1 CHUYÊN ĐỀ Các kỹ thuật đảm bảo chất lượng mạng IP Giảng viên: TS. Nguyễn Chiến Trinh Điện thoại: 0915400946 E-mail: [email protected]
1CHUYN
Cc k thut m bo cht lng mng IPGing vin: TS. Nguyn Chin Trinh
in thoi: 0915400946 E-mail: [email protected]
2Ni dung
Tng quan v cht lng dch v (QoS).
Cc tham s nh gi cht lng mng IP.
Cc k thut m bo QoS.
Mt s m hnh m bo QoS.
Cc ni dung chuyn .
3Cht lng mng NP
Network Performance l nng lc ca mt mng (hoc l phn mng) cung cp chc nng lin quan n truyn thng tin gia nhng ngi s dng.
Cht lng mng c o lng thng qua cc tham s c ngha i vi nh cung cp mng v c dng cho nhng mc ch thit k, nh cu hnh, khai thc v bo dng h thng.
NP c nh ngha mt cch c lp vi cht lng thit b u cui v nhng hot ng ca ngi s dng.
4Chat lng dch v QoS
QoS l kt qu tng hp ca cc ch tiu hiu nng dch v th hin mc hi lng ca i tng s dng dch v .
Cc yu cu QoS ca ngi s dng/khch hng: l bng k khai mc dch v ca ngi s dng/khch hng v mt dch v, c th c din t mt cch khng phi l k thut. .
QoS c xut bi nh cung cp: l mc cht lng dch v c mong i cung cp cho khch hng bi nh cung cp dch v .
5S khc bit gia QoS v NP
Tham s QoS
ch yu
Tham s NP
ch yu
Speed
(Tc )
Throughput
(Thng lng)
Accuracy
( chnh xc)
Error Rate
(T l li/ Mt gi)
Dependability
(Tnh tin cy)
Delay
Delay Variation or Jitter
(Tr, Bin thin tr)
6Tham s cht lng dch v QoS (v d 1)
B cc tham s v ch tiu cho cht lng dch v VoBB
STT
Tn tham s Ch tiu
1. T l cuc gi c thit lp thnh cng
95%
2. Tr dch v u cui-u cui 150ms
3. Bin thin tr u cui-u cui 50ms
4. T l mt gi 1%
5. MOS 3.5
6. TDT 1s
7. CST 3s
8. ECT 2s
9. Tr sau quay s PDD 2s
7Tham s cht lng dch v QoS (v d 2) Ch tiu truyn dn HDTV
Tc lung
(Mbps)
(1)
Tr, ms
(2)
Rung pha, ms
(3)
Thi gian li cc i,
ms
(4)
Chu k tn tht
gi IP, gi IP
(5)
Khong tn tht gi, s kin
li/4gi
(6)
T l li gi lung IP video
(7)
8 < 200
< 50 16 < 14 1 1,28 E-06
10,0 < 200
< 50 16 < 17 1 2,24 E-06
12 < 200
< 50 16 < 20 1 5,22 E-06
8Tham s cht lng dch v QoS (v d 2) Ch tiu tng tc thi gian IPTV
V d Loi Tr ln nht, ms
Cc thao tc trn giao din ngi s dng
Cun EGP. Bm nt iu khin t xa VoD cho ti khi ch th trn mn hnh lnh c nhn (v d k
hiu tm dng c hin th)
Tng tc
200
Chuyn knh Thi gian t khi bm nt iu khin t xa cho ti khi knh c
hin th n nh trn mn hnh
p ng
2000
Thi gian khi ng h
thng
Thi gian t khi bt ngun STB ti khi knh c hin th.
30.000
9YU CU I VI CC THAM S NP
L nhng tham s c trng v c nh hng chnh n cht lng mng.
L nhng i lng c kh nng o c
S dng cho mc ch ca nh cung cp mng/dch v vin thng, p ng yu cu nh gi
Ph hp vi cc tiu chun, qui nh ca B v cc tiu chun quc t.
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CU TRC MNG
11
nh gi cht lng theo lp
12
Cc tham s cht lng mng lp IP
Tr truyn gi tin mt chiu.
Bin ng tr truyn gi tin.
tn tht gi tin.
Mc li gi tin.
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Tr truyn gi tin mt chiu IPTD
Tr mt chiu ca mt gi tin c tnh bng thi gian gi tin c truyn i c tr i thi gian nhn gi tin mong mun t c .
Tr gi trn mt ng end-to-end gm 4 thnh phn ti mi nt mng.
A
B
propagation
nodalprocessing queuing
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Tr truyn gi tin mt chiu IPTD
Tr x l: kim tra bit li, xc nh tuyn ra.
Tr hng i: thi gian i trong b m truyn i, ph thuc vo tnh trng tc nghn ca mng.
Tr truyn dn: thi gian truyn gi tin.
Tr truyn lan: tr truyn thng tin trn ng, tnh theo khong cch ca ng nh tuyn.
200 km -> 1ms
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Bin thin tr IPDV
Bin ng tr gi l chnh lch tr gia 2 gi hay gia mi gi so vi mt i lng tham chiu nh tr trung bnh hay tr ti thiu trong mt chui gi c cng ngun v ch.
Bin ng tr gi c th c nh lng da trn kt qu so snh thi gian gi n im o v gi tr tham chiu c chn t gi tr tr ca gi u tin (i), gi tr tr nh nht (ii) hoc gi tr tr trung bnh.
Theo qui nh: Bin ng tr c tnh bng hiu ca gi tr o tr ln nht tr i gi tr o tr nh nht.
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Bin thin tr IPDV
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V d v tr v bin thin tr trn mng
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V d v tr v bin thin tr trn mng
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tn tht gi tin IPLR
Tham s ny c tnh bng tng s gi tin b tn tht so vi tng s gi tin pht i.
