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About this RFC

Details

Date published

May 1969

Authors

G. Deloche.

DOI

https://doi.org/10.17487/RFC0009

Format

PDF.

Cite this RFC

TXT, XML, BibTeX.

Errata

RFC 9 Errata

RFC 9: Host Software

G. Deloche

Unknown

RFC Tips

Page 1: G. Dc1oche , U.C.L.p ,
1 i':1ay 1969
.,..

Page 2: 1. Introdu ct ion
2. HOST-Hosrr Prot o col
2.1 Logic al Li.nks
2.1.1 Pr-Imar y
2.1.2 Aux il iary
2.2 Link Es t ab Ll sbment
2.2.1 G~ner al Proc edur es
2.2.2 Exanp'le
3. Net,..lor f~ Service Calls
3.1 List of Service Call s
4. Data Struc t ure
4.1 II HO ST" Tab I.e
4.2 "LWK" TabLe
4•3 "U S E ~" TabLe

Page 3: ---
':. "
..
.1 . Introduc tio~
'fius paper conc entr-a tes upon t he HOST - I-L)'ST d.l.a'logue proc edure,
rChapter 2 d esc r- Ib e s t ile lOGica l Lin ks ccnn ec t L..l g t he HOST J and th e ..:2.''/ da t a
are exchanged ov er t h ese Li. nks ,
The emphasis of Chapter-a 3 J 11 J an d 5 is on sof't:.. rar e or-gan.i z atl on c;. cl d at a
structure.
Figure 1 hiSllights t he di fferent p~c-sr21:lS Lnvol ved in a HOS'l'.

$Page 4: - - - - ( ' " i .;;" ' .::' .?-.. -. '/~ . . - -" .-:;'- - -- ' <,3 ':..:;- .. -' --, I Ii, •.f... I I J' /' :...--r I ~ ~ _ _Vl_ ', m\,~- - - - - , , r-, K~ ~.-! i7"\~, -r l" h ~ ~:l l . ' , 10;) '0 c Ii \ :~ -r ~ : .: .....). c:. I -' ..' i :'J ~ : t,J" II --- -~'>.. ;J,... o,J , i I ~.. ;;J ... e-P 1.J' f : cr i-c' V' I .j :; ,,:- II ("j :r rt'\ ' I? .... o , I (? \' OTJ . ", ' ~ I - I , J t .... vf;t .5 iI' -- ,;Q I ; "'. " e: s~ ;' ::. \ ' ' I \1" 1- ~ - ~ I! ~ ~ ~ ir - ...? I ::.J:L I ! c:: z: o ...._ J :;,.... I0 ~-- I - ' I Ii ..C' ~ ~ -- ?; r -'· t. ... V" -I :;-;- 'I. ~ o-. I I; > c:., ~ - J c .., ~ X 1...- i --.. : L ...." :1 x ~[!J 'I r I I c-: ;.~ - 0~ :A- 5 :S ,,- .; ... t.. z, ,; ~. C-' ~_ - - .- . . ~ l r f -- <:r 3 ~11\" ~- -' 7 c> ~ If\- - .-- -; ," ~ ~ -----:> --,'-...... J ~) _" =..!2 Q ~~ I ;:..=: _? c::-r ~ .C. r; c-,:' ~ r . J " 7> ~ "FJ ~- . - ~ ':i ~ J S-' . ~ s: I .'F ;:: :t P .:D ,j '--'" --. -- - - -- ~ J . __.-- - =:. :-_~- - - , _ I -:. cd \-0/.) --r. "II_ I o .:> i- ~ ."' . ...:.,. r· (j . 2.. I' f ~ ~~ .v :;> ;.,., i '( _ ----:. :: A: i I. ) . I I o I ;_ __ __ .. _ _----' ! 1 'I' _. .. I -c:: I I -,o r:, r . .:{i;')" '7... .:. -:) .... . :~ -/ ) l ~• •.,: . I' 1 5 /$

