2. 1 © 1999, Cisco Systems, Inc. Mosaddaq Turabi MPLS Traffic Engineering -SESSION A- (MPLS BOOTCAMP) Mosaddaq Turabi (mturabi@cisco.com) MPLS Traffic Engineering -SESSION A- (MPLS BOOTCAMP) Mosaddaq Turabi (mturabi@cisco.com)

3. 2 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. What is Traffic Engineering? “Traffic Engineering is the process of controlling how traffic flows through one’s network so as to optimize resource utilization and network performance” (Global Crossing, IEEE)

4. 3 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Traffic Engineering: Motivations Reduce the overall cost of operations by more efficient use of bandwidth resources – by preventing a situation where some parts of a service provider network are over-utilized (congested), while other parts under-utilized cost saving ! The ultimate goal is cost saving !

5. 4 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. The “Overlay” Solution Routing at layer 2 (ATM or FR) is used for traffic engineering Full mesh of VCs between routers; each router has a direct VC to every other router in the mesh L3 L3 L3 L3 L3 L3 L3 L2 L2 L2 L2 L2 L2 L3 L3 L3 L3L3 PhysicalLogical

6. 5 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Traffic Engineering with Overlay R1 R2 R4 R3 TRAFFIC ENGINEERING AT LAYER 2 R1 L2 L2L2 L2 R2 R4R3 R1 L2 L2L2 L2 R2 R4R3 R1 R2 R4 R3 R1’s VIEW OF THE NETWORK AT LAYER3

7. 6 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. “Overlay” Solution: Drawbacks Extra network devices (cost) More complex network management (cost) – two-level network without integrated network management – additional training, technical support, field engineering IGP routing scalability issue for meshes Additional bandwidth overhead (“cell tax”)

8. 7 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Issues with IGP Routing IGPs forward packets based on shortest path (metric). Flows from multiple sources may go over some common link(s) causing congestion. Alternate longer and underutilized path will not be used. IGP metric change may have side effects.

9. 8 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Traffic Engineering With Layer 3 R2 R3 R1 IP routing: destination-based least-cost routing under-utilized alternate path Path for R2 to R3 traffic Path for R1 to R3 traffic

10. 9 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Traffic Engineering with Layer 3 R2 R3 R1 IP routing: destination-based least-cost routing under-utilized alternate path Path for R2 to R3 traffic Path for R1 to R3 traffic

11. 10 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Traffic Engineering with Layer 3 What is Missing ? Path computation based just on IGP metric is not enough Packet forwarding in IP network is done on a hop by hop basis, derived from IGP Support for “explicit” routing (aka “source routing”) is not available

12. 11 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Routing Solution to Traffic Engineering Construct routes for traffic streams within a service provider in such a way as to avoids causing some parts of the provider’s network to be over-utilized, while others parts remain under- utilized R2 R3 R1

13. 12 © 1999, Cisco Systems, Inc. Mosaddaq Turabi MPLS Traffic Engineering 12 © 1999, Cisco Systems, Inc.

14. 13 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. TE - KEY COMPONENTS - Be able to set up a LSP based on BW availability (RSVP) - Be able to set up a LSP based on user defined policies (Explicit Path or Link resource-class attribute string) - Flooding of resource availability and policies to all the routers in the network (IS-IS or OSPF) - Be able to run C-SPF based on constraints defined by a user - MPLS as the forwarding mechanism

15. 14 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. TE - KEY COMPONENTS R2 R3 R1 - RSVP (extensions) on all links to reserve and monitor reservations per LSP plus Label distribution - Resource-class attribute string (policy) defined on all links - IS-IS or OSPF (extensions) to flood policy and resource availability - C-SPF to find the path meeting the constraints

16. 15 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. TE - KEY COMPONENTS - TE tunnel (LSP) is initiated from the source (R1 and R2) - Source of TE tunnel (LSP) is called “Head End” (R1 and R2) - Destination of the TE tunnel (LSP) is called “Tail End” (R3) - All the intermediate LSR are called “Mid Points” - TE tunnel (LSP) is unidirectional and traffic flows from Head-end to the Tail- end R2 R3 R1

