GMPLS

1. Generalized Multiprotocol Label Switching GMPLS Vijay Mahendran Sumita Ponnuchamy Christy Gnanapragasam Carleton University & EION

2. Background Terminology Optical Network Architectures MPLS GMPLS Signaling General Signaling CR-LDP/RSVP Outline Carleton University & EION

3. MPLS – Multi-Protocol Label Switching GMPLS – Generalized MPLS LSR – Label Switched Router LER – Label Edge Router LSP – Label Switched Path RSVP-TE – Resource Reservation Protocol with Engineering CR-LDP – Constraint Based Label Distribution OSPF – Open Shortest Path First IS-IS – Intermediate System to Intermediate UNI – User-Network Interface NNI – Network-Network Interface DWDM – Dense Wavelength Division Multiplexing OXC – Optical Cross-Connect LMP – Link Management Protocol Terminology Carleton University & EION

4. ? Peer UNI Optical Network Architectures • Overlay model • Two independent control planes • Optical domain & IP/MPLS routing • Router is client of optical domain • Optical topology invisible to routers • Peer model • Single integrated control plane • Router and optical switches are peers • Optical topology is visible to routers • Hybrid model • Multi admin domain support (overlay) • Multiple technologies within domain (peer) Carleton University & EION

5. Speed of Layer 2 switching in Layer 3 AIM : Establish the Forwarding Table Link state routing protocols Exchange network topology information for path selection OSPF-TE, IS-IS-TE Signaling/Label distribution protocols: Set up LSP (Label Switched Path) LDP, RSVP-TE, CR-LDP MPLS ATM Switch IP Router Forwarding: Label Swapping Control: Control: Control: IP Router Software IP Router Software ATM Forum Software Forwarding: Forwarding: Longest-match Lookup Label Swapping MPLS Carleton University & EION

6. MPLS Operation 1a. Routing protocols (e.g. OSPF-TE, IS-IS-TE) exchange reachability to destination networks 4. LER at egress removes label and delivers packet 1b. Label Distribution Protocol (LDP) establishes label mappings to destination network 10 20 40 IP IP IP IP IP 2. Ingress LER receives packet and “label”s packets 3. LSR forwards packets using label swapping Carleton University & EION

7. Extend MPLS to cover the Optical Domain Packet Switch Capable (PSC) Layer 2 Switch Capable (L2SC) Time Division Multiplexing Capable (TDMC) Lambda Switch Capable (LSC) Fiber Switch Capable (FSC) A common control plane Support multiple types of traffic (ATM, IP, SONET and etc.) Support both peer and overlay models Support multi-vendors Perform fast provisioning GMPLS Carleton University & EION

8. GMPLS is deployed from MPLS Apply MPLS control plane techniques to optical switches IP routing algorithms to manage light paths in an optical network GMPLS made some modifications on MPLS Separation of Control and Data planes Support multiple interface Enable nesting of different interfaces PSC TDMC LSC FSC TDMC LSC Carleton University & EION

9. Label encoded as timeslots, wavelengths, position in real world LSP start & end on similar interfaces Suggested Labels by upstream node Label restrictions Bi-directional LSPs Support rapid failure notification BW allocation in discrete time Extended payload encoding Key Extension To MPLS Carleton University & EION

10. Extension of MPLS control plane GMPLS extends OSPF-TE and IS-IS-TE for routing GMPLS extends RSVP-TE and CR-LDP for signaling Control Channels in-band or out-of-band LMP- Link Management Protocol Extension to MPLS-TE GMPLS Control Plane Carleton University & EION

11. Unnumbered Links No IP Specify unnumbered links: local ID Exchange local ID (signaling protocol) Carry TE info about unnumbered links new sub-TLVs GMPLS Scalability Carleton University & EION

12. Bundled Link 1 Link Bundling Bundled Link 2 • Multiple parallel links between nodes can be advertised as a single link into the IGP • Enhances IGP and traffic engineering scalability • Component links must have the same • Link type • Traffic engineering metric • Set of resource classes • Link multiplex capability (packet, TDM, λ, port) • Max BW request  BW of a component link • Link granularity can be as small as a λ Carleton University & EION

13. Procedures between LSRs: Management Verification Property Correlation Fault Management Link Management Carleton University & EION

14. Allow establishments of PATHs ATM/FR labeled paths Time division multiplexed paths Frequency division multiplexed paths Space division multiplexed paths GMPLS Signaling CR-LDP and RSVP-TE Extends based functions Add functionalities Generalized Signaling Carleton University & EION