Page 5: 2. HOSl'-HJST Pr'c t c co L
= '-- .;..-=-= -"= -=:::.:= =
2.1 ' Lo ~i c c l Lir~ s (~i bJre 2)
~-- - - - --
Any n·I? C:L'1 be v.L evre d as 2.l1 Lnt erf'ace be t we en a lo c al ce nt er and the
t.runk net wo r k, Lo ca lly J an r.::P may se r ve up to four HOS Ts; for eac h
of th em :!.t pr ovi de s 256 l o gic al link s to an y r-e mo t e EOST .
Ho wever' J bet ween an ]].1P and a l l t he ot her niP s no mor-e t h an 64 li nks
may be in us e s.imu'It anecus Iy , In ot h er wo rds J a HOSrr di e.lo Sru in S
with a re mot e EOST c all c on sid er its l oca l I:·IP a s a svd t chi.nx cent e r
offerin g 256 1:L'1 8 S t o t he r-emot e HOS rr, but onl y 64 can be 3.C'ti va t ed
at a t~e. (If 2. loca l cen ter inc luj e s n HOSTs , 64 s houl d be shar ed
amount t he n EOST' s ) .
The 256 Logf.c a.l Lin k s c onne ct in g t';, IO EOS'r s C211 be d ist in GU i s hed a s
fo110 ',.: s:
Link 0 has a s pe ci al s t atu s. It is ' t he ce n t rol lLllk (c o nYlec t i on
' r eque s t s , s t a tu s re po rt of 2.l1y ki nd ••• ).
The 255 ot h er s c an be u s ed e i th er as 2£.! rr,:::.r y lin k s, i.e., "tel et ype
Llke" co nn e ct i on s, or as a U:<ili2- 11r.k ;.; fo r file tr ans mi s s i o n.E1~
2.1.1 Pr WE.r V Li nks Fe at ur es-- ----'--_. .
A pr-Imary lin.%
* is t he f ir s t l i nk est2.b lishe d f or a HOST -EOST tr an s ::1i ss io n.
* is a "T'l'Y- lik e" conn ect i on that i s:
ASCI I Ch Cl" 2.ct 2r 3 ar e tran 3mit ted .
Ec ho s are ~):~ner e.ted by t he r-erno t e HOS'1' .
The r'e tnot e HOS'l' s can s for b reak char-ac ber-,
The t.r-ansr.tlas l on is s l.ow (l es s t h an 20 ch ar ac t er-s p er se cond ) .
~ is mainl y us e d for' t.r-ansmi.t t.Lng cont r ol CO:T:Tl.:::""1d 3, L, e. j fo r
Log-d.n to the r e r;-.o te EOST ope r-at lng sys t em••
* prov l d ~ s s pc c ta l b uffer in G t e chn l q ues for' 5 1 0': ;, sh or-t
t.ran smis al o n.
2.1.2 A ~ ( il i 2~ Y L1D~s ~ e ~ tur 2S
An aux ili ar y l i nk
* is us ed f or tr2l1 s ~:,d.s3ion of larGe '1 01'.1.;::=s of d at a .
* is eat ab l t sh ed In par'a 'lLeL to the priJ-:-:':lr y li nk
* can be' es t ab lis hed on l y if t he fo l lo ~..linG co ndi t i ons ar c
fulfill e d:
user p rc cr ;.:u:,-'3 , at t h e t wo ex t.rernl.tl es , mus t bo th r equi r e
its operrl n g,
ii is us ed f o r el t he r 'o5.!1 2try or c har a c t el' t.r an sml.as.ion .

$Page 6: 2.2,1 Gen er al Pr-oce dures Eac h - HOS~L'( X) user ,,;it 1 r-escect t he foll O\' :i nG pr oc ed ure f'or cc crcun l.cat.L ng \'i i t ~ l iIOSI' ( Y) A, 1..'.,. t-,, 1-) i l' sh ~ O""' ;' 1 '~ V" 1 ] i nk "' 0 1.[(\C'P (Y )(a) ~,:) v...-l. _ v ( ... l.. . _ ., _ . . _ c.. L. . ...<.....U _ • A pr irnar y If[l1·: i s e :.; t aSTi s hed to H00T ( Y) t hr-ough the control lin k O. The conn ect Lon is t h en i n a pre - loc -i n state, i.e., th e re~~ te HOST exp ec ts its st and ar d l OG-in proce d ures. (b) Lo ~- i n Se o ue n~e St ar:ct'2;:'c f .sC.:l l- char a ct e :-- s are sent.Zrece lv ed ove r th e pr- Imary Li. nk, LI1 t h at ':ray , t he EOST(X ) us e r 5 2.Q1 3 in to r e ~o te HOS T(Y) by u si ne it s s t a~ dar d 10 g- LI1 proce dures . (c) Est a bli sh an P..UXi 1. i.9.:" .~ Li.n k t o HOST (Y ) ~'his es t :~Sl is h- ll e! :. s!7I U: 3t E e-e x ec ut e j by b ot h extr e mit i e s . As in (a), this i s done by us i ng t he cont r ol l i nk 0, (d) __ . _ _ _ _ _ J' _Se nrl/ Pe ce 'ive ':'ext over A.uxili21"! l i n :':: 2.2,2 E x~p;~. Ff.gur-c 3 f'ocus e s on t he d at a e xch an ged over t he lin ks dur-Ing a HOST(X)-EOST( Y) di alo ~J e. h t.h .... 1 " 4' .~. 1-' 81-100'-'1"('() as .1"8 n et vr or-x lOenC ll.l cn .... a.on • HOST(Y) has t he n et wor k identifi catio n 5. r:$

