 132 J ( source) S 132 J ( in) S 132 J ( the) S 132 J ( source) S 132 J ( User) S 132 J ( Space) S 132 J ( and) S 132 J ( not) S 132 J ( be) S 132 J ( overwritten) S 132 J ( with) S 132 J ( that) S 132 J ( of) S 132 J ( the) S 1440 5040 P (Decapsulator.) S 1440 5760 P 0 12 F 24 12 F B (D.) S 60 J ( Construction) S 60 J ( of) S 60 J ( Virtual) S 60 J ( Networks) S 60 J ( with) S 60 J ( Encapsulation) S E 1440 6240 P 0 12 F 24 12 F (Because) S 74 J ( of) S 75 J ( the) S 74 J ( modification) S 75 J ( to) S 74 J ( the) S 75 J ( routing) S 75 J ( table) S 75 J ( to) S 75 J ( permit) S 75 J ( encapsulation,) S 75 J ( it) S 75 J ( becomes) S 75 J ( possible) S 75 J ( to) S 1440 6480 P (specify) S 69 J ( a) S 70 J ( virtual) S 69 J ( interface) S 70 J ( whose) S 70 J ( sole) S 70 J ( purpose) S 70 J ( is) S 70 J ( encapsulation.) S 70 J ( ) S 70 J ( Using) S 70 J ( this) S 70 J ( mechanism,) S 70 J ( it) S 70 J ( would) S 1440 6720 P (become) S 133 J ( possible) S 134 J ( to) S 133 J ( link) S 134 J ( topologically) S 133 J ( distant) S 133 J ( entities) S 133 J ( with) S 133 J ( Flows.) S 133 J ( ) S 133 J ( This) S 133 J ( would) S 133 J ( allow) S 133 J ( the) S 1440 6960 P (construction) S 60 J ( of) S 61 J ( a) S 60 J ( Virtual) S 61 J ( Network) S 60 J ( which) S 61 J ( would) S 61 J ( overlay) S 61 J ( the) S 61 J ( actual) S 61 J ( routing) S 61 J ( topology.) S 61 J ( ) S 61 J ( An) S 61 J ( example) S 1440 7200 P (of) S 60 J ( such) S 60 J ( a) S 60 J ( virtual) S 60 J ( network) S 60 J ( is) S 60 J ( shown) S 60 J ( in) S 60 J ( Fig.) S 60 J ( 4.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10033 14640 P (Page) S 60 J ( ) S (13) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1080 1920 P II1 1080 9201 IX 10080 12960 7281 9360 IS 0 15840 IX II2 %%BeginDocument: RFC-FIG4.EPS %!PS-Adobe-2.0 EPSF-1.2 %%Title: RFC-FIG4.EPS %%Creator: Freelance Plus 3.01 %%CreationDate: 1/16/1991 %%Pages: 1 %%DocumentFonts: (atend) %%BoundingBox: 0 0 648 468 %%EndComments %%BeginProcSet: Freelance Plus /Freelance_Plus dup 100 dict def load begin [ ] {bind} stopped { (patching the bind operator...) = flush /*bind /bind load def /bind { dup xcheck { *bind } if } *bind def } if pop /bdf {bind def} bind def /ldf {load def} bdf /mt /moveto ldf /rt /rmoveto ldf /l2 /lineto ldf /c2 /curveto ldf /sg /setgray ldf /gs /gsave ldf /ef /eofill ldf /rl2 /rlineto ldf /st /stroke ldf /gr /grestore ldf /np /newpath ldf /sv /save ldf /su /statusdict ldf /rs /restore ldf /sw /setlinewidth ldf /sd /setdash ldf /cp /closepath ldf /ed {exch def } bdf /cfnt {findfont exch makefont setfont} bdf /itr {transform round exch round exch itransform} bdf /fres 72 0 matrix currentmatrix dtransform exch dup mul exch dup mul add sqrt def /res fres def /mcm matrix currentmatrix bdf %%EndProcSet end %%EndProlog %%BeginSetup Freelance_Plus begin save newpath .1 .1 scale /ecm matrix currentmatrix