Tng Vn chuyn
CHC NNG - 1
03/2011
Cung cp knh truyn d liu mc logic gia 2 tin trnh trn 2 myapplication transport network data link physical network data link physical
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Application Presentation Session
network data link physical
network data link physical network data link physical network data link physical
TransportNetwork Data link
Physicalapplication application transport transport network network data link data link physical physical
2
NI DUNGGii thiu Nguyn tc truyn d liu ng tin cy Giao thc TCP Giao thc UDP
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
3
NHC LIsourcemessageM M M M
03/2011
segmentpacket frame
Ht Hn Ht
Hl Hn Ht
application transport network link physical link physical switch
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
destinationM Ht Hn Ht M M
Hn Ht Hl Hn Ht
M M
application transport network link physical
network link physical
Hn Ht
M
4 router
TNG VN CHUYN
-1
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
P2M M
P3Process nhn?Ht D Ht D M
P1Gi n Process?Ht D M D Ht D H n segment M
application transport network
P4
H n segment
application transport network
application transport network
5
TNG VN CHUYN
-2
03/2011
Thc thi end-system Bn gi: thc hin Dn knhNhn d liu t tng ng dng (t cc socket) Phn on thng ip tng ng dng thnh cc segment Dn nhn d liu: ng gi theo giao thc ti tng Transport Chuyn cc segment xung tng mng (network layer)
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Bn nhn: thc hin Phn knhNhn cc segment t tng mng Phn r cc segment thnh thng ip tng ng dng Chuyn thng ip ln tng ng dng (n socket tng ng)6
TNG VN CHUYN
-3
03/2011
H tr
Truyn d liu ng tin cyiu khin lung iu khin tt nghn Thit lp v duy tr kt ni
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Truyn d liu khng ng tin cy
N lc gi d liu hiu qu nht
Khng h trm bo thi gian tr m bo bng thng
7
DN KNH PHN KNH - 1 Dn
03/2011
knh (Multiplexing):
Thc hin ti bn gi Thu thp d liu t cc socket dn nhn d liu vi 1 header Phn
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
knh (Demultiplexing):
Thc hin ti bn nhn phn phi cc segment nhn c cho socket tng ng
Khi
ng gi d liu tng transport, header s thm vo:Source port Destination port
8
DN KNH PHN KNH - 232 bits
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
source port #
dest port #
other header fields
application data (message)
Cu trc ca mt segment
9
DN KNH PHN KNH - 3
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
P26428
P1 P15775
SP: 6428 DP: 5775
server IP: B
SP: 5775 DP: 6428
ClientIP:A
10
NI DUNGGii thiu Giao thc UDP Nguyn tc truyn d liu ng tin cy Giao thc TCP
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
11
UDP - 1
03/2011
UDP: User Datagram Protocol [rfc768]Dch v n lc truyn nhanh Gi tin UDP c th:
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Mt Khng ng th t
Khng kt ni:Khng c handshaking gia bn gi v nhn Mi gi tin UDP c x l c lp Khng c trng thi kt ni
12
UDP - 232 bits Chiu di gi tin (tnh c header) source port # length dest port # checksum
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Application data (message)
UDP segment format13
UDP - 3Application Transport .. U Cc segment n khng ng th t??? U1 M U2 U3
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Application Transport ..14
Mt segment?
UDP - 4
03/2011
Ti sao li s dng UDP?Khng thit lp kt ni n gin:
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
khng qun l trng thi ni kt Khng kim sot lung
Header nh Nhanh
Truyn thng tin cy qua UDP
Tng application pht hin v phc hi li
15
UDP - 5
03/2011
Thng s dng cho cc ng dng multimedia
Chu li Yu cu tc
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Mt s ng dng s dng UDPDNS SNMP TFTP
16
NI DUNGGii thiu Nguyn tc truyn d liu ng tin cy Giao thc TCP Giao thc UDP
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
17
03/2011
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
BI TON
Lm sao truyn ng tin cy???
18
NGUYN L TRUYN D LIU NG TIN CYapplication Bn gi Bn nhn
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
transport
ng truyn tin cy
Nghi thc truyn tin cy
Nghi thc truyn tin cy
ng truyn khng tin cy a. Cung cp dv b. Trin khai dv
c tnh ca ng truyn khng tin cy quyt nh phc tp ca nghi thc truyn tin cy19
NI DUNG
03/2011
Nghi thc truyn d liu ng tin cyRDT 1.0 RDT 2.0, RDT 2.1, RDT 2.2 RDT 3.0
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
PipelineGo-back-N Gi li c chn
20
GII QUYT LI BIT
03/2011
Bn giGi km theo thng tin kim tra li S dng cc phng php kim tra li
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Checksum, parity checkbit, CRC,..
