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EndEnd--toto--End QoS Provisioning End QoS Provisioning Technologies for B3GTechnologies for B3G
ETRIETRI김김 재재 현현
20042004년년 22월월 2828일일
AjouAjou UniversityUniversity
2
목차목차
End-to-End QoS 정의
Service Traffic 별 QoS 요구사항
End-to-End QoS를 보장하기 위해 필요한 기능
Network QoS 보장 기술 분석
End-to-End QoS 보장기술 및 표준
3GPPITU-T
Case Study3GPP2Home Network
End-to-End QoS Research IssuesSummary
3
EndEnd--toto--End QoS End QoS 정의정의
QoS 정의
ITU-T (International Telecommunications Union-Telecommunication) “The collective effect of service performance which determines the degree of satisfaction of a user of the service.”
IETF (Internet Engineering Task Force)“A set of service requirements to be met by the network while transporting a flow.”
Core NetworkCore NetworkCore Network
AV StreamingVoiceGameFTPWEB, …
Real Time Traffic에QoS 보장 필요
(Bandwidth, Latency, Jitter고려)
4
Service TrafficService Traffic별별 QoS QoS 요구사항요구사항
Traffic의 특성에 따라 QoS 보장을 위해 필요한 요구사항이 다름
Service Payload Rate(Mbps) Latency(ms) Jitter(ms) PER
High Quality Voice 0.064 X 2 streams 10 5 10-3
Video Conference 1.5 X 2 streams 10 ± 5 10-5
HDTV 19.68 90 ±10 10-5
SDTV 3 90 ±10 10-5
High Speed Data 10 >100 >100 0
Medium Speed Data 2 >100 >100 0
Low Speed Data 0.5 >100 >100 0
ReferenceL. Chinitz, “Quality of Service in the Home Networking Model,” Home RF working group, Aug., 2001.
5
EndEnd--toto--End QoSEnd QoS를를 보장하기보장하기 위해위해 필요한필요한 기능기능
중요 QoS 파라미터
BandwidthCapacity, Utilization, Available Bandwidth (ABW)
LossRandom Packet Loss, Bursty Packet Loss
DelayOne-Way Delay, Round -Trip Time (RTT), Delay Jitter
서비스에 따라 필요한 QoS의 기능
Packet classifier, network resource management 지속적으로 트래픽이 발생하는 서비스
Parameterized QoS provision technology : 안정적인 자원 할당
Admission control, shaperPriority QoS provision technology : 서비스 별 전송 순위의 차별화
QoS Policer, Packet Scheduler
6
EndEnd--toto--End QoSEnd QoS를를 보장하기보장하기 위해위해 필요한필요한 기능기능((ConCon’’tt))
Classifier : Selects packets based on portions of packet headerMarker : Marks/Remarks the packet header based on traffic classMeter : Checks compliance to traffic profile and passes result to Marker and Shaper/DropperShaper : Allows for delaying of packets in buffer to enforce compliance with traffic profileDropper : Drops traffic that does not conform with traffic profileCongestion Avoidance : Checks buffer levels and stochastically drops packetsScheduler : Allows for differential queueing and servicing of packets
7
NetworkNetwork에서의에서의 QoS QoS 보장보장 기술기술
ATM Network PVC/ Soft-SVC/SVC
ALL_IP: IntServ and RSVPA per-flow resource reservation based approach to enable end-to-end QoS guaranteeAdmission control, resource reservation, routing, etc.RSVP is the signaling protocol used to implement IntServ resource reservation
ALL_IP: DiffServA scalable provision scheme to provide hop-by-hop differentiated service for aggregated flowsNo per-flow state kept in network elementsNo signaling required IETF DiffServ PHB Scheduling Classes (PSCs)
EF (Expedited Forwarding)AF (Assured Forwarding)CS (Class Selector)DF (Default Forwarding)
8
NetworkNetwork에서의에서의 QoS QoS 보장보장 기술기술
IntServ over DiffServProvide IntServ service to the user on top of a DiffServ core network
Edge-routers process RSVP signaling and map end-to-end QoS requirements to DiffServ service classesBorder routers perform admission controlDiffServ core routers only provide DiffServ per-hop differentiated services
9
NetworkNetwork에서의에서의 QoS QoS 보장보장 기술기술
ALL_IP: Policy-based Network Management (PBNM)Using policies and policy servers to provide QoS services based on the contract between the service provider and the usersThe edge routers consults policy server to perform admission controlThe core routers accept resource configurations from policy server to implement certain QoS service requirements
Policy Policy ServerServer
10
History of 3GPPHistory of 3GPP
Circuit domainGSM Radio
Packet domain
UMTS Radio
HomeHome
11
General Architecture of 3GPP General Architecture of 3GPP
3GPP divided the mobile system in several partsIMS enables IP based services, e.g. telephonyPS domain provides packet bearer services with QoS and mobility support A bearer service contains all aspects to enable the provision ofQoS, i.e. QoS signaling, transport and QoS managementGGSN is anchor for IP address of moving UE
PS DomainPS DomainPS Domain
CS DomainCS DomainCS Domain
UEUE(Use Equipment)(Use Equipment)
RNCRNC
RANRAN(Radio(RadioAccessAccessNetwork)Network)
SSGNSSGN GGSNGGSN
IMSIMS(IP (IP MulitmediaMulitmedia
Subsystem)Subsystem)IMSIMS
12
QoS Architecture in 3GPPQoS Architecture in 3GPP
TE MT RAN CN Iu EDGE NODE
CNGateway
TE
3GPP
End-to-End Service
TE/MT Local Bearer Service
UMTS Bearer Service External BearerServiceUMTS Bearer Service
Radio Access Bearer Service
CN BearerService
BackboneBearer Service
IuBearer Service
Radio BearerService
Physical Radio Bearer Service
Physical Bearer Service
TE: Terminal Equipment, MT: Mobile Terminal, RAN: Radio Access NTE: Terminal Equipment, MT: Mobile Terminal, RAN: Radio Access Network, CN: Core Networketwork, CN: Core Network
Several Bearer Services with clearly defined characteristics and functionality are specified
ReferenceReference3GPP TS 23.1073GPP TS 23.107
IP Bearer only in RelIP Bearer only in Rel--55
IP BS ManIP BS ManIP Policy EnforcIP Policy Enforcand optionally also on RSVP/and optionally also on RSVP/
ager. Uses Diffserv Edge Function, ager. Uses Diffserv Edge Function, ement Point ement Point
IntServ. IntServ.