15. Label Distribution Protocol (LDP) establishes label-to-destination network mappings CR-LDP extended from LDP to for G/MPLS RSVP - QoS reservations between hosts RSVP Extensions for GMPLS Concept of labels and LSPs Explicit routes LSP attributes Setup and Holding priorities Signaling Protocols Carleton University & EION

16. New generic label request format Labels for TDM/LSC/FSC interfaces Specific traffic parameters per technology Bi-directional LSP establishments Ingress/Egress binding GMPLS Features Carleton University & EION

17. Send PATH/Label Request downstream Type of LSP Payload type BW encoding SENDER_TSPEC: RSVP-TE Traffic Parameter TLV: CR-LDP Protection Bi-directional LSP support Specify upstream label Suggested labels LSP Request Carleton University & EION

18. Resv/Label Mapping message sent by the downstream LSR Generalized Label object Several Generalized Labels List of labels: SONET/SDH Response for LSP Request Carleton University & EION

19. Generalized Label Request the encoding of label requested the type of switching required Generalized Label In addition to representing a packet a label can represent a number of time slots a wavelength a set of contiguous wavelengths (waveband) Etc. GMPLS - Signaling Carleton University & EION

20. Suggested Label Label suggestion from upstream node Reduction in setup latency Important for restoration Restricted Labels provide upstream node with control over chosen labels limit the choice of labels to the downstream node Bi-directional LSP demand for bidirectional LSPs in support of TDM and Lambda switching Both directions have same traffic engineering requirements Enhancements to Signaling Carleton University & EION

21. Request Request Map Label = l1 Suggested Label = l1 Map Label = l2 Suggested Label = l2 Reserved Label = l4 Reserved Label = l3 Suggested label • Problem: • it takes time for the optical switch to program switch Long setup time • Solution: • Each LSR selects a label (Suggested Label) and signals this label to downstream LSR, and start program its switch. • reduce LSP setup overhead Program Switch l1 X l2 Make sure the programming request has completed Program Switch l1 X l2 No suggested label with suggested label Carleton University & EION

22. Suggested Label = l2 Upstream Label = lb Suggested Label = l1 Upstream Label = la l4 l3 lb la Reserved Label = l4 Reserved Label = l3 Bi-Directional LSP setup • Problem: • How to set up bi-directional LSP? • Solution: • Set up 2 uni-directional LSP • Signaling overhead • End points coordination • One single message exchange for one bi-directional LSP • Upstream label Carleton University & EION

23. Enhancements to Signaling • Notification • Notify message added to RSVP-TE for GMPLS • This message for link failures • Nested LSPs • allows the system to scale by building a forward hierarchy • At the top of hierarchy are FSC interfaces, then LSC, TDM, and PSC interfaces • Protection • protection information in a new object, specifying the LSP is the primary or secondary one • the desired protection type Carleton University & EION

24. LSP Nesting Carleton University & EION

25. GMPLS – Nested Signaling Carleton University & EION

26. Link protection Protection capability Attributes None, 1:1, 1+1, 1:N, or ring Priority for a working channel 1:1 Protection Working Protection 1:N Protection Working Protection Protection Carleton University & EION

27. CR-LDP/RSVP-TE Carleton University & EION

28. RSVP-TE Details • RSVP-TE is an extension of “classical” RSVP • Runs directly over IP • Uses Path messages (= Label Request) and Resv messages (= Label Mapping) • Extends classical RSVP with new objects • (= (Type,length,value) TLVs) for these messages • Explicit Route Object (ERO) contains hops Carleton University & EION

29. CR-LDP details • CR-LDP is an extension to LDP • Like LDP, runs over TCP • Uses existing LDP messages, but defines additional TLVs for the messages • LSR Discovery • Multicast HELLO to well-known UDP port on “all routers on this subnet” multicast group • Can also send to configured IP addresses • Make TCP connection upon response Carleton University & EION

30. Common features • Operate in (Downstream-on-Demand, Conservative, Ordered) mode • Features: • Explicit route • QoS specification • LSP preemption • LSP modification • LDP sets up LSPs automatically, while CR-LDP and RSVP-TE typically require some sort of external intervention Carleton University & EION

31. CR-LDP and RSVP-TE • Used to set up point-to-point LSPs • LSPs can follow any path • Can specify QoS parameters for LSP • Useful for: • Traffic Engineering of Public Internet traffic • Traffic Engineering of VPN tunnels • Automatic Setup of Light Paths in Automatically • Switched Optical Networks (ASON) Carleton University & EION

32. #14 #311 #216 #99 #311 #963 #311 D #963 #14 #612 D #462 D D D #311 #99 #5 D D D Unsolicited Mode Carleton University & EION