Bn nhnKim tra c xy ra li bit? Hnh ng khi xy ra li bit?
Bo v bn gi
21
GII QUYT MT GI
03/2011
Bn nhn
Gi tn hiu bo
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Gi gi tin bo hiu ACK, NAK
Bn ginh ngha trng hp mt gi Ch nhn tn hiu bo Hnh ng khi pht hin mt gi
22
GIAO THC RDT
03/2011
RDT = Reliable Data Transfer Nguyn tc: dng v ch
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Bn gi
Gi gi tin km theo thng tin kim tra li Dng v ch n khi no gi tin va gi n c bn nhn an ton: nhn c gi tin ACK Gi li khi c li xy ra: li bit, mt gi Kim tra li, trng lp d liu Gi gi tin phn hi
Bn nhn:
Phin bn:
RDT 1.0 RDT 2.0 RDT 2.1 RDT 2.2 RDT 3.023
NGUYN L PIPE LINE
03/2011
Cho php gi nhiu gi tin khi cha nhn ACK
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
S dng buffer lu cc gi tinBn gi: lu gi tin gi nhng cha ack Bn nhn: lu gi tin nhn ng nhng cha ng th t
Gii quyt mt giGo back N Selective Repeat (gi li c chn)24
RDT1.0 : NG TRUYN L TNG
03/2011
Gi thit: knh truyn bn di tuyt i
Khng li bit Khng mt gi tin Bn gi chuyn d liu xung knh bn di Bn nhn c d liu t knh truyn bn di
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
FSM (finite state machine) cho bn gi v nhn
Wait for call from above
rdt_send(data) packet = make_pkt(data) udt_send(packet)
Wait for call from below
rdt_rcv(packet) extract (packet,data) deliver_data(data)
sender
receiver25
RDT2.0 KNH TRUYN C LI BIT - 1 Gi
03/2011
thit: knh truyn c th xy ra li bitchecksum
S dng cc c ch kim tra li
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Lm
sao khc phc khi nhn ra li?
Acknowledgement(ACKs): bn nhn bo cho bn gi nhn c d liu Nagetive acknowledgement(NAKs): bn nhn bo gi tin b li Bn gi s gi li gi tin khi nhn NAK
So
vi rdt1.0, rdt2.0:
Nhn dng li C ch phn hi: ACK, NAK26
RDT2.0 FSM - 2rdt_send(data) snkpkt = make_pkt(data, checksum) udt_send(sndpkt) rdt_rcv(rcvpkt) && isNAK(rcvpkt) Wait for Wait for call from above ACK or NAK udt_send(sndpkt)
03/2011
receiverrdt_rcv(rcvpkt) && corrupt(rcvpkt) udt_send(NAK)Wait for call from below rdt_rcv(rcvpkt) && notcorrupt(rcvpkt) extract(rcvpkt,data) deliver_data(data) udt_send(ACK)27
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
rdt_rcv(rcvpkt) && isACK(rcvpkt) L
sender
ACK/NAK sai???
RDT2.0 - 3
03/2011
Gii quyt:Bn gi gi li gi tin khi nhn ACK/NAK sai Bn gi nh s th t cho mi gi tin Bn nhn s loi b gi tin trng.