$Page 7: ·* (3) and (4) con st Ltut e e. tr lvi.:ll ex a mp'le of a 106- 1.'"1 -pr oced ur e - See re mark 2 be Ic :.. : *(5): hOST en , t2.l ~:i.n E; to t he ope r-at ing sys t c;n of HOST( Y), req~ests f or U~S A . . ~5A is sUD~ose d to be a us er applicatic~ pr-ogr-am in HOSrI' ('1) • *(6) and (7) con st itute tr. e a '..lxiliary Link est.ab Li.sh..rn ent , After (5) 2...'1 aux .lLi.ar y link should be est a blishe d. This is done by H0 3 r~1(X) s in ce it has the hicher iden ti ficati on nurrber: in net:..ror k, e.e't 8 agatns t 5. 'The procedure is very much lik e (1) and (2) . *(8): HOS'I'(X) trans mits a "file" to URSA. ':ihe t.r-ansml ss ion is done over lLj}~ 25 ~~ich has just been established. *(9): HOS'l'(Y) ansvrer-s bac k with a "file" over link 25. And the dialozue Goes on ••• * 0): HOS'I'(X) frees t !1C links he has establish ed H I' : End of t.ransmi ssf.on (ASCII c haracter). o 0; (2): Nurro e r: of link s '..ra nt. ed to be closed C3 JI~S C I I cn aracter) { 0'.{D8) Q>~)~): Link identific aticn nurrber (ASC II char -ac t.ers ) *(11) HOST(Y) ackn ow.ledges back as in (2) t (7). Remar-k 1: 'I'he fiGll!'e 3 dcesn t t Sh O'.., the headf.ng of each messa3e \~hich ~ r2 of cour s e tra~s ~~tted over th es e l~~s. The char-acter-a rep r es ent.ed on eac h lin e sh ould b e vl.eve d inserted in the t2 Xt zo ne of a se s 3?-s e . Remark 2: Th es e c.iarac t er-s - s ee (3) and (4)- Ca..T1 eit her be t.r-ansml t.t.cd one at a t irr e over the line (e ach chara c t er consti t.ut e s t he tex t of" ,., r- n ", ,'''''''''::» 0"'" be o ac ked bef'or'e~ . _ v v_ v ... .l.__ l... J. <.,;;,. 1 1~ ~ ;') .:..J ~ "" 2) _ ... ~ . : \, ~ _.£.l::;,.; tran s :nis sio n by t he u ser co 'rrnurrl.cat.L on pr c gr ani , In eith er case , the r-erno t e EOST can c cns lder t he link as a noroat tele ty pe (Sear-cas br-e ak lng cher-act er-s t p rovi de s eellos ••• ). Remark 3: In (2), (7), or (11), HOST(Y) can an s wer' qz:. cl ~ a negat l ve ~""r>10 · "11,", r; (:"' ·" ""Tl nY'.L- ch ar ac t.er- r.-TW' ·l' nst e ad of ,'f.r' ;'-".... ....~ ...... ...... z .. l . c:...: U . :':- . I .'Y 111", ~ J. u....:.. I.... ... :, 1 ~ :- _ ·lt. ) ~ ....0:. ...'...... • .. 'l. .,J! \ 1 • .1 f'or- m'''' ~ ,.... ~ . ~ "'- ~~ ., - '''~ . ~ ---; ad t r s - ,...,' ~~ - ~ r O <::: 'I' ( '-r )Th 1S,' 0_ 1 ~'1Y v ~ l OI.. ;") _ :'::.:. .,0 )"1..:> ~ l , ,,. 1 :...::> 0 ,,- _ ~ = '1 " ,; l.l..::> ; lJ.. \.. d , 1. oJ \ J, c.;. ~~ __ ~ , ': e ,", .L- r,'.- , 1l .. ~ - ; "'-0 ._ v...... Tnewant s................ to 0 :1':' __"'·....,1J. "" l i n".... · ,l ~..!..' .-',.....:....fl . ; .. ~ v ~_ .. # ·C' "C. J and ..... f o ...." ·...., .i. .L_ -:.....L - __ ~ ~........... '" meS S 2.G e could b e ~. l@ ':.'he re ~IQ..\ is a c har ac t er' Ind f.c at in g '.i"t:: y tI 1'2 p! ' e '/i oiJ :~ blo ck ha s b ee n r e f us e d. Up on rece -· ·v - i r l i..~~ · ba ck ~su ch nerr~:: atc. L,, i""":"ve !'lc ':\ .- n r...:"' Jl ,, \ l--·A L./ ' "-''-'c>n ' - .::>,~ T""j,. ....- .: .~ ' {l' ll...:.. - c; ...... _'\. .i. .L ~ 0. L ~ · ~ '': L. ~ ':1\ ) C::' l-: ( ' ( ) : repeat its me:3S 2.:e unt Ll, EC3T( Y)" ac cept s it. An emer-gen cy proc edure '.. .. ill t ak e pl ac e if teo r:Dn~~ succe s si ve W\ K occ ur.$

