2. June 4, 2003Carleton University & EIONGMPLS - 1 GMPLS Generalized Multiprotocol Label Switching Vijay Mahendran Sumita Ponnuchamy Christy Gnanapragasam

3. June 4, 2003Carleton University & EIONGMPLS - 2 Outline Background –Terminology – Optical Network Architectures –MPLS GMPLS Signaling –General Signaling –CR-LDP/RSVP

4. June 4, 2003Carleton University & EIONGMPLS - 3 Terminology 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

5. June 4, 2003Carleton University & EIONGMPLS - 4 ? 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) UNI Peer

6. June 4, 2003Carleton University & EIONGMPLS - 5 MPLS 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 Control: IP Router Software Control: IP Router Software Forwarding: Longest-match Lookup Control: ATM Forum Software Forwarding: Label Swapping IP Router MPLS ATM Switch Forwarding: Label Swapping

7. June 4, 2003Carleton University & EIONGMPLS - 6 1a. Routing protocols (e.g. OSPF-TE, IS-IS-TE) exchange reachability to destination networks 1b. Label Distribution Protocol (LDP) establishes label mappings to destination network 2. Ingress LER receives packet and “label”s packets IP 10 3. LSR forwards packets using label swapping IP 20 IP 40 4. LER at egress removes label and delivers packet IP MPLS Operation

8. June 4, 2003Carleton University & EIONGMPLS - 7 GMPLS 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

9. June 4, 2003Carleton University & EIONGMPLS - 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 FSC LSC TDMC PSC

10. June 4, 2003Carleton University & EIONGMPLS - 9 Key Extension To MPLS 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

11. June 4, 2003Carleton University & EIONGMPLS - 10 GMPLS Control Plane 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

12. June 4, 2003Carleton University & EIONGMPLS - 11 GMPLS Scalability Unnumbered Links –No IP –Specify unnumbered links: local ID Exchange local ID (signaling protocol) –Carry TE info about unnumbered links new sub-TLVs

13. June 4, 2003Carleton University & EIONGMPLS - 12 Bundled Link 2 Bundled Link 1 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 Link Bundling

14. June 4, 2003Carleton University & EIONGMPLS - 13 Link Management Procedures between LSRs: –Management –Verification –Property Correlation –Fault Management

15. June 4, 2003Carleton University & EIONGMPLS - 14 Generalized Signaling 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

16. June 4, 2003Carleton University & EIONGMPLS - 15 Signaling Protocols 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

17. June 4, 2003Carleton University & EIONGMPLS - 16 GMPLS Features New generic label request format Labels for TDM/LSC/FSC interfaces Specific traffic parameters per technology Bi-directional LSP establishments Ingress/Egress binding

18. June 4, 2003Carleton University & EIONGMPLS - 17 LSP Request 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

19. June 4, 2003Carleton University & EIONGMPLS - 18 Response for LSP Request Resv/Label Mapping message sent by the downstream LSR –Generalized Label object Several Generalized Labels –List of labels: SONET/SDH

20. June 4, 2003Carleton University & EIONGMPLS - 19 GMPLS - Signaling 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.

21. June 4, 2003Carleton University & EIONGMPLS - 20 Enhancements to Signaling 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

22. June 4, 2003Carleton University & EIONGMPLS - 21 Suggested Label =  Program Switch  X  Suggested Label =  Reserved Label =  Reserved Label =  Make sure the programming request has completed Request Program Switch  X  Request Map Label =  Map Label =  No suggested label with suggested label 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

23. June 4, 2003Carleton University & EIONGMPLS - 22 Suggested Label =  Upstream Label = a Suggested Label =  Upstream Label = b Reserved Label =  Reserved Label =  a b   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

24. June 4, 2003Carleton University & EIONGMPLS - 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

25. June 4, 2003Carleton University & EIONGMPLS - 24 LSP Nesting

26. June 4, 2003Carleton University & EIONGMPLS - 25 GMPLS – Nested Signaling

27. June 4, 2003Carleton University & EIONGMPLS - 26 Protection 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

28. June 4, 2003Carleton University & EIONGMPLS - 27 CR-LDP/RSVP-TE

29. June 4, 2003Carleton University & EIONGMPLS - 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

30. June 4, 2003Carleton University & EIONGMPLS - 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

31. June 4, 2003Carleton University & EIONGMPLS - 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

32. June 4, 2003Carleton University & EIONGMPLS - 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)

33. June 4, 2003Carleton University & EIONGMPLS - 32 #963 #14 #99 #311 #462 D #311 D #963 D #14 D #99 D #216 D #612 D #5 D Unsolicited Mode

34. June 4, 2003Carleton University & EIONGMPLS - 33 #963 #14 #99 #311 #462 D #311 D #963 D #14 D #99 D #216 D #612 D #5 D D? On Demand Mode

35. June 4, 2003Carleton University & EIONGMPLS - 34 #462 D #311 D #963 D #14 D #99 D #216 D #612 D #5 D #422 D #622 D These labels are kept in case they are needed after a failure. LIBERAL RETENTION

36. June 4, 2003Carleton University & EIONGMPLS - 35 #462 D #311 D #963 D #14 D #99 D #216 D #612 D #5 D #422 D #622 D These labels are released the moment they are received. CONSERVATIVE RETENTION

37. June 4, 2003Carleton University & EIONGMPLS - 36 POP 10.1.1. 1 10.1.1. 4 10.1.1. 3 Explicit route 10.1.1.7 strict 10.1.1.6 strict 10.1.1.2 loose 10.1.1.1 loose Strict hop LSP takes direct route to 10.1.1.7 Loose hop LSP takes shortest path to 10.1.1.2 10.1.1. 2 10.1.1. 6 10.1.1. 7 10.1.1. 5 Explicit route example

38. June 4, 2003Carleton University & EIONGMPLS - 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)

39. June 4, 2003Carleton University & EIONGMPLS - 38 #216 #14 #462 #972 A B C Route= {A,B,C} PREEMPTION

40. June 4, 2003Carleton University & EIONGMPLS - 39 RSVP-TE Vs. CR-LDP 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!

41. June 4, 2003Carleton University & EIONGMPLS - 40 TIME NODE A NODE B NODE A NODE B RSVP LDP/CR-LDP REQUESTPATH MAPPING RESV THAT’S ALL!! FOREVER !! RSVP Vs. CR-LDP

42. June 4, 2003Carleton University & EIONGMPLS - 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

43. June 4, 2003Carleton University & EIONGMPLS - 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

44. June 4, 2003Carleton University & EIONGMPLS - 43 References 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.pdfhttp://www- classes.usc.edu/engr/ee-s/650/Lecture%20note/GMPLS- Presentation%20by%20Gavin.pdf

45. June 4, 2003Carleton University & EIONGMPLS - 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/http://www.nanog.org/mtg-0110/ppt/shepherd/ RFCs : 3471,3472, and 3473

46. June 4, 2003Carleton University & EIONGMPLS - 45 Thank You