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Dng v i
Bn gi gi mt gi tin v ch phn hi t bn nhn
28
RDT2.1 BN GI X L LI ACK/NAKrdt_send(data) sndpkt = make_pkt(0, data, checksum) udt_send(sndpkt) rdt_rcv(rcvpkt) &&Wait for call 0 from above Wait for ACK or NAK 0
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
( corrupt(rcvpkt) || isNAK(rcvpkt) ) udt_send(sndpkt) rdt_rcv(rcvpkt) && notcorrupt(rcvpkt) && isACK(rcvpkt) L
rdt_rcv(rcvpkt) && notcorrupt(rcvpkt) && isACK(rcvpkt) L rdt_rcv(rcvpkt) && ( corrupt(rcvpkt) || isNAK(rcvpkt) ) udt_send(sndpkt)Wait for ACK or NAK 1
Wait for call 1 from above
rdt_send(data) sndpkt = make_pkt(1, data, checksum) udt_send(sndpkt)29
RDT2.1 BN NHN X L LI ACK/NAKrdt_rcv(rcvpkt) && notcorrupt(rcvpkt) && has_seq0(rcvpkt)extract(rcvpkt,data) deliver_data(data) sndpkt = make_pkt(ACK, chksum) udt_send(sndpkt) rdt_rcv(rcvpkt) && (corrupt(rcvpkt) sndpkt = make_pkt(NAK, chksum) udt_send(sndpkt) Wait for 0 from below Wait for 1 from below
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
rdt_rcv(rcvpkt) && (corrupt(rcvpkt) sndpkt = make_pkt(NAK, chksum) udt_send(sndpkt) rdt_rcv(rcvpkt) && not corrupt(rcvpkt) && has_seq1(rcvpkt) sndpkt = make_pkt(ACK, chksum) udt_send(sndpkt)
rdt_rcv(rcvpkt) && not corrupt(rcvpkt) && has_seq0(rcvpkt)sndpkt = make_pkt(ACK, chksum) udt_send(sndpkt)
rdt_rcv(rcvpkt) && notcorrupt(rcvpkt) && has_seq1(rcvpkt) extract(rcvpkt,data) deliver_data(data) sndpkt = make_pkt(ACK, chksum) udt_send(sndpkt)
30
RDT2.1 THO LUNBn gi Thm s th t vo gi tin
03/2011
0 v 1???
Phi kim tra: ACK/NAK sai khng Phi nh gi tin hin thi c th t 0 hay 1
Bn nhn Phi kim tra nu nhn trng So snh trng thi ang ch (0 hay 1) vi trng thi gi tin nhn c
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Bn nhn khng bit ACK/NAK cui cng c chuyn ti bn gi an ton khng?31
C CH TRUYN NG TIN CY - RDT
03/2011
C ch:Checksum: kim tra c li xy ra khng? ACK: bn nhn nhn ng gi tin NAK: bn nhn nhn sai gi tin Sequence Number (1 bit = 0 hoc 1)
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
32
RDT2.2 KHNG S DNG NAKHot ng ging rdt2.1, nhng khng dng NAK Bn nhn gi ACK cho gi tin khng li nhn c cui cng.
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Bn nhn phi thm s th t vo gi tin ACK
Bn gi nhn trng gi tin ACK xem nh gi tin NAK gi li gi va gi v gi ny cha nhn c ACK
33
RDT2.2: BN GI V BN NHNrdt_send(data) sndpkt = make_pkt(0, data, checksum) udt_send(sndpkt)Wait for call 0 from above Wait for ACK 0
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
rdt_rcv(rcvpkt) && ( corrupt(rcvpkt) || isACK(rcvpkt,1) )udt_send(sndpkt)
sender FSM fragmentrdt_rcv(rcvpkt) && (corrupt(rcvpkt) || has_seq0(rcvpkt) ) sndpkt = make_pkt(ACK0, chksum) udt_send(sndpkt)
rdt_rcv(rcvpkt) && notcorrupt(rcvpkt) && isACK(rcvpkt,0)
Wait for 1 from below
L
receiver FSM fragment
rdt_rcv(rcvpkt) && notcorrupt(rcvpkt) && has_seq1(rcvpkt) extract(rcvpkt,data) deliver_data(data) sndpkt = make_pkt(ACK1, chksum) udt_send(sndpkt)
34
RDT3.0 KNH TRUYN C LI V MT - 1
03/2011
Gi thit:Li bit mt gi Checksum, s th t, ACKs, truyn li vn cha
X l?