bdf /sem {ecm setmatrix} bdf -720 -720 translate 2 setlinecap 0 setlinejoin 1.42 setmiterlimit%%EndSetup 0.000 sg 6 sw sv np [] 0 sd 1821 3765 itr mt currentpoint translate np 0.987 1.000 scale 0 0 922 0.000 360.000 arc sem st rs sv np 2310 1993 itr mt currentpoint translate np 0.987 1.000 scale 0 0 922 0.000 360.000 arc sem st rs sv np 3573 3319 itr mt currentpoint translate np 0.987 1.000 scale 0 0 922 0.000 360.000 arc sem st rs sv np 4375 1675 itr mt currentpoint translate np 0.987 1.000 scale 0 0 922 0.000 360.000 arc sem st rs sv np 5276 3931 itr mt currentpoint translate np 0.987 1.000 scale 0 0 922 0.000 360.000 arc sem st rs sv np 6098 2287 itr mt currentpoint translate np 0.987 1.000 scale 0 0 922 0.000 360.000 arc sem st rs sv np 2083 2903 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 1614 3540 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 2279 3528 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 1946 4152 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 1154 4140 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 1712 2253 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 2524 2253 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 2201 1705 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 2857 1692 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 2093 1233 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 2690 3502 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 2925 2674 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 3972 2508 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 4423 3604 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 5705 3120 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 5254 1960 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 3493 3872 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 3493 3311 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 3493 2776 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 3698 1526 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 4383 1195 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 4383 1845 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 4873 1386 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 4853 2215 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 4853 4458 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 4853 3897 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 5695 3897 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 5695 4395 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 5049 3375 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 5695 2559 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 5714 1781 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 6018 2266 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 6754 2683 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs sv np 6716 1788 