A Framework For IntServ Operation Over Diffserv Network

A Framework For IntServ Operation Over Diffserv Network 2000. 11. 네트워크연구실 오승훈

contents • Introduction • Benefits of using IntServ with DiffServ • Frame work • Detailed Ex’s of the operation of IntServ over DiffServ region • Implications of the framework of Diffserv Network region • Multicast

1. Introduction • Intserv • End-to-end QoS , micro flow 별 차등화 서비스. • Services : Controlled loaded , Guaranteed . • Explicit setup mechanism.(ex, rsvp..) • RSVP • service에 알맞은 intserv parameter를 전달 • 단점. • Scalability : per-flow state, per-flow processing • # of RSVP capable host and application is limited.

1. Introduction (cont’) • Diffserv • Class 별 차등화 서비스.(aggregation) • PHB 에 따른 처리.(not end-to-end) • 장점 : scalability, No need for per-flow state and per-flow pressing. •  Intserv (with RSVP) 와 DiffServ 가 상호 보안

1. Introduction (cont’) • Components of Interserv, rsvp and Diffserv • Rsvp signaling : 자원 요청 정보 전달. • Admission control : 수락여부. • MF traffic control : individual flow 별 처리를 위한. • Aggregate traffic control : DHCP 값 기반 class 별 처리 • Aggregate RSVP : rsvp 의 확장, flow의 묶음에 자원 예약. • Per-flow RSVP : conventional usage of RSVP • RSVP/IntServ : the prevailing model of RSVP usage. • Diffserv Region : diffserv를 지원하는 연속적인 라우터의 집합 • NonDiffserv Region : outside of the diffserv region.  목적: for the delivery of e2e QoS for appli. , define the feature of diffserv region ( the type of classification and traffic control.)

1. Introduction (cont’) • The framework • ‘e2e, quantitative QoS’ by applying the intserv over diffserv. • Diffserv “PHB” + Policing <=-=>intserv service. (matching) •  seamless interoperation •  diffserv 망에서도 intserv를 할 수 있다.

2. Benefits of using IntServ with DiffServ • Resource Based admission control • Policy Based admission control • Assistance in Traffic Identification/Classification

2. I Resource Based admission control • Explicit admission Ctrl • Network resource optimally used. • 비교) Diffserv • Providing only aggregate traffic control with no signaling • Admission ctrl : static way. • ex> EF –dscp  50M available • 10 개의 ip-telephony service 요청 (각각 10M 로 가정) • In Diffserv • 10 ip-telephony session open. • But, half of them to be discard  bad quality! • In Explicit admission Ctrl • Network 에 50M 모두 사용 중  call rejection •  upstream element : corresponding action!(refraining, requesting, alternate path!)

2. II Policy Based admission control • In network region where RSVP is used • Intercept the resource request • Identify user, application Against polices (per-user, per-application polices) • Decide if or not to admit a resource request. • In Diffserv region without RSVP signaling. • Policy applied based on the Diffserv customer network , not on the user/application.

2.III Assistance in Traffic Identification/Classification • Within Diffserv network. • Host marking • Host OS mark DSCP -> make decision. • Must be better-equipped than network. • If Ipsec used, host = the only one to make a meaningful determination. • Network 에서 DSCP 값의 의미를 알아야 한다. • “이 자원 요청에 을 만족하는 DSCP 값은 얼마인가?” • Configuration • Setting ( management burden) • Query by RSVP to get DSCPs

2.III Assistance in TrafficIdentification/Classification(cont’) • Router marking • MF classification criteria configured in router • Dynamically by request from the host OS • Statically via Manual configuration or Automated scripts • Based on application or user generating the traffic. • Difficulties by • DHCP에 의한 사용자의 IP 주소 변화 • 다수 사용자들의 IP 공유 • Applic. Transient port 사용 • Alternative way • Host Signals classification criteria to the router -> update MF classification criteria.

3. Frame work • Two specific realization of the framework • 1. Diffserv내의 자원이 정적으로 제공되고 DS망에 rsvp 을 지원하는 라우터가 없음 • 2. Diffserv내의 자원이 동적으로 제공되고 DS망의 몇몇은 rsvp signaling에 참여. • Reference Network • Service Mapping • Resource management in Diffserv

3.I Reference Network • The major components of the reference network • Hosts • e2e RSVP signaling : between Tx and Rx • Edge Router : ER1, ER2 해당. • Diffserv region이 RSVP를 인식하지 못하는 경우 • ER  admission control agent • Diffserv region이 RSVP를 인식하는 경우 Diffserv region Non-diffserv Region Non-diffserv Region BR2 ER2 ER1 BR1 Rx Tx