13
QoS Parameter of 3GPPQoS Parameter of 3GPP
The QoS parameters differ according to the considered link. The following slides provide the QoS parameter for “UMTS BS”and “RAB Service”
Traffic class Conversational class Streaming class Interactive class Background
Example of application Voice Streaming video Web browsing
Background download of emails
Fundamental characteristics
- Preserve time relation (variation) between information entities of the stream - Conversational pattern stringent and low delay
- Preserve time relation (variation) between information entities of the stream
- Request response pattern - Preserve payload content
- Destination is not expecting the data within a certain time- Preserve payload content
ReferenceReference3GPP TS 23.2073GPP TS 23.207
14
QoS Parameter Attributes and RangesQoS Parameter Attributes and Ranges
Different QoS attributes and ranges per traffic classTraffic class Conversational Streaming Interactive Background
Maximum bitrate(kbps) <=16000 <=16000 <=16000 <=16000
Maximum SDU size (octets) <=1500 <=1500 <=1500 <=1500
SDU format information
SDU error ratio 10-2, 7*10-3, 10-3, 10-4, 10-5
10-1, 10-2, 7*10-3, 10-
3, 10-4, 10-5 10-3, 10-4, 10-6 10-3, 10-4, 10-6
Transfer delay (ms) 100 – maximum value
280 – maximum value
Guaranteed bit rate (kbps) <=16000 <=16000
Traffic handling priority 1,2,3
Allocation/Retention priority
1,2,3 1,2,3 1,2,3 1,2,3
Source statistic descriptor Speech/unknown Speech/unknown
ReferenceReference3GPP TS 23.2073GPP TS 23.207SDU : Service Data UnitSDU : Service Data Unit
15
PS Domain PS Domain
Introduction of IMSIntroduction of IMS
Circuit domainGSM Radio
Packet domain
UMTS Radio
HomeHome
IMSIMS
IMSIMSService ControlService ControlSIPSIP
-- IMS : IP Multimedia SubsystemIMS : IP Multimedia Subsystem
16
Details of IMSDetails of IMS
UTRANUTRAN
SGSNSGSN GGSNGGSN
HSSHSSII--CSCFCSCF
PP--CSCFCSCF
SS--CSCFCSCFOtherOtherIP/IMSIP/IMSNetworkNetwork
Serving-CSCF (Call Session Control Function)Performs the Session Control: handles the SIP requests and forwards them to the S-CSCF /external IP network of other end user.The S-CSCF might be specialized for the provisioning of a (set of) service(s).
Interrogating-CSCF“main entrance” of the home network: Selects (with the help of HSS: Home Subscriber Server) the appropriate S-CSCF
Proxy-CSCF“first contact point” of IMS: located in the visited network, selects the I-CSCF of the Home Network of the user. Performs some local analysis (e.g. number translation, QoS policing,..)
SIP signalingSIP signaling
User DataUser Data
17
Overview of Protocol StackOverview of Protocol Stack
L1
RLC
PDCP
MAC
IP v6
SIP
L1
RLC
PDCP
MAC
ATM
UDP/IP
GTP-U
AAL5
Relay
L1
UDP/IP
L2
GTP-U
IPv6
3G-SGSNUTRAN MS Iu-PSUu Gn
3G-GGSN
ATM
UDP/IP
GTP-U
AAL5
L1
UDP/IP
GTP-U
L2
Relay
UDP
L1
L2
UDP
IP
ATM
AAL5
Gi
UDP
IP
P-CSCF
SIP
TransportLayers
Mw I-CSCF S-CSCF
Mw
UDP
TransportLayers
ATM
AAL5
UDP
IP
TransportLayers
IPv6
UDP
IPv6
SIP
TransportLayers
UDP
TransportLayers
IPv6
UDP
Transport Layers
IP v6
UDP
SIP
PS domain transport Backbone transport
IMS SignallingSIP SIP SIP SIP
IPv6 IPv6 IPv6 IPv6
P-CSCF S-CSCF
18
QoS Management Function in the QoS Management Function in the Control PlaneControl Plane
IP BSManager
TranslAdm./Cap.