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs 12 sw sv np 1145 4148 itr mt 1616 3535 itr l2 st rs sv np 1616 3535 itr mt 1947 4148 itr l2 st rs sv np 2075 2922 itr mt 1616 3535 itr l2 st rs sv np 1947 4148 itr mt 2290 3518 itr l2 st rs sv np 2290 3518 itr mt 2087 2905 itr l2 st rs sv np 1718 2242 itr mt 2099 2922 itr l2 st rs sv np 2099 2922 itr mt 2519 2259 itr l2 st rs sv np 2532 2259 itr mt 2215 1729 itr l2 st rs sv np 2201 1695 itr mt 2099 1215 itr l2 st rs sv np 2189 1712 itr mt 2863 1695 itr l2 st rs sv np 2519 2259 itr mt 2865 1687 itr l2 st rs sv np 2927 2690 itr mt 2856 1687 itr l2 st rs sv np 2927 2681 itr mt 1716 2248 itr l2 st rs sv np 2694 3499 itr mt 2281 3534 itr l2 st rs sv np 2703 3499 itr mt 3502 3874 itr l2 st rs sv np 3502 3874 itr mt 3502 3312 itr l2 st rs sv np 2694 3511 itr mt 3502 3312 itr l2 st rs sv np 3502 3312 itr mt 2927 2681 itr l2 st rs sv np 3502 2775 itr mt 3502 3324 itr l2 st rs sv np [40] 20 sd 3502 3312 itr mt 3977 2506 itr l2 st rs sv np [40] 20 sd 3493 3312 itr mt 4426 3616 itr l2 st rs sv np [40] 20 sd 3493 2763 itr mt 3977 2494 itr l2 st rs sv np [40] 20 sd 3977 2517 itr mt 3699 1512 itr l2 st rs sv np [40] 20 sd 3699 1524 itr mt 4381 1851 itr l2 st rs sv np [40] 20 sd 3969 2494 itr mt 4866 2213 itr l2 st rs sv np [40] 20 sd 4390 1209 itr mt 4390 1838 itr l2 st rs sv np [40] 20 sd 4390 1209 itr mt 4848 2213 itr l2 st rs sv np [40] 20 sd 4856 2213 itr mt 4883 1372 itr l2 st rs sv np [40] 20 sd 4874 1372 itr mt 5251 1968 itr l2 st rs sv np [40] 20 sd 4848 4457 itr mt 4426 3604 itr l2 st rs sv np [40] 20 sd 4436 3628 itr mt 4848 3896 itr l2 st rs sv np [40] 20 sd 4848 3896 itr mt 4848 4470 itr l2 st rs sv np [40] 20 sd 4436 3616 itr mt 5063 3382 itr l2 st rs sv np [40] 20 sd 5687 4411 itr mt 5695 3896 itr l2 st rs sv np [40] 20 sd 5058 3371 itr mt 5687 3874 itr l2 st rs sv np [40] 20 sd 5695 3896 itr mt 5704 3125 itr l2 st rs sv np [40] 20 sd 5058 3382 itr mt 5714 3102 itr l2 st rs sv np [40] 20 sd 5678 2553 itr mt 5704 3102 itr l2 st rs sv np [40] 20 sd 5256 1968 itr mt 5695 2575 itr l2 st rs sv np [40] 20 sd 5695 2575 itr mt 5714 1781 itr l2 st rs sv np [40] 20 sd 5714 1792 itr mt 6009 2260 itr l2 st rs sv np [40] 20 sd 6019 2260 itr mt 6755 2693 itr l2 st rs sv np [40] 20 sd 6763 2693 itr mt 6719 1792 itr l2 st rs sv np [40] 20 sd 6719 1792 itr mt 5731 1781 itr l2 st rs 6 sw sv np [] 0 sd 2845 5326 itr mt currentpoint translate np 0.987 1.000 scale 0 0 38 0.000 360.000 arc sem gs 0.100 sg ef gr st rs 12 sw sv np 2669 5149 itr mt 3021 5149 itr l2 st rs sv np [40] 20 sd 2669 4958 itr mt 3021 4958 itr l2 st rs /Ich 256 array def StandardEncoding Ich copy pop /bullet/paragraph/section/dieresis/tilde/ring /circumflex/grave/acute/quotedblleft/quotesingle /ellipsis/endash/emdash/guilsinglleft/guilsinglright /quotedblbase/quotesinglbase/quotedblright/OE/oe /Ydieresis/fi/fl/dagger/daggerdbl/Ccedilla/udieresis /eacute/acircumflex/adieresis/agrave/aring/ccedilla /ecircumflex/edieresis/egrave/idieresis/icircumflex /igrave/Adieresis/Aring/Eacute/ae/AE/ocircumflex /odieresis/ograve/ucircumflex/ugrave/ydieresis /Odieresis/Udieresis/oslash/sterling/Oslash/florin /aacute/iacute/oacute/uacute/ntilde/Ntilde/ordfeminine /ordmasculine/questiondown/exclamdown/guillemotleft /guillemotright/Aacute/Acircumflex/Agrave/cent/yen /atilde/Atilde/currency/Ecircumflex/Edieresis/Egrave /dotlessi/Iacute/Icircumflex/Idieresis/Igrave/Oacute /germandbls/Ocircumflex/Ograve/otilde/Otilde/Uacute /Ucircumflex/Ugrave/macron/cedilla/periodcentered Ich 127 97 getinterval astore pop /Ienc { /ncs Ich def /nfn ed /bfn ed /bfd bfn findfont def /nf bfd maxlength dict def bfd{exch dup dup /FID ne exch /Encoding ne and {exch nf 3 1 roll put}{pop pop} ifelse }forall nf/FontName nfn put nf/Encoding ncs put nfn nf definefont pop}bdf /IencO { /ncs Ich def /nfn ed /bfn ed /lnw ed /bfd bfn findfont def /nf bfd maxlength 4 add dict def bfd{exch dup dup /FID ne exch /Encoding ne and {exch nf 3 1 roll put}{pop pop} ifelse }forall nf/FontName nfn put nf/Encoding ncs put nf/PaintType 2 put nf/StrokeWidth lnw put nfn nf definefont pop}bdf /IencSO { /nfn ed /bfn ed /lnw ed /bfd bfn findfont def /nf bfd maxlength 4 add dict def bfd{exch dup /FID ne { exch nf 3 1 roll put}{pop pop} ifelse }forall nf/FontName nfn put nf/PaintType 2 put nf/StrokeWidth lnw put nfn nf definefont pop}bdf /Helvetica-Oblique /Flfon6 Ienc [121 0 0.00 121 -12 -89] /Flfon6 cfnt 3147 5321 itr mt 0 45 itr rt (Encapsulator/Decapsulator) show 3147 5155 itr mt 0 45 itr rt (Virtual Network A) show 3147 4964 itr mt 0 45 itr rt (Virtual Network B) show 6 sw sv np [] 0 sd 2748 4348 itr mt currentpoint translate np 0.987 1.000 scale 0 0 475 55.018 124.982 arc sem st rs 3147 4791 itr mt 0 45 itr rt (Common Routing Space) show rs end %%Trailer %%DocumentFonts: Helvetica-Oblique %%EndDocument end IT 4455 9681 P (Fig.) S 60 J ( 4.) S 60 J ( ) S 60 J ( Virtual) S 60 J ( Networks) S 60 J ( Example) S 1440 10641 P (Each) S 100 J ( Encapsulator) S 101 J ( shown) S 100 J ( has) S 101 J ( an) S 100 J ( virtual) S 101 J ( interface) S 100 J ( on) S 101 J ( one) S 100 J ( of) S 100 J ( the) S 100 J ( virtual) S 100 J ( networks.) S 100 J ( ) S 100 J ( The) S 100 J ( lines) S 1440 10881 P (represent) S 83 J ( individual) S 84 J ( links) S 83 J ( in) S 84 J ( the) S 83 J ( flows) S 84 J ( that) S 83 J ( connect) S 84 J ( each) S 83 J ( member) S 83 J ( of) S 83 J ( the) S 83 J ( virtual) S 83 J ( network.) S 83 J ( ) S 83 J ( Note) S 1440 11121 P (that) S 73 J ( new) S 74 J ( links) S 73 J ( could) S 74 J ( be) S 73 J ( added) S 74 J ( between) S 73 J ( any) S 74 J ( points) S 73 J ( as) S 74 J ( long) S 73 J ( as) S 74 J ( the) S 73 J ( two) S 74 J ( entities) S 73 J ( are) S 74 J ( visible) S 73 J ( to) S 74 J ( each) S 1440 11361 P (other) S 108 J ( in) S 109 J ( a) S 108 J ( common) S 109 J ( Encapsulation) S 108 J ( Space.) S 109 J ( ) S 108 J ( The) S 109 J ( routing) S 108 J ( within) S 109 J ( the) S 108 J ( virtual) S 108 J ( network) S 108 J ( would) S 108 J ( be) S 1440 11601 P (handled) S 92 J ( by) S 93 J ( the) S 92 J ( encapsulation) S 92 J ( mechanism.) S 92 J ( ) S 92 J ( The) S 92 J ( programming) S 92 J ( of) S 92 J ( the) S 92 J ( routing) S 92 J ( tables) S 92 J ( could) S 92 J ( be) S 92 J ( a) S 1440 11841 P (variant) S 60 J ( of) S 60 J ( any) S 60 J ( of) S 60 J ( the) S 60 J ( currently) S 60 J ( existing) S 60 J ( routing) S 60 J ( protocols,) S 60 J ( an) S 60 J ( encapsulated) S 60 J ( OSPF) S 60 J ( for) S 60 J ( example.) S 1440 12321 P (With) S 104 J ( this) S 105 J ( in) S 104 J ( mind,) S 105 J ( it) S 104 J ( would) S 105 J ( be) S 104 J ( possible) S 105 J ( to) S 104 J ( have) S 105 J ( special) S 104 J ( encapsulation) S 105 J ( gateways) S 104 J ( with) S 105 J ( virtual) S 1440 12561 P (interfaces) S 100 J ( on) S 101 J ( two) S 101 J ( virtual) S 101 J ( networks) S 101 J ( to) S 101 J ( form) S 101 J ( an) S 101 J ( entire) S 101 J ( virtual) S 101 J ( internet.) S 101 J ( ) S 101 J ( This) S 101 J ( is) S 101 J ( the) S 101 J ( role) S 101 J ( of) S 101 J ( the) S 1440 12801 P (Encapsulators) S 60 J ( joining) S 60 J ( Virtual) S 60 J ( Network) S 60 J ( A) S 60 J ( and) S 60 J ( Virtual) S 60 J ( Network) S 60 J ( B.) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10033 14640 P (Page) S 60 J ( ) S (14) S 0 12 F PE 1440 1680 P 24 12 F (RFC) S 60 J ( 1241) S 5035 1680 P (Internet) S 60 J ( Encapsulation) S 9860 1680 P (July) S 60 J ( 1991) S 1440 2160 P 0 12 F 24 12 F B (E.) S 60 J ( Encapsulation) S 60 J ( and) S 60 J ( OSI) S E 1440 2640 P 0 12 F 24 12 F (It) S 90 J ( is) S 91 J ( intended) S 90 J ( that) S 91 J ( the) S 90 J ( encapsulation) S 91 J ( mechanism) S 90 J ( described) S 91 J ( in) S 90 J ( the) S 91 J ( memo) S 90 J ( be) S 91 J ( extensible) S 90 J ( to) S 91 J ( other) S 1440 2880 P (environments) S 121 J ( outside) S 122 J ( of) S 121 J ( the) S 122 J ( Internet.) S 122 J ( ) S 122 J ( It) S 122 J ( should) S 122 J ( be) S 122 J ( possible) S 122 J ( to) S 122 J ( encapsulate) S 122 J ( many) S 122 J ( different) S 1440 3120 P (protocols) S 60 J ( within) S 60 J ( IP) S 60 J ( and) S 60 J ( IP) S 60 J ( within) S 60 J ( many) S 60 J ( other) S 60 J ( protocols.) S 1440 3600 P (The) S 104 J ( key) S 105 J ( concepts) S 104 J ( defined) S 105 J ( in) S 104 J ( this) S 105 J ( memo) S 104 J ( are) S 105 J ( the) S 104 J ( mapping) S 105 J ( of) S 104 J ( a) S 105 J ( header) S 105 J ( to) S 105 J ( a) S 105 J ( Flow) S 105 J ( ID) S 105 J ( and) S 105 J ( the) S 1440 3840 P (mapping) S 69 J ( of) S 70 J ( fields) S 69 J ( in) S 70 J ( the) S 69 J ( original) S 69 J ( header) S 69 J ( to) S 69 J ( the) S 69 J ( encapsulating) S 69 J ( header.) S 69 J ( ) S 69 J ( Special) S 69 J ( mappings) S 69 J ( between) S 1440 4080 P (protocols) S 117 J ( would) S 118 J ( have) S 118 J ( to) S 118 J ( be) S 118 J ( defined,) S 118 J ( i.e.) S 118 J ( for) S 118 J ( the) S 118 J ( QoS) S 118 J ( bits,) S 118 J ( and) S 118 J ( some) S 118 J ( sort) S 118 J ( of) S 118 J ( translation) S 118 J ( of) S 1440 4320 P (meanings) S 60 J ( carefully) S 60 J ( crafted,) S 60 J ( but) S 60 J ( it) S 60 J ( would) S 60 J ( be) S 60 J ( possible,) S 60 J ( none) S 60 J ( the) S 60 J ( less.) S 1440 5040 P 0 12 F 8 12 F B (F.) S 67 J ( Security) S 67 J ( Considerations) S E 1440 5520 P 0 12 F 24 12 F (No) S 85 J ( means) S 86 J ( of) S 85 J ( authentication) S 86 J ( or) S 85 J ( integrity) S 86 J ( checking) S 85 J ( is) S 85 J ( specifically) S 85 J ( defined) S 85 J ( for) S 85 J ( this) S 85 J ( protocol) S 85 J ( apart) S 1440 5760 P (from) S 63 J ( the) S 64 J ( checksum) S 63 J ( for) S 64 J ( the) S 63 J ( header) S 64 J ( information.) S 63 J ( ) S 63 J ( However) S 63 J ( for) S 63 J ( authentication) S 63 J ( or) S 63 J ( integrity) S 63 J ( checking) S 1440 6000 P (to) S 76 J ( be) S 77 J ( used) S 76 J ( with) S 77 J ( this) S 76 J ( protocol,) S 76 J ( it) S 76 J ( is) S 76 J ( suggested) S 76 J ( that) S 76 J ( the) S 76 J ( authentication) S 76 J ( information) S 76 J ( be) S 76 J ( appended) S 76 J ( to) S 1440 6240 P (the) S 71 J ( Encapsulated) S 72 J ( Datagram.) S 71 J ( ) S 72 J ( Information) S 71 J ( regarding) S 72 J ( the) S 71 J ( type) S 72 J ( of) S 72 J ( authentication) S 72 J ( or) S 72 J ( integrity) S 72 J ( check) S 1440 6480 P (in) S 60 J ( use) S 61 J ( would) S 60 J ( have) S 61 J ( to) S 60 J ( be) S 61 J ( included) S 60 J ( in) S 61 J ( the) S 60 J ( flow) S 61 J ( management) S 60 J ( protocol) S 61 J ( which) S 60 J ( is) S 61 J ( used) S 61 J ( to) S 61 J ( distribute) S 61 J ( the) S 1440 6720 P (flow) S 60 J ( information.) S 1440 7440 P 0 12 F 24 12 F B (G.) S 60 J ( Authors') S 60 J ( Addresses) S E 2160 7920 P 0 12 F 24 12 F (Robert) S 60 J ( A.) S 60 J ( Woodburn) S 2160 8160 P (SAIC) S 2160 8400 P (8619) S 60 J ( Westwood) S 60 J ( Center) S 60 J ( Drive) S 2160 8640 P (Vienna,) S 60 J ( VA) S 60 J ( ) S 60 J ( 22182) S 2160 9120 P (Phone:) S 60 J ( ) S 60 J ( \(703\)) S 60 J ( 734-9000) S 60 J ( or) S 60 J ( \(703\)) S 60 J ( 448-0210) S 2160 9360 P (EMail:) S 60 J ( ) S 60 J ( woody@cseic.saic.com) S 2160 9840 P (David) S 60 J ( L.) S 60 J ( Mills) S 2160 10080 P (Electrical) S 60 J ( Engineering) S 60 J ( Department) S 2160 10320 P (University) S 60 J ( of) S 60 J ( Delaware) S 2160 10560 P (Newark,) S 60 J ( DE) S 60 J ( ) S 60 J ( 19716) S 2160 11040 P (Phone:) S 60 J ( ) S 60 J ( \(302\)) S 60 J ( 451-8247) S 2160 11280 P (EMail:) S 60 J ( ) S 60 J ( mills@udel.edu) S 1440 14640 P (Woodburn) S 60 J ( &) S 60 J ( Mills) S 10033 14640 P (Page) S 60 J ( ) S (15) S 0 12 F PE PSe