$Page 8: - - - ----- , ,, \ \ \ ; / -~ - - - -- / I / Co ' '' ''' .) ll :'") ,,-,- \ 'J r-: c , 'I't.:.\1...,; .: -.' , 1 \ ' , . , \ i - ~ • ~ 2-5 G ( I I ( " I • ; 'I .' ! " . " . I _l. -: ; .~ ":a... .;/ )\ ... .' .__ ........ -I ...... . ~ ' \ .:. " I . . ,. ,. .I , ,. I '- 0 " I \ , - ~ \ .:. . • <> ! I r: , '\ I I 1..• I -. ~ , (\ o - ( J ,I 4, .::- .\. ., ' , f F tC\ I r-.,," c" r~ i. G c- c~ t .( ':" r ' t... ~ r ; .. -=- "' / II t I I \ u$

$Page 9: . . t ~· j . . ' r ~ ( ,w :- '..,\ 1 . Ii'.... ...., ,'\ r , , I" l!'" ..I~ j " i " \ \ '. ~\ C)....,._ -- .. ._- -. _- -- -- - - - ---- -- - - ' -:' ~ r: ---:"\ ( -'\ rr- : r: . -;:-. ' -.- . .': " r 1( ' -: '. r ., . : ~ .: . I I (' ') " ' r: '' . , . '-'- L I , i . .... f'i " I/ " : ' . dJ '1 . \ t..) . , I @ __'1 . ~ > ~ > \-;»: \ , . _,. , • •. . '- . ' ' .' r '. . ,"" L' \ .. ,,-l < \',,-\ 1\ t...) . - - - - - -- - - - - - -- -~ / '-'" .: ' . ' ,....-' f \ / , ; \' : " : . .,~ ..... , t ,:-...... ; I . \ . J \ • '\ • I ' ~ ~../ ~ ..:... a / ' _ "'_ ~ i .' I"'! ((J i I.\. '" '\ :. ~ o' ::-- =- '-'-- - - - - ----- - - ------ _ .:::: -.( !• ... / , "r " ; . \ .: , -, -, , . .... /~ " " . _ ": ' " _." ..... ...... ~. ' r , I ...-' ~ - ~ ". \ (.$