Control
UMTS BSManager
RadioBS Manager
UTRAph. BS M
UE
Adm./Cap.Control
RABManager
RadioBS Manager
UTRAph. BS M
UTRAN
Adm./Cap.Control
UMTS BSManager
CN EDGE
IP BSManager
Adm./Cap.Control
UMTS BSManager
Gateway
Iu BSManager
Iu NSManager
Subsc.Control
Iu BSManager
Iu NSManager
CN BSManager
BB NSManager
Transl
CN BSManager
BB NSManager
ExtNetw.
ExtServiceControl
localSIP proxy
Policy ControlFunction
P-CSCF
service primitive interfaceprotocol interface
UE : User Equipment, PUE : User Equipment, P--CSCF : ProxyCSCF : Proxy--Call Session Call Function, BS : Bear Service, RAB : Radio AccesCall Session Call Function, BS : Bear Service, RAB : Radio Access Bear, NS : Network Services Bear, NS : Network Service
ReferenceReference3GPP TS 23.2073GPP TS 23.207
19
QoS Management Function in the QoS Management Function in the Control Control Plane(ConPlane(Con’’tt))
Translation FunctionConvert between external service signalling and internal service primitives including the translation of the service attributes
UMTS BS ManagerSignal between each otherVia the translation function with external instance to establish or modify a UMTS bearer serviceInterrogates its associated admission/capability whether the network entity supports the specific requested service and whether the required resources are available
RAB ManagerVerifies with its admission/capability control whether the UTRAN supports the specific requested service and whether the required resources are availableTranslates the RAB service attributes into radio bearer service and IU bearer service attributes and request the radio BS manager and the Iu BS manager to provide bearer services with the required attributes
20
QoS Management Functions in the QoS Management Functions in the User PlaneUser Plane
Class
ResourceManager
UE UTRAN CN EDGE Gateway ExtNetw.
TE
Cond.
UTRAN phys. BS
Lacal BS
Cond.
ResourceManager
Mapper.
ResourceManager
Iu Network Service
Mapper
ResourceManager
ResourceManager
BB Network Service
Class
ResourceManager
Cond.
Mapper
External BS
Data flow with indication of direction
ReferenceReference3GPP TS 23.1073GPP TS 23.107
21
QoS Management Functions in the QoS Management Functions in the User User Plane(ConPlane(Con’’tt))
Classification Function (Class)Assign user data units received from the external bearer serviceor the local bearer service to the appropriate UMTS bearer service according to the QoS requirements of each user data unit
Traffic Conditioner (Cond.)In MT : Provides conformance of the uplink user data traffic with the QoS attributes of the relevant UMTS bearer serviceIn Gateway : Provide conformance of the downlink user data traffic with the QoS attributes of the relevant UMTS bearer service.
Mapping FunctionMarks each data unit with the specific QoS indication related tothe bearer service performing the transfer of the data unit
Resource ManagerDistributed its resources between all bearer services requestingtransfer of data units on these resources
22
ITUITU--T Y.1540 Performance ParametersT Y.1540 Performance ParametersIP Application QoS Performance Parameters
IP Transfer Delay (IPTD)Propagation Delay: function of distanceTransport Delay: function of processing in nodesCodec Delay: signal conversionJitter Buffer Delay: smoothing delay variability
IP Delay Variability (IPDV) (Jitter)
IP Packet Loss Ratio (IPLR)congestion discards, delay variation discardsBursts or random
IP Packet Error Ratio (IPER)
23
ITUITU--T Y.1541T Y.1541 QoS ClassesQoS Classes
Network Performance Y.1541 QoS Classes
Parameter Class 0 Class 1 Class 2 Class 3 Class 4 Class 5
IPTD 100ms 400ms 100ms 400ms 1 s U
IPDV 50ms 50ms U U U U
IPLR 1*10-3 1*10-3 1*10-3 1*10-3 1*10-3 U
IPER 1*10-4 U
VoiceBest Effort
DataSignaling
Interactive Data Streaming Video
Classes resolve scaling issues
Example Service
Mappings
Note that delay variability is the distinguishing difference between Classes 0,1 and 2,3
24
Scope of QoS Signaling Scope of QoS Signaling ReqtsReqts.. in IP in IP NetworkNetwork
TE TEGW . . .
