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Ray Hunt Computer Communications 25 (2002) 100-108 Reporter: 李儀訢、黃柏維、王皓正

A review of quality of service mechanisms in IP-based network─integrated and differentiated services,multi-layer switching,MPLS and traffic engineering. Ray Hunt Computer Communications 25 (2002) 100-108 Reporter: 李儀訢、黃柏維、王皓正. Outline : . Introduction Integrated services/RSVP

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Ray Hunt Computer Communications 25 (2002) 100-108 Reporter: 李儀訢、黃柏維、王皓正

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  1. A review of quality of service mechanisms in IP-based network─integrated and differentiated services,multi-layer switching,MPLS and traffic engineering Ray Hunt Computer Communications 25 (2002) 100-108 Reporter:李儀訢、黃柏維、王皓正

  2. Outline: • Introduction • Integrated services/RSVP • Differentiated services • Multi-layer switching • Traffic engineering • Conclusions

  3. Introduction • ISPs are the challenge of offering improved quality of service to their customer. • NO longer is best effort delivery with no service guarantee acceptable for many applications. • IP-based networks only provide Best Effort Service , which implies that there is no guarantee as to delay margins or actual delivery times. • The IETF has proposed many service models and mechanisms to meet the demand for QoS. • Include:IntServ/RSVP , DiffServ , MPLS , and Traffic engineering.

  4. Integrated services/RSVP • The Integrated Services/RSVP (IntServ) model comprises three classes of service: • Best effort─ for time delay independent applications • Guaranteed─ for applications requiring fixed delay • Predictive─ for applications requiring probabilistic delays

  5. Integrated services/RSVP (cont.)

  6. Differentiated services • DiffServ has been available in IPv4 by way of the type of service (TOS). • DS field include: core router , edge router , bandwidth broker • Service currently being defined include: • Assure service ─ for applications requiring better reliability than best effort service. • Premium service ─ for applications requiring low delay and low jitter. • DiffServ provides a very different service offering than IntServ which can be seen from Table1.

  7. Differentiated services (cont.)

  8. Differentiated services (cont.) • Service and resource allocation using band width management • There are four main differences: • IT is the sender that request resources not the receiver • A request can be rejected • A BM can aggregate multiple requests and make a single request to the next BM • Each domain behaves like a single node represented by the BM.ISP core routers are not involved in this process.

  9. Differentiated services (cont.)

  10. Multi-layer switching • Multi-layer switchingare characterised by two components: • Control and forwarding • Label swapping

  11. Control and forwarding

  12. Label swapping

  13. Multi-layer switching (cont.) • Multi-protocol label switching (MPLS) • The motivation for MPLS is to use a fixed-length label to decide upon packet handling. • IT is the latest step in the evolution of multi-layer switching for IP-based network. • Comprise: • Ingress LSR─ Push Label • Core LSR─ Label Swap • Egress LSR─ Pop Label

  14. Multi-protocol label switching (MPLS)

  15. Traffic engineering • The traffic engineering is the process of controlling traffic flow through the network. • Architectural issues of traffic engineering

  16. Traffic engineering (cont.)

  17. Traffic engineering (cont.)

  18. Traffic engineering (cont.)

  19. Conclusions • Unpredictable performance has been the most significant problem in the deployment of IP-based network. • IntServ , DiffServ and MPLS are all-important stepping stones in the evolution of a new IP infrastructure. • Important work has been ─ and continous to be under-taken ─ by the IETF working group.

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