$Page 10: -, \ I . ) - - --- - - - - - - - - - - - - - - - - - - - -$

$Page 11: 3. ~ I= t ~'; (j!" ~ ': 3 ~~r -:/l~ c C ~1=- 3 ==---:::.::--:-:..: .:::::. -=.;:.:..~~--_...=--=---= = A us er pr c gr em a c ce sa ec t ~l e t~ ,::;t ~/; cr i ( f 2. c "i. l i -:i e s (lir1 1-: c c t a..b l i s ~'L~: _ rJ. t J dat a t r an s rrts s i on ) t··, r r"" c. ,- ;) , ,,, c·--' I- ;e " ce I.Ls T'r.",("i ,::r e xe cut I cn ~ a er'v .l.ce c all"" c...u i 1; L.:.. ....... _ .J ~ ' ..... . _._.'..A;~ v .... _ G _ . ._ ' ,J e \.; _ .._ ~ .... - ', '- -- ... - _ _ tra ps to a mon i t or S (~ I' V :!. C 0 r-c ut in e t ha t in t erpr ets and ex ecutes t h e s er vic e. Con tr o l. Ll t c en :,out c·.:l b::=.:.; l;: to the u ser pro S-::'-' <:'1 ;" . 3..1 Li st of s e l".;i.ce C 2.11 'j at u ~; f :r ' s di sco sa l. (a) Ooen Pri iT. :'.I'.'! Link ----. . ~- - PRII-lI D: User ijent i fic 2.~ion o f' t.he p:d.r.!.'J..ry Ll.nk , HOS'i'I D: Re mo t e EOS·.i.' id e!l'cif ic 2. t i on . BUFl~ A D LJ F\: Buf'f'e; : addr ess for t ho irl CC l.u.rlG measages , nm {Pl'- C O D~: Cede t hat t h e nc'c \· !·.) r: : P:'OCI'c.Sl sho u.ld gi ve t o t he us er P!'OG!'2.:":,,, ::lr:en he i s Lnt.er-rupt.ed becau se a r::ess 3. se has coree b2.C;( . on: Opt Lono S U C:l a s "full e cho" ( f or test in.::; p urp o se }, message re qui r ed aft er succe asf' ul, li nk e stab li s r-:r i;cnt , et c ••• • . Remar k: []: n ot r equi r ed . (b) Ooen aux.i l i ar v l i nk -'--- -- - ----- OP.... N"U-X(" ..·( I lJ n"- i Tr1 P' Tt':'r" r1 O" T' ''''''''') ' :;' '' ( v ....Dc • r o :;ti ' ])l:!.. h Au . , ~ ~ w · , ..l .l }, ~ u i: ~ ' : 'u...t r\ ,l:·H ;\ c l - v ..} z... , ~ . 1 AlfAIO': Us er Lderrt iI' Lcat Lcn of the c.1...:.xi li ar y l i n k. PRE·TID: US0~ i de n ti fica t ion o f a pri ffi~~Y li ; ~. Eefers t o a1 alre ady est a'81i s::.ed 9 r::' r: :3. r: ~: Lf.r.k , BUFFA..lJD:i., Ii rl'?.F'l'- COD E , a PI' S21 ;;e mean ing as abo ve . (c) 'l'r an S ~ : li. 3 3 i c n e ve r 'lTRANSLI NK ( I D, BU?Ff\DDI1 , ' '1 , [ O? T ]) 10: Us er lin k i de n ti fi ca t i o n. Depe nd Lng on ,.. ihich t ype o f 1 i nke 3 ~ · : w e want to t runs mlt J thi s Lde nt .L f'Lca t Lon nu rb er- 'di ll be e qua l to a pr e vi ou sl y de fin e d AUX ID/ PR E-UD . BUFFA-DDR: Data location addr-ess f or tr a ll. s r.1iss ion . N: Dat a byt e s mr:0er f or t r-anscrls.s Lon . aPr' · l ..-l ~u........" .......... .11 a" ""'r1 ........"t-...... c... t- ~~~, n ,.,.._ ....... .:. -....L ...... _ J..... . b In ar y )• ( ch ar-ac t.er .l.i JOot Lor.s..... ._\... JJ, AU .. ) ~ ..... .., . ~c T ',.J '- ..-.o.. ac kn o':ll e c:ge :;:'2:1t s Y'equi:::'c-d ( u t i l i z ~ t i o n of ti.... e 2.ux i U a ry ' l in1-:s in a haLf dup l.ex mcde ) , t r a ce bit , etc ••.• (d) 1, TOO l' I~ V I i nk ' ) ~ ~ ' :1' ~ :> l- "' r ~-: .J,._ _ "7_ l".. _.:.;;_-=..~..:.~-'::.. ":" "7_ i'lDDIFLI N"K (I D, OP1') ID: User l i nk Lden t i f'Lcat Lon (Equa l to e i t h er AU:<ID!P R.l tI1 I D) (e) Cl os e 1in !-:: CLOSS LI J i< (I D, [ OPl I]) 10: Sarr.~ riean lrr; 2. S ao ove , On ': CDJ1 be us ed t o c l os e all t he Ltn ks in U3 e by t he us er-.$