NetworkEnd-End Network (IP Service QoS)
Network NetworkCustomer Installation Customer Installation
User-to-User Connection (Transport and higher QoS)
TE GWTerminal EquipmentGatewayRouter Protocol Stack
LAN LAN
IP Network Cloud
UNI UNI
*NI Network Interface
GW GW GW GW GW
DSTSRC
NNI NNI
Protocol Requirements
25
Control Plane and Data Plane Mechanisms: Control Plane and Data Plane Mechanisms: RelationshipRelationship
EndEndSystemSystem
EndEndSystemSystem
Call/Session ControlCall/Session Control
Packet ForwardingPacket Forwarding
Call/Session Control (with indication of QoS Class)Call/Session Control (with indication of QoS Class)Session IP flowSession IP flowQoS QoS mechanism(e.gmechanism(e.g. RSVP or Diffserv packet marking). RSVP or Diffserv packet marking)Gate ControlGate Control
26
Interworking ITU/3GPPInterworking ITU/3GPP
For end to end service delivery, industry convergence on a single set of QoS Classes to be signaled end to end is desirable
The ITU-T QoS Classes should be globally supported
Currently: ITU-R/3GPP differ
Globally Standardized Interworking betweenWireless (ITU-R/3GPP) and Wireline (ITU-T) networks
27
Case StudyCase Study
28
3GPP23GPP2
29
EndEnd--toto--End QoS Architecture of 3GPP2End QoS Architecture of 3GPP2
MSMS : Mobile Station,: Mobile Station, PDSN/AGWPDSN/AGW : Packet Data Serving Node/ Access Gateway, : Packet Data Serving Node/ Access Gateway, BRBR : Border Router, : Border Router, CNCN : Correspondent Node (mobile station),: Correspondent Node (mobile station), HAHA : Home Agent, : Home Agent,
ReferenceReference3GPP2 S.R00793GPP2 S.R0079--00
30
EndEnd--toto--End QoS Reference ModelEnd QoS Reference Model
HAAAHAAA : Home AAA, : Home AAA, VDBVDB: Visited Data Base, : Visited Data Base, HDBHDB : Home Data Base, : Home Data Base, PP--CSCFCSCF : Proxy: Proxy--Call Session Call Session Control Function, Control Function, SS--CSCFCSCF : Serving: Serving--Call Session Control Function , Call Session Control Function , PDFPDF : Policy Decision Function: Policy Decision FunctionSLASLA : Service Level Agreement: Service Level Agreement
An example of the End-to-End QoS architecture
ReferenceReference3GPP2 S.R00793GPP2 S.R0079--00
31
Reference Architecture (3GReference Architecture (3G--EVDEVDOO))
Can model reference connections including applications and data center
32
Protocol Stack for 3GProtocol Stack for 3G--1X Data 1X Data (ATM)(ATM)
AT 3G-1XCell
PC 3G-1X MSC Host
10 Base TRS-232
Cable
3com
3G3G--1x1xBTSBTS
Ethernet
MAC
IP
TCP/UDP
PPP
Ethernet
MAC
Airlink
MAC
RLP
Airlink
MAC
T1
ATM
PP/T1
ATM
T1
FR
IPRMI
ServersServers
3G3G--1x1xMSCMSC
PCF
PCFPCF
T1
FR
Phys
GRE
L2 L2
Phys
IP
TCP/UDP
PDSNPDSN
Air
AAL2
T1
FR
T1
ATM/AAL5
OC3
Airlink
ATM
T1
ATM
ATM SwitchATM Switch
PSAX
AAL2
T1
RLP
Application Application
Phys
L2 L2
Phys
IP
GREPPP
IP
IP IP -- Internet ProtocolInternet Protocol, , TCP TCP -- Transmission Control ProtocolTransmission Control Protocol, RLP, RLP-- Radio Link ProtocolRadio Link ProtocolUDPUDP-- User Datagram ProtocolUser Datagram Protocol, , PPP PPP -- PointPoint--toto--Point ProtocolPoint Protocol, , FR FR –– Frame RelayFrame Relay
33
Protocol Stack for 3G EVDO Protocol Stack for 3G EVDO (HDLC)(HDLC)
AT 1xEV-DOCell
PC RAN Router 1xEV-DO FMS Host
ServersServers
1xEV1xEV--DODOControllerController
PCFPCFPDSNPDSN
1xEV1xEV--DODOBTSBTS
RouterRouter
PCF PDSN
Ethernet
MAC
IP
TCP/UDP
PPP
Ethernet
MAC
Airlink
MAC
RLP
Airlink
MAC
T1/E1
HDLC
IP
TCP/ UDP
RMI
T1/E1
HDLC
Ethernet
MAC
IP
Ethernet
MAC
T1/E1
L2
IP
TCP/ UDP
IP
GRE
RMI
RLP
T1/E1
L2 L2
Phys
IP
GRE
PPP
IP
L2
Phys
IP
TCP/UDP
Application Application
10 Base T
Cable Backhaul
R-P (A10/A11) IP NetworkRouter
GRE GRE -- Generic Routing Encapsulation (protocol)Generic Routing Encapsulation (protocol), , RMI RMI -- Remote Method InvocationRemote Method Invocation, , IP IP -- Internet Protocol Internet Protocol TCP TCP -- Transmission Control ProtocolTransmission Control Protocol UDPUDP-- User Datagram ProtocolUser Datagram Protocol, , PPP PPP -- PointPoint--toto--Point ProtocolPoint ProtocolHDLC HDLC –– High Level Data Link ControlHigh Level Data Link Control
34
