HDLC

Data Link Layer: Protokol High level Data Link Control (HDLC) Achmad Ubaidillah, ST!T

S"mber : Hendra#an hend$telecomeeitbacid

Data Link Service% & Connection'oriented %ervice%: memberikan engiriman aket ter"r"t beba% error  %etting'" konek%i: %etting " variable% dan aloka%i b"**er  tran%*er aket: aket +dikema% dlm *rame data link  en"t"an konek%i

& Connectionle%% %ervice  ackno#ledged %ervice  "nackno#ledged %ervice

Se-arah DLL Protocol% & SDLC ' Synchrono"% Data Link Control (./!) & HDLC ' High'level Data Link Control (.S0 1 CC.TT) & ADCCP ' Advanced Data Comm"nication% Control Protocol (A2S.) & LLC ' Logical Link Control (.333 4566) & .S0 77558, .S0 977 Data Link Control

Tie Station HDLC & Primary %tation  mengontrol oera%i link  *rame yg dibangkitkan di%eb"t command  men-aga link logik teri%ah ke ma%ing'ma%ing %tation %econdary

& Secondary %tation  diba#ah kontrol rimary %tation  *rame yg dibangkitkan di%eb"t re%on%

& Combined %tation  daat membangkitkan command dan re%on%

!ode Tran%*er HDLC & 2ormal ;e%on%e !ode (2;!) 
!ode Tran%*er HDLC & A%ynchrono"% /alanced !ode (A/!) 
!ode Tran%*er HDLC & A%ynchrono"% ;e%on%e !ode (A;!)  arang dig"nakan


Secondary Responses

Unbalanced Multipoint link  Commands Primary Responses Secondary

Secondary

Secondary

Balanced Point-to-point link between Combined Stations Primary Secondary

Commands Responses

Responses

Secondary

Commands

Primary

?ormat ?rame HDLC Flag

Address

Control

Inormation

FCS

& ?lag (4 bit) : 5@@@@@@5 & Addre%% (4 bit etendable @B bit): 
 addre%% %econdary

→

& ?rame command → addre%% receiving %tation & ?rame re%on%e → addre%% dari %tation engirim

& Control *ield (4 etendable @B bit) & .n*ormation *ield (variabel): beri%i in*orma%i "%er & ?CS: C;C @B bit ata" 76 bit dikalk"la%i d *ield control, addre%% dan in*orma%i

Flag

/it St"**ing & /it %t"**ing dig"nakan "nt"k mencegah kem"nc"lan ola *lag didalam *rame HDLC & Pengirim akan menyi%ikan ek%tra 5 %etia ditem"i lima deretan @ yg bert"r"tan & Penerima mencari lima deretan biner @ bert"r"tan, -ika dii"k"ti 5 berarti bit %t"**ing → bit dihilangkan & Contoh:  Deretan data in*orma%i: 5@@5@@@@@@@@@@55  Setelah bit %t"**ing: 5@@5@@@@@5@@@@@555

?rame' ?rame HDLC

0era%i HDLC & Pert"karan *rame'*rame: in*orma%i, %"ervi%ory dan "nn"mbered & Tiga ha%e:  .ni%iali%a%i  Tran%*er data  Pen"t"an

SABM

UA

!ata transer 

!ISC

UA

0era%i ada 2ormal ;e%on%e !ode Primary A

Secondaries B, C

B" RR" #" P

&

B" I" #" # B" I" $" # B" I" %" #"F

B" SR'(" $ C" RR" #" P C" RR" #" F B" SR'(" $"P B" I" $" # B" I" )" # B" I" *" #" F B" I" #" +

0era%i ada A%ynchrono"% /alanced !ode Combined Station A

Combined Station B

B" I" #" # B" I" $" # B" I" %" $ B" I" )" % B" I" *" )

A" I" #" # &

A" I" $" $ A" I" %" $ B" R'(" $ A" I" )" $

B" I" $" ) B" I" %" * B" I" )" *

B" RR" % B" RR" )

Protocol DLC Lainnya & Link Acce%% Proced"re, /alanced (LAP/)  /agian dari E6 (.TU'T)  S"b%et dari HDLC (A/!)  Link oint'to'oint antara %i%tem dan node acket %#itching

& Link Acce%% Proced"re, D'Channel (LAPD)     

.SD2 (.TU'T) A/! SeF"ence n"mber %elal" G bit (tidak 7 bit) ?ield addre%% @B bit terdiri dari d"a %"b'addre%%e% %at" "tk device dan %at" lagi "tk "%er (layer diata%)

Protocol DLC Lainnya & Logical Link Control (LLC): "m"mnya "tk %hared medi"m net#ork% (broadca%t media)  .333 456  ?rame *ormat berbeda  Link control dibagi d"a antara medi"m acce%% layer (!AC) dan LLC (di ata% !AC)  Tidak ada rimary dan %econdary (%em"a %tation adalah eer)  D"a addre%%e% dierl"kan: & engirim dan enerima

Protocol DLC Lainnya & PPP (Point'to'Point Link Protocol) & Layo"t *rame "tk PPP: Flag

Address

#$$$$$$# $$$$$$$

All stations are to accept t,e rame

Control ######$$

Unnumbered rame

Protocol

Inormation

CRC

lag #$$$$$$#

Speciies w,at kind o packet is contained in t,e  payload" eg" .CP" /CP" IP" 0SI C./P" IP&

.n'Cla%% 3cer%i%e Pd gb di ba#ah, rimary %tation A berkom"nika%i dengan %econdary %tation /, C dan D mengg"nakan rotokol data link %tandar (mi%alnya HDLC) ada %al"ran d"a'arah hal*'d"le ambar (b) memerlihatkan "r"tan tran%mi%i data antara A dan /, C %erta D dengan mengg"nakan nota%i %ingkat A I 2(S) 2(;) PJ? (A:Addre%%, I:CommandJ;e%on%e, 2(S): SeF"ence n"mber engirim, 2(;):SeF"ence n"mber enerima, PJ?:PollJ?inal) Pada gambar i%i harga A,I2(S)2(;),PJ?

.n'Cla%% 3cer%i%e 6

"ga a%"m%ikan bah#a "k"ran #indo# adalah G (Cat "nakan nota%i A,I2(S)2(;),PJ?)