1. 1 Network Architecture and Design Internet QoS Differentiated Services (DiffServ) Multiprotocol Label Switching (MPLS) Reference Zheng Wang, Internet QoS, Architectures and Mechanisms for QoS, ISBN 1-55860-608-4, 2001.

2. 2 Network Architecture and Design DiffServ - Overview Integrated services provides QoS; but Problem of scalability The routers have to maintain state on every flow passing through them. Heterogeneous networks may not be able to provide particular QoS controls or even RSVP. Differentiated service (DiffServ) aims to offer QoS to aggregated flows.

3. 3 Network Architecture and Design DiffServ - Overview DiffServ defines Differentiated Service Code Point (DSCP) in IPv4 TOS field, IPv6 Traffic Class field. All traffic in one DSCP is treated the same. Per hop behaviour (PHB) is determined by DSCP of packet. Service Level Agreements concern aggregate traffic not individual flows.

4. 4 Network Architecture and Design DiffServ - Operation classifiermarker meter Shaper/ dropper To interior nodes Input

5. 5 Network Architecture and Design DiffServ - Traffic conditioning Classifier Marks packets according to classification rules. Meter Checks whether the traffic falls within the negotiated profile. Marker Marks traffic that falls within profile. Shapper/Dropper Delays and then forwards, discards, or remarks traffic.

6. 6 Network Architecture and Design DiffServ - Operation 2-Bit Differentiated Services Architecture for the Internet Premium service Premium service levels are specified as a desired peak bit rate for a specific flow Assured service Best-effort service

7. 7 Network Architecture and Design DiffServ - Operation Like leaky bucket with 2-bit designators (not just CLP setting). By software not built into hardware. In-profile traffic is marked: A-bit is set in every packet Out-of-profile (excess) traffic is unmarked A-bit is cleared (if it was previously set) in every packet; this traffic treated as best-effort r bps b bits metering in-profile traffic out-of-profile traffic user profile (token bucket) set A-bit clear A-bit assured traffic

8. 8 Network Architecture and Design DiffServ - Operation In-profile traffic marked: Set P-bit in each packet Out-of-profile traffic is delayed, and when buffer overflows it is dropped r bps b bits Metering/ Shaper/ Set P-bit in-profile traffic out-of-profile traffic (delayed and dropped) premium traffic user profile (token bucket)

9. 9 Network Architecture and Design Problems of DiffServ Does not support dynamic reservations only static. Scalable, but provides weaker services than IntServ (due to aggregation). It is not yet clear what kind of guarantees can be given to end-to-end services (how to translate user-QoS to net-QoS?). Missing of standardized resource management in every node. Solution: Bandwidth Broker (BB)

10. 10 Network Architecture and Design Bandwidth Broker (BB) The BB performs three distinct tasks: Negotiation of SLAs with BBs of neighbouring domains Translation of SLAs into one or several Traffic Control Agreements (TCAs) for edge devices Delivery of the TCAs to the edge routers of the administered domain

11. 11 Network Architecture and Design IntServ Vs DiffServ Integrated Services Differentiated Services QoS guaranteePer data streamAggregated data streams ConfigurationPer session end- to end Between domains Duration of guarantee Short-livedLong-term SignalingRSVPNot yet defined

12. 12 Network Architecture and Design IntServ Vs DiffServ IntServ provides fine grain control and handles dynamic allocation of resources to flows DiffServ provides course grain control of flows through their aggregates The two together can be combined to provide scalable end to end Integrated service, using a DiffServ region as a single element Controlled Load can be implemented over Assured Forwarding PHB Guaranteed can be implemented over Expedited Forwarding PHB

13. 13 Network Architecture and Design IntServ & DiffServ

14. 14 Network Architecture and Design Internet QoS Differentiated Services (DiffServ) Multiprotocol Label Switching (MPLS)

15. 15 Network Architecture and Design MPLS Overview MPLS (Multiprotocol Label Switching) Improves the forwarding speed of a router. Introduces new capabilities for large IP networks Introduction of many of the qualities and attributes of switched networks to IP networks Integrates Layers 2 and 3.

16. 16 Network Architecture and Design MPLS Operation MPLS Components Edge-LSR: Edge-Label Switching Router Assigns a label in an incoming IP packet Removes the label of an incoming IP packet LSP: Label Switching Path The path that a packet follows in an MPLS network LSR: Label Switching Router Makes forwarding decisions based SOLELY on the contents of the label (basic advantage) Strips off the existing label and applies a new label which tells the next hop how to forward the packet

17. 17 Network Architecture and Design MPLS – Traditional IP Routing 47.1 47.2 47.3 IP 47.1.1.1 1 2 3 1 2 1 2 3

18. 18 Network Architecture and Design MPLS – MPLS Routing 47.1 47.2 47.3 1 2 3 1 2 1 2 3 3 IP 47.1.1.1

19. 19 Network Architecture and Design MPLS Label Format IP packet is encapsulated in MPLS header and sent down LSP IP packet is restored at end of LSP by egress router TTL is adjusted also … IP Packet 32-bit MPLS Header

20. 20 Network Architecture and Design MPLS Label format TTLLabelCoSS Label Class of service Stacking bit Time to live Decrement at each LSR, or Pass through unchanged

21. 21 Network Architecture and Design MPLS Fast forwarding speed Traffic Engineering constraint-based routing explicit routing ability to compute a path at the source ability to reserve network resources and to modify link attributes Voice/Video on IP delay variation + QoS constraints Virtual Private Networks controllable tunneling mechanism equivalent to a Frame Relay or ATM VC

22. 22 Network Architecture and Design Second Intermediate Report Multicast Routing (Focus on Internet Technology) Doukas Multicast Routing (Focus on Wireless Technologies) Kikilis MBONE Mavrogenis IntServ (Focus on IntServ Implementation) Klaoudatou IntServ (Focus on support of IntServ over other technologies, i.e., ATM, wireless) Barbarousis Diffserv (Focus on Diffserv Implementation) Ratsiatos

23. 23 Network Architecture and Design Second Intermediate Report Diffserv (Focus on support of DiffServ over other technologies, i.e., ATM, DVB) Panoutsakopoulos Integration of IntServ and Diffserv Lizos MPLS (Focus on Routing) Kolovou MPLS (Focus on Admission Control) Baliotis SLAs/SLSs Rekleitis Protocols for inter-BB communication Plataniwtis

24. 24 Network Architecture and Design Second Intermediate Report Structure Overview of examined technology Focus on open research points Related to open points works - State of the art behind open points Your own interests - Ideas Conclusions References

25. 25 Network Architecture and Design Second Intermediate Report Report (soft and hard copy) A related presentation (about twenty minutes) Usage of Greek language Deadline: 26/04/03

26. 26 Network Architecture and Design End of Fourth Lecture