3G+ Wireless Technology Evolution3G+ Wireless Technology Evolution ::Reference Architecture for Voice TrafficReference Architecture for Voice Traffic
IP
64k PCM/32K ADPCM
PCM
BTS
ATMAAL2
ATM
Packet Pipes ATM
PCM/ Channelized T1
PSAXPSAX
MSCPSTN
Media Gateway
PSAXPSAX
MSC
BTS
ATMAAL2
ATM
Packet Pipes
PCM
Media Gateway
IP Router
64k PCM/32K ADPCM100BT
Ethernet
GX550 GX550
1
2 3
1
1
2.5G2.5G
Voice call FlowTDM
2
3
ATM :PCM 64 kbps
ATM :ADPCM 32 kbps
Tandem Tandem
4
4 IP :G.726 32 kbps
100BTEthernet
TMX880 TMX880
IP Router
RNCRNC5
5
3G3G
3G+3G+
IP :Vocoder bypass
35
3G+ Wireless Technology Evolution3G+ Wireless Technology Evolution ::EndEnd--toto--end voice packet delayend voice packet delay
0
50
100
150
200
250
mse
c
TDM tandemG.711 (64kbps)
ATM BackboneG.711 (64kbps)
AAL1
ATM BackboneG.726 (32kbps)
AAL2
IP BackboneG.726 (32kbps)
IP backboneVocoder Bypass
Technologies
Uplink Avg. Delay BackBone Avg. Delay Downlink Avg. Delay
No significant difference between ATM and IP backbone Vocoder bypass : delay decrease and better voice quality due to no trans-vocoder
E2E One Way Delay (ms)
64 kbps (G.711)
32 kbps(G.726) 16kbps(G.728)
0 94 87 50 93 86 100 92 85 150 90 83 200 87 80 250 80 73 300 74 67 350 68 61 400 63 56 450 59 52
450
9 0 - 1 0 0 B e s t q u a l i t y ; u s e rs v e r y s a t is f ie d
8 0 -9 0 H ig h q u a li t y ; u s e rs s a t is f ie d
7 0 -8 0 M e d iu m q u a li t y ; s o m e u s e r s d is s a t is f ie d
6 0 -7 0 L o w q u a li t y ; m a n y u s e r s d is s a t is f ie d
5 0 -6 0 P o o r q u a li t y ; n e a r ly a l l u s e r s d is s a t is f ie d
L e s s th a n 5 0
U n a c c e p t a b le q u a l i t y
Source: IEEE Communications Magazine, July 1999
Voice Quality Scores (R value)
Uplink : MT – BTS – MSC/RNCBackbone : MG – Switch/Router – MGDownlink : MSC/RNC - BTS - MT
36
3G+ Wireless Technology Evolution3G+ Wireless Technology Evolution : : Voice : Background load vs. JitterVoice : Background load vs. Jitter
Scenarios IP backbone voice scenarioWeb browsing background traffic in links Web data rate fixed to uplink 64 Kbps and downlink 153 KbpsNo QoS mechanism implemented
QoS mechanism should be support in the backhaul and backbone(end-to-end).
Back-groundTraffic Load
Avg. End-to-end packet delay (msec)
P( x < X) = 0.95Avg. pkt. delay(msec)
Avg. Jitter
(msec)
0% 219 219.8 0.0043
40% 233 261.8 1.99
10% 221 222.7 0.426
30% 229 246.5 1.51
70% 266 360.4 6.4
80% 301 425.9 12.4
0
50
100
150
200
250
300
350
400
450
mse
c
0% 10% 30% 40% 70% 80%
Backgorund traffic
Avg. End-toend delay 95% delay Avg. Jitter
37
3G+ Wireless Technology Evolution3G+ Wireless Technology Evolution ::Backbone Network Evolution (ATM vs. IP)Backbone Network Evolution (ATM vs. IP)
Web page response time for the different backboneIP backbone reduced little end-to-end delay due to lower header overhead and SAR delay compared to ATM backbone (5.2%, 7.7 %)Other Performance Issues : TCP Window sizes (UNIX vs. MS Server), HTTP version, etc.
9.69 9.1
8.3
0
2
4
6
8
10
12
mea
n pa
ge re
spon
se ti
me
(mse
c)
ATM IP
Backbone transport technologies
EVDO HDLC(T1) Ethernet (100BT)
38
3G+ Wireless Technology Evolution3G+ Wireless Technology Evolution : : 3G3G--11XX, EVDO vs. EVDV, EVDO vs. EVDV
Web page response time for the technologies phaseDelay is reduced 46% from 3G-1X trial to EVDV technology in 10% BLERImprovement not proportional to difference in air interface speedsHigher speed air interface is expected to see higher BLER - improvement may not be good as 46%.
3.5 3.42.6 2.5
9.18.3
7
5
15.1
11.5
9.38.1
0
2
4
6
8
10
12
14
16
page
resp
onse
tim
e (s
ec)
No FER 4% FER 10% FER
FER
3G-1X RTT (F:153 Kbps, R:64 Kbps)3G-1X (F:153 Kbps, R:153 Kbps)EV-DO (F:2.4 Mbps, R:153Kbps)EV-DV (F:2.4 Mbps, R:2Mbps)
39
Home NetworkHome Network
40
홈홈 네트워크네트워크 정의정의 및및 QoSQoS보장보장 필요성필요성
VoD 서비스IPTV 서비스양방향멀티미디어서비스
위성디지털방송or
케이블디지털방송or
지상파디지털방송
인터넷망
FTTH (155Mbps 이상)FTTO (155Mbps 이상)
Ethernet (100Mbps)
WLAN
ResidentialGateway
UWB Network(100 Mbps)
UWB
WLAN Network(최대 54Mbps)
IEEE1394 Network(400 Mbps ~ 1.6GHz)
IEEE1394
PacketScheduling
QoS mapping
병목현상병목현상발생가능발생가능
Ethernet(100Mbps)
QoS mapping
PacketScheduling
홈 네트워크 정의
홈 네트워크란 다양한 유․무선망 접속기술을 이용하여 댁내의 정보가전제품에서 백색가전제품에 이르기까지 모든 전자제품들을 하나의 망으로 형성하여 사용자의 편의를 극대화하는기술이다.