$Page 12: --- - -- 4. Da t e. S t :~ u c t ur e'-- - - -.. -_._ . ... . _--- --.. - -- - -- Tne all oc at.ion and t he managemen t of t he lirl1-: s are ca r r i ed ou t by means of thr ee ta bl e s: A Tabl e S Qrted By HJ3T. A Tabl e Sor-t ed By LIJ'. l!(. A Table Sor t ed b y USER . 4.1 ~S T Ta bl e (Se e Fi ~ure 4) It is a bit-t a bl e ii'1di c2.tins , fer a gi ven r emot e HOST, ',Thi ch l in ks are free. (bit-O means f ree Llnk ) This t able shou ld p ro vi de 25G b it s pe r HOST (25 6 lo gic al l i M 3 possible). At a gi ven t ime no mo r e th an 6 Ll b its can be s et to 1 in t he who l e t a bl e. 4.2 l--L\fK Tab ~';: (See F is ures 4 and 5) This t able co nt a f ns as rna...!1Y sectio ns as links in u se ..FiB;ure 5 describe s t he st r uct lrre of a se ction . Star tin g a'1d r e t r i e v al are c a r ~ l e d out dyTI ~dc ally u po~ U3i nc a has h in g t echn.lque b as ed on t he netw ork link id e n ~ i f ic a t i c n s. US ER Tabl e (See Fi~e 4) 'l'he t a bl e str ucture ~ is t;i ven on Fi:?;U2'e 4. These are as many sections as act ive us er s. Each s e ct i on cont a i ns the us er identifi cat i on (8i ven by the oper- at Lng syst e.n ) 2.-"1d , the i den ti .f ic a t i ons of the lin ks in use b y th is us er-. Not ice t ha t a l i nk ha s t vro ident if ic a t i on s: t hat of t he us er (z i ven as a paz-ameter- in t he OPEN s er vic e ca l l) and t hat of t he netw or-k ( t h at i s a t tr i but ed by the net wor k p roga ';l) . Ttd_s table is hasheJ by us er s.$