3.II Service Mapping • 1. 요청된 서비스 <=-=> 적당한 PHB 선택. • Need to communicate the choice of DSCP to network element. : two schemes! • 2. Performing appropriate policing at the edges of the Diffserv region • 3. Exporting intserv parameter from the Diffserv region • 4. diffserv의 자원을 고려해서 the intserv request에 대해 수락제어(Admission control)

3.II Service Mapping(cont’) • Default mapping • Draft-ietf-issll-ds-map-00.txt “integrated Service Mapping for Differentiated Services Networks” • Network Driven Mapping • Upstream 에서 marking이 발생한 경우 • Mapping 정보 전달 필요 -> RSVP 이용

3.II Service Mapping(cont’) • Misbehaving microflow within the aggregate problem. • Per microflow policing at the edge routers • Per microflow policing at the border routers management burden! • Relying on upstream shaping and policing.

3.III Resource management in Diffserv • Various options for management of resource • 1.statically provisioned resource • 2.resource dynamically provisioned by RSVP • 3. Resource dynamically provisioned by other means(ex. Bandwidth broker)

4. Detailed Ex’s of the operation of IntServ over DiffServ region • 1. Statically provisioned Diffserv network region( rsvp unaware) • Negotiate a static contract (SLS) – transmit capacity 를 제공하고자 • Could be complex profile (“burst size , peak rate, time of day….”)

4.1 Statically provisioned Diffserv network region • Sequence of the event ( for e2e QoS) • Host TX generate an RSVP Path msg. • 응용프로그램의 요청 • Path msg(message) host RX로 전송, TX 가 붙어 있는 네트워크 영역에서 RSVP/Intserv 처리 한다. • ER1에서 Path msg 표준적인 RSVP 처리. Path state install or update. Path msg Diffserv 영역으로 전송. • Diffserv 영역에선 Path msg 무시 단지 전달 ER2까지. ER2에서 표준적인 RSVP 처리 • Path msg RX에 도착, RX RESV msg생성 • Diffserv 영역으로 전달 (may be rejected for insufficient resourse) • ER2에서 표준적인 처리 • Diffserv 통과, ER1 에서 RESV msg가 admission control를 trigger 시킨다. (rsvp/intserv의 자원 요청과 diffserv 의 available한 자원을 비교한다.) • ER1 에서 통과되면 , TX 까지의 upstream 까지 전달. • TX 도착 , TX에서 QoS process 가 RESV msg 분석. : • 수락여부 ,적절한 DSCP 값 • TX에서는 보내고자 하는 Packet의 DSCP 를 마킹해서 전송.

4.2 RSVP-aware diffserv network region • BR1 와 diffserv 내의 다른 라우터가 rsvp 를 지원. • Classify and schedule traffic in aggregate , based on DSCP, not on the per-flow classification. • Admission control agent is part of the diffserv network. • 가용한 capacity의 변화가 intserv router에게 전달 될 수 있다. • Diffserv 내의 자원을 효율성 향상, • 구현 방법 • Aggregated RSVP , Per-flow RSVP , Bandwidth-broker

4.2 RSVP-aware diffserv network region(cont’) • Aggregate or Tunneled RSVP • Extending RSVP for aggregation of flows between edges of a network. • Border router <-> core router within diffserv or other Border router between diffservs • 장점 : • offers dynamic , topology aware admission control to the diffserv network

4.2 RSVP-aware diffserv network region(cont’) • Per-flow RSVP • Router in diffserv network respond to the standard per-flow RSVP signaling • 단점 The demand on RSVP signaling is high • Granularity of deployment of RSVP Aware router • # of rsvp-capable routers in the core : by administrator. • 효율성 증가 but overhead 또한 증가. • Aggregate RSVP 는 약간의 효율성 포기와 함께 overhead 를 제한

5. Implications of the framework of Diffserv Network region • Requirements from diffserv network region • Standard RSVP between border. • To invoke these services by use of standard PHB • Must provide admission control to customers. • Must be able to pass RSVP msg

Implications of the framework of Diffserv Network region(cont’) • Protection of intserv Traffic from Traffic • A. e2e Intserv traffic • Associated with quantitative QoS applic. • Requires a specific quantity of resources with a high degree of assurance. • B. Non-Intserv traffic • Intserv service 를 사용하지 않는 traffic • To quantify its requirements , through the use of static provisioning and SLSs at the edge. • Associated with applic that require better-than-best effort service • C. All other (best-effort) traffic  Must be isolated ,by appropriate configuration of policers and classifier at ingress, and by appropriate provisioning to protect intserv traffic = different DSCP used!

A Framework For IntServ Operation Over Diffserv Network