Gi gi i khng n c ni nhn, hay pha gi khng nhn c gi phn hi trong khong thi gian xc nh.
V phng din o mt gi c th xem nh trng hp c bit ca tr gi vi gi tr tr vt qu mt ngng thi gian xc nh .
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Cc tham s cht lng lp TCP
Tham s v tc
+ Tr thit lp kt ni
+ Thng lng truyn d liu
+ Tr xa kt ni
+ Thng lng kt ni
Tham s v chnh xc v tin cy:
+ T l li thit lp kt ni
+ T l tht bi thit lp kt ni
+ T l mt kt ni sm
+ T l tht bi xa kt ni
Tham s v kh dng
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Cc tham s cht lng lp cao
Tr giao thc lp cao:
+ Tr p ng dch v lp cao (HLSRD)
+ Tr xc thc lp cao (HLAD)
+ Tr truyn d liu lp cao (HLDTD)
+ Tr dch v lp cao (HLSD)
Tham s sn sng ca giao thc lp cao:
+ T l thnh cng thit lp kt ni (CESR)
+ T l thnh cng dch v (SSR)
+ kh dng ca dch v (SA) :
SSR> SSRth
HLSD
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Cc tham s tr
1- Tr truyn ti mng truy nhp2- Tr truyn ti mng li3- Tr x l xc thc4- Tr x l ng dng
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2
3
4
23
V D, TR P NG DCH V (HLSRD)
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Thng lng truyn d liu
Thng lng truyn d liu c biu din bng cch chia tng s byte gi i trong mt pha truyn d liu cho khong thi gian gia gi tin u tin c gi i v gi tin cui cng n. Thng lng truyn d liu hng ln v hng xung c phn bit.
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Yu cu cht lng dch v
wide range of user requirements, depending on application
0%
Packet Loss
Command/ control(eg Telnet, Interactive
games)
Conversationalvoice and video
Voice/videomessaging
Streamingaudio/video
Transactions (eg E-commerce,Web-browsing, E-
mail access)
Messaging, Downloads
(eg FTP,still image)
Fax
Background(eg Usenet)
5%
100 msec 1 sec 10 sec 100 sec
Interactive Responsive Timely Non-critical
Delay
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Phn chia QoS class
QoS Class
Loi ng dng
V dService Class
802.1P DiffServ Codepoint
MPLS EXP
Class 0Routing
ProtocolsRSVP, OSPF, ISIS,
BGPControl 6 CS-6 EXP 6
Class 0 VoIP Voice Telephony
5
EF
EXP 5Class 2
Voice Application Signalling
SIP, H.248, IGMP Signalling EF
Class 2Precision
Time Distribution
IEEE1588v2 Signalling EF
Class 2 VideoVideo on Demand,
Broadcast TV
Broadcast video
4
AF41
EXP4
Class 1Network
ManagementSNMP, SSH OAM AF41
Class 3Enterprise
Data 1
Point-to-Point, Multipoint-to-
Multipoint services
High throughput
data3 AF31 EXP 3
Class 4Enterprise
Data 2
Point-to-Point, Multipoint-to-
Multipoint services
High throughput
data2 AF21 EXP 2
Class 5
Internet Traffic
Business HSI (FTTH)
Standard
1
Default
In-profile
EXP 1
Class 5Residential HSI (DSLAM, FTTB,
FTTC)0
Out-of-profile
EXP 0
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Ch tiu cht lng mng ton trnh trong cung cp dch v
Tham s
QoS Class Tr truyn gi tin mt
chiu
(IPTD)
Bin ng tr
(IPDV)
T l tn tht gi tin
(IPLR)
T l li
gi tin
(IPER)
T l b qua gi tin
(IPDR)
Class 0 100 ms 50 ms 1 103 1 104 -
Class 1 400 ms 50 ms 1 103 1 104 -
Class 2 100 ms U 1 103 1 104 -
Class 3 400 ms U 1 103 1 104 -
Class 4 1 s U 1 103 1 104 -
Class 5 U U U U -
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Pht trin ca cc k thut QoS
29
Cc bin php m bo QoS
Phng nga tc nghn:
o Chp nhn kt ni (Admission control)
o Trafic shaping
Cc k thut m bo QoS.
X l khi c tc nghn, s c: truyn li, gim ti, d phng, nh tuyn li.
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X l QoS trn b nh tuyn
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Qun l hng i RED
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Qun l hng i tch cc
Qun l theo chiu di hng i: RED, WRED,
Qun l hng i theo tc lu lng: BLUE, RAQM, .
Kt hp: REM,....
Thng bo tc nghn ECN
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Lp lch
WRR, WFQ, CB-WFQ,
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Chia ct lu lng
35
M hnh IntServ
RSVP
Tnh ton ti nguyn m bo QoS
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M hnh DiffServ
MPLS, K thut lu lngTE, RSVP-TE
M hnh DiffServ
37
Gi cc chuyn
M hnh lu lng: m hnh Markov, long-rang dependent,
Chp nhn kt ni (AC).
Cc k thut qun l hng i tch cc.
Cc k thut lp lch.
K thut chia ct lu lng.
Giao thc RSVP, RSVP-TE.
K thut lu lng MPLS.
M hnh DiffServ.
Tnh ton ti nguyn: bng thng, b m tha mn cc tham s QoS (loss, delay).
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Bo co chuyn
cng: tn chuyn ; mc tiu, ni dung, kt qu. Np li cho thy sau 2 tun.
Bo co chuyn : 10-20 trang.
Bo co kim tra (10 pht/ sinh vin): Bo co5 pht (slides); Hi kim tra.
nh gi: Ni dung bn bo co, trnh bybo co trn lp, tr li cu hi.
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