$Page 13: - - - - --- - T:'1 e enl. ssf.on f'unc t Lons of t he n et wor k proV 'W,I3 are f u l fll l ed by moni.tor se rv ic e r out I ncs , I n tha t sen se 5 th i s pr 0C-'?J] c an be vi.e-red as be Long ing to the oper-at ing sys t.eu . These Iunct I ons are con ce rn ed ':li t h t he li nk e s t e.bli sh:r.ent s and da t a trans rrd.ssion; the y ar c: 3 t~t ej by th e s e r~lc e c all s pr ev io usly des c ri b ed . Let's ex p lain hovr t h es e r out i n es alloc ate an d manage the links by descr-Ib'ing t he oper a ti on s Lnvo.Lved dur In g t he exe cut i on of t he OPEi'[PRTI ;I routin e. Suppose th a t t he va lu e of t he p ar a raet. er- HOS' l'ID is e qu al to j. (a) j is us ed as an i ndex for th e "HOSl,1I tab Ie to re a ch th e "HOSE j" (b) In " HOS't,j" s ection, He s ele ct th e fir st fr ee link ( F'ir 3t bi t =Q ) e.g., i n bit •. (c) j and i det.errnln e r-es pect Lve l y t he HOST-LIP de s tin at io n and t he net work li nk n umo er , (d) 'l'hl.s j -i V2. J.u'] is us ed as a hash in s code t o op en a new sect ion Ln the link t a bl e. e. g. se ct i on ~. (e) In t hi s s ection 1, t he l in k 10 zone i s fi l l ed up \'Ji t h j - i , t he "link opened by us" and "p r-Imary'' bits are se t to I ·, (Se e Ficurc 5.) (Bernark: It is only when ':1e r ec e iv e bac k t he ackncvr'Iedgerten t message I'rorn t {::~ r-emot e Hc) S'l' .-~ ec F iE~U! '~ 3: ( 2)- t h ::.t t he link i s con sid er ed c .:J r:'pl e t el y est2.bli s fl t ~d . Tnen vie se t t o 1 t he bit "Ltn1, e ~tr "( Jli - ',-, ,... ,1") "lso; n t' j s s e c t i cn -0 • ' ::> ", ... or .... t ne ,..., -, ,.., 2.(\. ..., c;. .__ ~l.~'-A • • .t \. ~ _ ~ !1 . v_ J. -\:J 'l ,t.. . ,Jl,.. .L _ .. J._ ~ ~:~ meter Bllil,'!IDD Va I ue i n t:'e "b uf f er add r ea s z one " , and t he user Iden t I f'Lca t.Lon nurroer , i r.,plic it l :.' Giv c!!, In "t he u ser ID zone Of. (f) Usin G t he user - id cr;t if ic a.t J on n uro e r-, ', jC hash the USER. 'I'ao I e to _open (or f i n d) t he r i gh t m s ec t i o n. \~e upd at e t h i s m sec tion by st.o r-Lng -the us er l i m I D n umb er' ( PHP'LT. D) and t he ne t :·;or';-:: li nk ID n umb er- (L) , (g) ~ ""'Y> e Y"<>~.... YO c ... . ..t:::'" ....o ~ " - - e J,..L.'_ :.- .J":~ .~ t ex t :u ~ • . • _ ...:l ~e::.~ \@ 0)'9'.:- .t ~·, ~~ -} . (h) w~ pr e p ~~e a he 2Ji ns a c cordin~ t o B3:! 3 p~ c i f ic a t io ns ( i n or der to sen d t he r:..=3S:J.:: ~ ove r lin ;: 0). (i) 1,'!e ca lcu l at .e t he EOST che ck sum, (j) He put tOGet he r th e h e2.d i : l~~ , che ckc uu, t ex t by provi di nG mOU'ki ng . (k) ! i I , I I ! II I II I$

$Page 14: . 1. L-'.~"I .~<, I . f .... C.~ ·"" ....,1 ~ ;).;.!z. II 1 L } :,. ~' , , "./1 .,_.,." \' "'!.) ' y' ! () ' I ' ·1L'Y""· ,; \ ,:. :~ . ; J. : ~. , . \ " ' ~ , ... I I ' - ~ I V' ... ...._ . t , c· ( ' . .t- ., ) ""..-- - _ . __ ._ .- . •- "'-- -' - - _ . " <, ",,-- _ . ' --- - , - - - _ . _ .~ .- - ~ "",- - - ./'- - - ...., ".-- _ ::" - - ~~ - - - , _. - _ ...._ - - - - - <, I Tf Trn LWl IOT ! I [ - Un ' : TTT TT t :--n rfl T- - - ~ ---l -.'-y .l '- - --- - - - , "--- - .. I · I .I , i '-- - ~---"" '- -'r~ -y- '- I '--- --..r---- v ~ - ___v__ - - - ~ WI · . i ' I ] : I, I !I ,I I '? Y 'I '(f'f "1"1" 'f T I i.....2>J . ,'I l l i! \If . I .l> I I iI I i I ! . ~ '. 'J I I I -:::\ ~:~ ~: b s : ':L, J - -- I,ll II -I 'II I I, ::\ J . ....s , v t o'-- ' ,· · .. OJ. '.l, _ _ ~. _ -L._ ::\ t ~. 'I:"~ ' ! bi ",,·, 14," I I ! i I I I r \ -::. I \ II '.. \! I~ r: ) t - I I I I : I . ·1I : J I I j, 1/ ~ ~ . . ' , , _ .. '\ 1-1'.1. - .: : .." II _. I I I I', ,', I-- - - - -- -- - - - -- - - - - -- - - - - j , . C( I "'-" I""" I '''' ! ~' O ''') 1 •~ ..... . . . C . ":'i 'I ' I" •• If "' t • .' ~ L ~ \ ~. ") '('-"4 Ii ) - -- --.. J - ~ - ~. : ' ..) ..' : .' ) ,,'" ...$

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RFC 9: Host Software

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In this section

RFC 9: Host Software