홈 네트워크에서의 QoS 보장 필요성
홈 네트워크에서 발생되는 트래픽의 종류와 접속기술이 다양하므로 고품질의 실시간멀티미디어 서비스를 제공하기 위해서는 residential gateway에 다양한 네트워크 환경을고려한 QoS 보장 기술이 필요
41
Ethernet QoS Ethernet QoS 보장기술보장기술 분석분석
802.1q에 의해 QoS 정의
Priority 기반의 QoS 메커니즘
자원 예약과정 없이 단순히 트래픽에 따라 분류하여 전송
상위 클래스의 트래픽이 큐에 있으면 하위 클래스의 패킷은 전송할 수 없음
Call admission control 프로토콜의 부재로 망이 혼잡해질 위험성이 큼
하나의 응용 서비스 트래픽이 사용할 수 있는 자원의 한계를 정하고 있지 않음
Priority Group Service type Priority 지원 서비스
Highest 망 관리와 제어 트래픽에 관련 111
110
101 Game, telephony, videophones, Web conferencing
110 Movies, channel changing, security, camera monitoring
Game, telephony, videophones, Web conferencing
Movies, channel changing, security, camera monitoring
010
001
011
000
RIP,OSPF table의 갱신에 사용
Stream setup and control
2nd highest Parameterized services
Stream setup and control
3rd highest Prioritized services
4th highest Best-effort로 전송 Web surfing, printing
ReferenceReferenceN.N, QoS: Assigning Priority in IEEE 802N.N, QoS: Assigning Priority in IEEE 802--style Networks, 16.8.1998, [style Networks, 16.8.1998, [defereddefered 15.4.1999] 15.4.1999]
ReferenceReferenceG.stoneG.stone: QoS a concern in linking 1394, Ethernet, 2003: QoS a concern in linking 1394, Ethernet, 2003
42
IEEE1394 QoS IEEE1394 QoS 보장기술보장기술 분석분석
Ch B Ch C Ch D Ch ECycle
StartCh B Ch C Ch D
Cycle
StartCh B
Cycle
Start
Packet
B
Nominal cycle period = 125 us Nominal cycle period = 125 us
DelayCycle n Cycle n+1
Cycle Sync
AC
K
Delay
Packet
B
AC
KCh D
: Isochronous Transactions : Asynchronous Transactions
Subaction (long) Gaps Subaction (long) Gaps Subaction (long) Gaps
Isochronous (short) gaps Isochronous (short) gaps
One byte time slots
Cycle SyncCycle Sync
Isochronous modeIRM (Isochronous Resource Manager), BM (Bus Manager)에 의해 필요
Bandwidth와 channel을 할당 받음
Asynchronous modeCompare and swap method 사용
패킷 전송을 성공한 노드는 일정시간 동안 새로운 채널을 요구할 수 없음
Physical ID가 낮거나 root 노드에 가까우면 채널을 점유할 기회가 높아짐
서비스에 따라 차별화된 QoS를 제공 못함
: Cycle starts Packets
43
IEEE 802.11e QoS IEEE 802.11e QoS 보장기술보장기술 분석분석AC CWmin CWmax
AC_VO (CWmin+1)/4-1 (CWmin+1)/2-1
AC_VI (CWmin+1)/2-1 CWmin
AC_BE CWmin CWmax
AC_BK CWmin CWmax
With 802.11aaSlotTime: 9usSIFS: 16usPIFS: 25usDIFS: 34usAIFS: >=34 us
ACK RTS
CTS
SIFS SIFS
PIFS
AIFS[AC]=DIFS
SIFS
AIFS[AC]
AIFS[AC]
high priority AC
medium priority AC
low priority AC backoff
backoff
defer accessContention Windows(counted in slots, 9us
count down as long as medium is idle,Back off when medium gets bust again
CW=rand[1,CWi+1]
1 max
1
[ ] min[{( [ ] 1) [ ]} 1, ][0, [ ]]
i i
i
CW AC CW AC PF AC CWBackoff rand CW AC aSlotTime
+
+
= + × −= ×
EDCA 서비스의 종류에 따라 priority 기반의 차별화된QoS를 제공
AIFS, Cw_min, Cw_max, TxOP, PF등의factor를 사용
4개의 AC (Access category)를 정의
EDCA ParametersContention Window ParametersMax. TXOP duration (TXOP Limit)
TxOPSTA가 채널을 할당 받았을 때 연속하여 점유할수 있는 시간
44
IEEE 802.11e QoS IEEE 802.11e QoS 보장기술보장기술 분석분석HCCA
예약기반의 QoS를 제공
TSPEC(전송률, 패킷의 크기, 지연, 서비스 간격을 명시) 을 이용한 자원 협상
DLP를 사용하여 HC의 도움 없이 STA간에 데이터를 전송
TBTT이전에 데이터의 전송을 완료할 수 없으면 다음 superframe에서 재시도
서비스에 따라 TxOP의 한계값이 결정되어 있음
CFP뿐만 아니라 CP에서도 전송이 가능함