33. #14 #311 #216 #99 #311 #963 #311 D D? D? #963 #14 D? D? #612 D D? #462 D D? D D #311 #99 #5 D D D D? D? On Demand Mode Carleton University & EION

34. #216 D D #963 #14 #622 #612 D #462 D D D D #311 #422 #99 #5 D D D LIBERAL RETENTION These labels are kept in case they are needed after a failure. Carleton University & EION

35. #216 D D #963 #14 #622 #612 D #462 D D D D #311 #422 #99 #5 D D D CONSERVATIVE RETENTION These labels are released the moment they are received. Carleton University & EION

36. Explicit route example Loose hopLSP takes shortestpath to 10.1.1.2 10.1.1.1 10.1.1.2 10.1.1.3 10.1.1.5 10.1.1.6 10.1.1.4 10.1.1.7 Explicit route 10.1.1.7 strict10.1.1.6 strict10.1.1.2 loose10.1.1.1 loose Strict hopLSP takes direct route to 10.1.1.7 POP Carleton University & EION

37. ER LSP - advantages • Operator has routing flexibility (policy-based, QoS-based) • Can use routes other than shortest path • Can compute routes based on constraints in exactly the same manner as ATM based on distributed topology database.(traffic engineering) Carleton University & EION

38. Route={A,B,C} #216 #14 #972 #462 PREEMPTION B C A Carleton University & EION

39. RSVP-TE uses raw IP, while CR-LDP uses TCP to distribute labels and UDP to discover neighbors High Availability: RSVP-TE lends itself well to a system that must survive hardware failure or online software updates. CR-LDP assumes reliable delivery of messages and so is not well placed to survive failover RSVP-TE is a soft state protocol, needing periodically refreshing Failure notification: only RSVP-TE provides failure notification, not CR-LDP! RSVP-TE Vs. CR-LDP Carleton University & EION

40. NODEA NODEB NODEA NODEB PATH REQUEST MAPPING PATH RESV PATH PATH RESV RESV RESV PATH RESV RSVP Vs. CR-LDP RSVP LDP/CR-LDP THAT’S ALL!! FOREVER!! TIME Carleton University & EION

41. RSVP-TE:Refresh reduction • Each Path and Resv message must be • refreshed • In a network with many LSPs, this requires • lots of messages • Hence the Refresh Reduction Extension • This allows a router to send a single compact message that refreshes lots of LSPs at once Carleton University & EION

42. Summary • GMPLS is an extension of MPLS: • PSC • TDMC • LSC • FSC • GMPLS Signaling • Establish Forwarding State • Label Distribution • CR-LDP/RSVP- two signaling protocols • essentially the same functionality Carleton University & EION

43. Generalized Multi-Protocol Label Switching Architecture (draft-ietf-ccamp-gmpls-architecture-07.txt) Ayan Banerjee, John Drake, Jonathan P. Lang, Brad Turner, Kireeti Kompella, and Yakov Rekhter, “Generalized Multiprotocol Label Switching: An Overview of Routing and Management Enhancements” IEEE Communications Magazine, January 2001. Mark J. Francisco “Generalized Multiprotocol Switching” Advanced Optical Networks Laboratory Carleton University January, 2002 Generalized MPLS - Generalized MPLS -Signaling Functional Signaling Functional Description (draft-ashwoodgeneralized-mpls-signaling-00.txt) Gavin Gandhi “Generalized MultiProtocol Label Switching”, University of Southern California. Available at http://www-classes.usc.edu/engr/ee-s/650/Lecture%20note/GMPLS-Presentation%20by%20Gavin.pdf References Carleton University & EION

44. Ayan Banerjee, John Drake, Jonathan Lang, Brad Turner, Daniel Awduche, Lou Berger, Kireeti Kompella, Yakov Rekhter, “ Generalized Multiprotocol Label Switching: An Overview of Signaling Enhancements and Recovery Techniques”, IEEE Communications Magazine • July 2001. Li Yin, “MPLS and GMPLS” Available at www.cs.berkeley.edu/~randy/Courses/cs294.s02/MPLS.ppt Peter Ashwood-Smith and Bilel Jamoussi, “MPLS Tutorial and Operational Experiences”, October, 1999. Available at http://www.nanog.org/mtg-9910/ppt/peter.ppt Packets & Photons: The Emerging Two Layer Network”, October 2001. Available at http://www.nanog.org/mtg-0110/ppt/shepherd/ RFCs : 3471,3472, and 3473 Carleton University & EION

45. Thank You Carleton University & EION