Gii php: bn gi i mt khong thi gian hp l cho ACK Gi li nu khng nhn c ACK trong khong thi gian ny Nu gi tin (hay ACK) b tr (khng mt) Gi li c th trng, phi nh s th t Bn nhn phi xc nh th t ca gi tin ACK
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Yu cu m thi gian35
RDT3.0 BN GI - 2rdt_send(data) sndpkt = make_pkt(0, data, checksum) udt_send(sndpkt) start_timer Wait for call 0from above rdt_rcv(rcvpkt) && notcorrupt(rcvpkt) && isACK(rcvpkt,1) stop_timer Wait for ACK1 rdt_send(data) sndpkt = make_pkt(1, data, checksum) udt_send(sndpkt) start_timer 36 Wait for call 1 from above Wait for ACK0 rdt_rcv(rcvpkt) && ( corrupt(rcvpkt) || isACK(rcvpkt,1) )
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Ltimeout udt_send(sndpkt) start_timer rdt_rcv(rcvpkt) && notcorrupt(rcvpkt) && isACK(rcvpkt,0) stop_timer
timeout udt_send(sndpkt) start_timer rdt_rcv(rcvpkt) && ( corrupt(rcvpkt) || isACK(rcvpkt,0) ) L
rdt_rcv(rcvpkt)
L
03/2011
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
RDT3.0 - 3
37
03/2011
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
RDT3.0 - 4
38
03/2011
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
RDT3.0 DNG V I - 5
39
RDT3.0 HIU QU - 6Rdt3.0 lm vic, nhng khng hiu qu Vd:bng thng 1Gbps, 15ms end2end delay, gi tin 8Kb
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Usender : t l thi gian bn gi gi gi tin Nghi thc hn ch vic s dng ti nguyn mng40
NGHI THC PIPELINE - 1
03/2011
Pipelining: bn gi cho php gi nhiu gi tin khi cha c bo nhn (ACK)
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Gi tin: sp theo th t tng dn Dng b m bn gi hoc/v bn nhn: Sliding window
C hai gii php chnh ca nghi thc pipeline: go-Back-N gi li c chn.41
03/2011
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
NGHI THC PIPELINE - 2
Tng hiu qu s dng ln 3 ln
42
GO-BACK-N 1 S
03/2011
th t: k-bit window = N s gi tin c gi lin tc khng ACK
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
ACK(seq#): nhn ng n seq#
43
GO-BACK-N: BN NHN - 2
03/2011
Bn gi:
S dng buffer (window) lu cc gi tin gi nhng cha nhn c ACK Gi nu gi tin c th a vo window Thit lp ng h cho gi tin c nht (gi tin u window) Timeout: gi li tt c cc gi tin cha ACK trong window Ch gi ACK cho gi tin nhn ng vi s th t cao nht
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Bn nhn:
C th pht sinh trng ACK
Ch cn nh s th t ang i Gi tin khng theo th t:
Loi b: khng c b m Gi li ACK vi s th t ln nht
44
03/2011
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
GO-BACK-N V D - 3
45
GI LI C CHN - 1
03/2011
Bn nhn:
Bo nhn ring l tng gi tin nhn ng
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
ACK(seq#): nhn ng gi tin seq#
dng b m lu cc gi tin khng ng th t Nhn 1 gi tin khng ng th t
a vo b m nu cn ch Hy gi tin
Bn gi:
C ng h cho mi gi tin cha nhn c ACK Time out: ch gi nhng gi tin khng nhn c ACK
46
GI LI C CHN - 2Bt u bn gi Th t k tip ACK Gi, cha ACK Cha dng khng dng c
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Th t bn gi
Sai th t nhng ACK ang i, cha nhn c
C th nhn c khng dng c
Bt u bn nhn Th t bn nhn 47
03/2011
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
GI LI C CHN - 4
48
GI LI C CHN - 503/2011
Vd:
S th t:0,1,2,3 Window size: 3
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Mi quan h gia s th t v window size???