CFP(polling through HCF) CP (listen before talk and polling through HCF)
TXOP TXOP TXOP TXOPTBTT
QoS CF-Poll QoS CF-PollCF-endBeacon
Transmitted
by (Q)STAs
Transmitted
by HC
TBTTTime
RTS/CTSRTS/CTSFragmented Fragmented DATA/ACKDATA/ACK(polled by HC)(polled by HC)
RTS/CTS/DATA/ACKRTS/CTS/DATA/ACK(after (after DIFS+backoffDIFS+backoff))
RTS/CTSRTS/CTSFragmented Fragmented DATA/ACKDATA/ACK(polled by HC)(polled by HC)
HCCA : HCF Controlled Channel Access, TSPEC : Traffic Specification, DLP : Direct Link ProtocolHC : Hybrid Coordinator로 AP와 동일, EDCA: Enhanced Distributed Channel AccessCFP : Contention Free Period, CP : Contention Period, TxOP : Transmission Opportunity PF : Persistent Factor
45
이종이종 접속기술접속기술 간간 QoS QoS 보장보장 문제점문제점
접속기술 QoS 보장 문 제 점
Ethernet→1394
Streaming 트래픽은 asynchronous mode로 전송할 수 밖에 없음
패킷 크기의 차이 때문에 패킷이 손실될 경우 전체 패킷을 다시 전송해야만 함
Ethernet←1394
전송속도의 차이에 의해 bottle neck이 생길 수 있음
isochronous mode로 전송된 서비스 트래픽을 ethernet으로 전송할 경우 Best Effort로만 전송 가능
Ethernet←802.11
HCCA를 사용하여 전송된 트래픽을 외부 access 망으로 사용하는 Ethernet으로전송할 경우 트래픽 패턴이 손상될 수 있음
1394←802.11
EDCA로 전송된 트래픽은 서비스 클래스에 상관없이 Asynchronous mode로만전송 가능
패킷의 크기가 달라 별도의 큐가 필요
Ethernet→802.11
저속의 단말로 인한 전체 처리율의 저하 현상 (IEEE 802.11 Performance Anomaly)HDTV급의 A/V 트래픽을 하나 이상 지원하기가 어려움
1394→802.11
IEEE1394에서 HDTV와 같은 대용량 A/V streaming 트래픽이 발생할 경우WLAN의 채널 자원이 고갈 가능
46
이종이종 접속기술접속기술 간간 QoS QoS 보장을보장을 위한위한 해결방안해결방안
QoS 파라미터 mappingClass 1
주기적으로 트래픽을 발생
Jitter와 latency에 민감
일정 수준의 에러는 보상할 수 있음
Class 2불규칙적으로 발생하며 트래픽의 크기가 작음
Class 3비교적 낮은 latency와 비교적 높은 처리량을 요구
채널에러에 민감
Class 4트래픽이 burst하게 발생하며 많은 대역폭을 요구
Priority Type Service Type IEEE 1394 IEEE 802.11e
(HCCA사용)IEEE 802.11e
(HCCA사용 안 함) IEEE 802.1p Example
EDCA(AC_VI, AC_VO)
Audio/ Video streamingA/V conferencing
Home automation controlStream setup & control message
Web servicesNetworked home games
E-mail, FTPPeriodic reports
EDCA(AC_BE)
EDCA(AC_BE)
EDCA(AC_BK)
Class 1 Real time streaming isochronous HCCA 7,6,5,4
Class 2 Real time block traffic asynchronous EDCA
(AC_VI, AC_VO) 3
Class 3 Interactive services asynchronous EDCA
(AC_BE) 0
Class 4 Best effort services asynchronous EDCA
(AC_BK) 1,2
47
이종이종 접속기술접속기술 간간 QoS QoS 보장을보장을 위한위한 해결방안해결방안
IEEE 1394 IEEE 802.11 ethernet
Classifier CAC
Class 1 Class 2 Class 3 Class 4EDF SchedulerReservation
Control signal (to CAC)Control signal (from CAC)Data channel
IP layerIP layer에서에서 분류기분류기(Classifier)(Classifier)로로 분류분류Ethernet과 IEEE 802.11은 MAC SDU에 트래픽클래스를 나타내는 필드가 존재IEEE 1394는 Asynchronous mode로 전송할 경우트래픽 클래스는 알 수 없음
Class 1 : Reservation Class 1 : Reservation 방식의방식의 사용사용WLAN
TSPEC에 따라 협상하여 HCCA로 전송IEEE 1394
BM에게 request를 전송하여 필요 자원을 협상Isochronous mode로 채널을 할당
EthernetPriority방식으로 전송할 수밖에 없음
CAC (Connection Admission Control)로 차단Class 1이 자원의 일정량 이상 점유할 경우서비스가 요구하는 QoS를 만족할 수 없을 경우
Class 2,3,4 : Priority Class 2,3,4 : Priority 방식을방식을 사용사용EDF를 이용하여 결정한 deadline의 순서로 전송을시도
Deadline :( ) ( , )( ) ( , )
( ) ( )total reservation
W i J i jD i a i jR j R j
= +−
i : number of class, j : number of superframe, W : weighting factor, J : packet length measured in number of bits Rtot : total bandwidth, Rreservation : reserved bandwidth a: packet arrival time
EDF : Earliest Dead Line
48
Home Gate QoS Guaranteed TechnologyHome Gate QoS Guaranteed Technology
HomePNA IEEE 1394 Ethernet WLAN
UWBWDM ZigbeeDOCSISxDSL
Generic Middware
ClassifierQueue
managerBridge
managerBandwidthmanager
UPnP Jini HAVi Echonet IPHN
Conversation Streaming Interactive Background
Linux Solaris Windows CE
HomePNA
PHYMAC
Middleware
Application
Real-time OS
QoSsupport
QoSsupport
49
SummarySummary
50
네트워크에서의네트워크에서의 QoS QoS 발전단계발전단계
2005~20062005~2006멀티미디어멀티미디어 서비스서비스 중심중심
2007~20082007~2008통합서비스통합서비스 중심중심
2009~20102009~2010지능형지능형 통합서비스통합서비스 중심중심
방송과 인터넷의 융합
개별 Access Tech.의 공존
Access Tech.로융합
단일화된 네트워크통합된 네트워크
하나의 Access Tech.로 단일화
정책(Policy) 기반의동적 QoS
예약(Reservation) 기반의 동적 QoS
Individual Access Tech.• 802.1p, DiffServ• priority 기반의Queuing/Scheduling
Per Hop Behavior
• On Demand Bandwidth & On Demand QoS
• Dynamic SLA Support
Per Flow Behavior
• Multimedia Session QoS
• SIP Aware QoS
SLA : Service Level Agreement, SIP: Session Initiation Protocol
우선권(Priority) 기반의QoS
네트워크네트워크
개별기술개별기술
QoSQoS
서비스서비스
QoS 기술
51
EndEnd--toto--End QoS Research IssuesEnd QoS Research Issues
IP/MPLSIP/MPLSIP/MPLSRNC PDSNRouterRouter
Radio AccessRadio AccessRadio AccessRadio Access CoreCore BackboneBackbone
ContentContentProviderProvider
NetworkNetworkProviderProvider
ServiceServiceProviderProvider
•• Application QoS DefinitionApplication QoS Definition•• Application QoS requirementApplication QoS requirement•• QoS recovery mechanismQoS recovery mechanism
•• Customer SLA Customer SLA •• QoS Policy QoS Policy •• SLA mapping to Net. QoSSLA mapping to Net. QoS
•• Wireless QoS Policy Wireless QoS Policy Map to Map to WirelineWireline
•• Managed NetworkManaged Network
•• EE--tt--E QoS SignalingE QoS Signaling•• QoS MAC/PHYQoS MAC/PHY•• Cross layer QoS MappingCross layer QoS Mapping
•• QoS Res. QoS Res. MgmMgm. . •• Call Adm. Cont.Call Adm. Cont.•• QoS SchedulingQoS Scheduling•• QoS TransportQoS Transport
•• QoS Mapping QoS Mapping
52
ConclusionConclusion
현재 3GPP,ITU-T에서 End-to-End QoS 보장에 관한 연구가 활발히진행 중
End-to-End QoS 보장 기술은 DiffServ에서 signaling procedure를가미한 IntServ 방식의 혼합 방식으로 발전
3GPP : SIP을 이용한 IMSITU : Signaling procedure를 이용한 IP based Network
Network을 통하여 End-to-End QoS를 보장하기 위해서는 다양한QoS 보장 기술들의 연동이 필요
전체 Network는 다양한 Access 기술들이 Core Network에 연결된Hybrid Network임
향후 Network은 단일화될 가능성이 높으므로 다양한 통신 기술들의연동필요
궁극적인 목표인 단일형 End-to-End QoS 보장 기술을 위하여 기반기술인 QoS Parameter Mapping과 QoS Manager를 개발하고, 향후Network aware QoS 보장 기술을 개발 필요
53
ReferenceReference
3GPP 3GPP TS 23.002: “Network Architecture”, 20023GPP TS 22.105: “Services and Service Capabilities”, 20033GPP TS 23.060: “General Packet Radio Service (GPRS)”, 20023GPP TS 23.107: “Quality of Service (QoS) concept and architecture”, 20023GPP TS 23.207: “End-to-end Quality of Service (QoS) concept and architecture, 2004
3GPP2S.R0079-0: “Support for End-to-End QoS, stage 1 Requirements”,2004
“이종 홈 네트워크에서 QoS보장에 관한 연구” 발표자료, Jan. 18, 2005“3G+ Wireless QoS Performance Simulator” 발표자료, Feb. 26, 2004‘http://www.itu.int/ITU-T/worksem/qos/program.html’