49
NI DUNGGii thiu Nguyn tc truyn d liu ng tin cy Giao thc TCP Giao thc UDP
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
50
TCPGii thiu Nguyn tc hot ng Qun l kt ni iu khin lung iu khin tt nghn
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
51
TCP GII THIU - 1 TCP
03/2011
= Transport Control Protocol
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
rfc: 793,1122,1323,2018,2581 Point to point
1 ngi gi v 1 ngi nhn
Full-duplex
D liu truyn 2 chiu trn cng kt ni MSS: maximum segment size
Hng kt ni
Handshaking trc khi gi d liu52
TCP - GII THIU - 2 TCP
03/2011
= Transport Control Protocol
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
TCP cung cp kt ni theo kiu dng (stream-of-bytes)
Khng c ranh gii gia cc gi tin S dng buffer gi v nhnsocket door application writes data TCP send buffersegment
application reads data TCP receive buffer
socket door
Tin cy, theo th t
PipelineKim sot lung Kim sot tt nghn53
TCP CU TRC GI TIN32 bits URG: urgent data (generally not used) ACK: ACK # valid PSH: push data now (generally not used) RST, SYN, FIN: connection estab (setup, teardown commands)
03/2011
source port #
dest port #
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
sequence numberacknowledgement numberhead not U AP R S F len used
rcvr window size
checksum
ptr urgent data
Options (variable length)
# bytes rcvr willing to accept
application data (variable length)
54
TCP NH NGHA CC TRNG - 1 Source
03/2011
& destination port
Port ca ni gi v ni nhn
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Sequence
number
S th t ca byte u tin trong phn data ca gi tin
Acknowledgment
number
S th t ca byte ang mong ch nhn tip theo
Window
size
Thng bo c th nhn bao nhiu byte sau byte cui cng c xc nhn nhn
55
TCP NH NGHA CC TRNG - 2
03/2011
Checksum
Checksum TCP header
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Urgent pointer
Ch n d liu khn trong trng d liuURG = trng urgent pointer valid ACK = trng Acknowledge number valid PSH = d liu cn phn phi ngay RST = ch nh ni kt cn thit lp li (reset) SYN = s dng thit lp kt ni FIN = s dng ng kt ni
C:
56
TCP V DHost A Seq: s th t ca byteUser types C
03/2011
Host B
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
u tin trong vngdata
host ACKs receipt of C, echoes back C
ACK: s th t ca byte ch nhn tip theo
host ACKs receipt of echoed C
simple telnet scenario57
TCP TRUYN D LIU NG TIN CY
03/2011
Nguyn tc: dng pipelineBn gi nh km thng tin kim tra li trong mi gi tin S dng ACK bo nhn Thit lp thi gian timeout khi cho gi tin u buffer Gi li ton b d liu trong buffer khi ht time out
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
58
TCP BN GI
03/2011
Nhn d liu t tng ng dngTo cc segment Bt ng h (nu cha bt) Thit lp thi gian ch, timeout
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Nhn gi tin ACKNu trc cha nhn: trt ca s Thit lp li thi gian ca ng h
Ht time outGi li d liu cn trong buffer Reset ng h
59
TCP BN NHN
03/2011
Nhn gi tin ng th tChp nhn Gi ACK v cho bn gi
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Nhn gi tin khng ng th tPht hin khong trng d liu (GAP) Gi ACK trng
60
TCP V DHost A Host B Host A Host B
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
loss
X
time
SendBase = 120 time lost ACK scenario
Seq=92 timeout
Sendbase = 100 SendBase = 120
Seq=92 timeout
timeout
premature timeout61
TCP THIT LP KT NI Thc
03/2011
hin thao tc bt tay 3 ln (Three way handshake)My A My B
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
SYN_RCVD state
ESTABLISHED state
62
TCP NG KT NI
03/2011
Thc hin thao tc bt tay 2 lnclient server
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
close
close
closed63
timed wait
TCP QUN L KT NI
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
TCP server lifecycle
TCP client lifecycle
64
TCP - IU KHIN LUNG - 1
03/2011
Nguyn nhn:
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Bn gi lm trn b m ca bn nhn khi gi qu nhiu d liu hoc gi qu nhanh Window size: lng DL c th a vo buffer
S dng trng window size
65
TCP - IU KHIN LUNG - 2ng dng gi 2K Gi Nhn B m bn nhn 0 4K
03/2011 TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Empty
2K ng dng gi 2K Full Bn gi b kha
Bn gi c th gi n 2K
2K
1K
2K
66
KIM SOT TT NGHN - 1
03/2011
Vn : 1 node c th nhn d liu t nhiu ngunBuffer: gii hn gi tin: n t
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
x l khng kp tt nghn Hin tng:Mt gi Delay cao
S dng ng truyn khng hiu quHost A
lin : original data
lout
Host B
unlimited shared output link buffers
67
KIM SOT TT NGHN - 2
03/2011
Gii quyt trong TCP:RTT
Host A
Host BTTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
Bn gi:
Thit lp tc gi da trn phn hi t bn nhn
Nhn ACK Mt gi tr gi tin time
Tc gi: c 2 pha
Slow-Start Congestion Avoidance68
TI LIU THAM KHO
03/2011
Bi ging ca J.F Kurose and K.W. Ross v Computer Networking: A Top Down Approach
TTMTRANG - BM MMT&VT - KHOA CNTT - H KHTN TP.HCM
69