17. 16 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. What is a “traffic trunk” ? Aggregation of (micro) flows that are: – forwarded along a common path (within a service provider) – often from a POP to another POP Essential for scalability D AB C

18. 17 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. TE basics Traffic within a Service Provider as a collection of “POP to POP traffic trunks” with known bandwidth and policy requirements TE provides traffic trunk routing that meets the goal of Traffic Engineering – via a combination of on-line and off- line procedures

19. 18 © 1999, Cisco Systems, Inc. Mosaddaq Turabi MPLS TE REQUIREMENTS 18 © 1999, Cisco Systems, Inc.

20. 19 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Requirements Differentiating traffic trunks: – large, ‘critical’ traffic trunks must be well routed in preference to other trunks Handling failures: – automated re-routing in the presence of failures Pre-configured paths: – for use in conjunction with the off-line route computation procedures Support of multiple Classes of Service

21. 20 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Requirements (cont.) Constraining sub-optimality: – should re-optimize on new/restored bandwidth in a non-disruptive fashion - maintain the existing route until the new route is established, without any double counting Ability to “spread” traffic trunk across multiple Label Switched Paths (LSPs) – could provide more efficient use of networking resources Ability to include/exclude certain links for certain traffic trunks

22. 21 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Design Constraints Constrained to a single routing domain – initially constrained to a single area Requires OSPF or IS-IS Unicast traffic Focus on supporting routing based on a combination of administrative + bandwidth constraints

23. 22 © 1999, Cisco Systems, Inc. Mosaddaq Turabi Trunk Attributes 22 © 1999, Cisco Systems, Inc.

24. 23 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Trunk Attributes Configured at the head-end of the trunk Bandwidth Priorities – setup priority: priority for taking a resource – holding priority: priority for holding a resource

25. 24 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Trunk Attributes Ordered list of Path Options – possible administratively specified paths (via an off-line central server) - {explicit list} – Constrained-based dynamically computed paths based on combo of BW and policies Re-optimization – each path option is enabled or not for re- optimization, interval given in seconds. – Max 1 week (7*24*3600), Disable 0, Def 1h.

26. 25 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Trunk Attributes Resource class affinity (Policy) – supports the ability to include/exclude certain links for certain traffic trunks based on a user-defined Policy – Tunnel is characterized by a 32-bit resource-class affinity bit string 32-bit resource-class mask (0 = don’t care, 1 = care) – Link is characterized by a 32-bit resource-class attribute string – Default-value of tunnel/link bits is 0 – Default value of the tunnel mask = 0x0000FFFF

27. 26 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Example 1: 4-bit String, Default Trunk A to B: – tunnel = 0000, t-mask = 0011 ADEB and ADCEB are possible AB 0000 C DE

28. 27 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Example 1a: 4-Bit String Setting a link bit in the lower half drives all tunnels off the link, except those specially configured Trunk A to B: – tunnel = 0000, t-mask = 0011 Only ADCEB is possible AB 0000 0010 0000 C DE

29. 28 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Example 1b: 4-Bit String A specific tunnel can then be configured to allow such links by clearing the bit in its affinity attribute mask Trunk A to B: – tunnel = 0000, t-mask = 0001 Again, ADEB and ADCEB are possible AB 0000 0010 0000 C DE

30. 29 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Example 1c: 4-Bit String A specific tunnel can be restricted to only such links by instead turning on the bit in its affinity attribute bits Trunk A to B: – tunnel = 0010, t-mask = 0011 No path is possible AB 0000 0010 0000 C DE

31. 30 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Example 2a: 4-Bit String Setting a link bit in the upper half drives has no immediate effect Trunk A to B: – tunnel = 0000, t-mask = 0011 ADEB and ADCEB are both possible AB 0000 0100 0000 C DE

32. 31 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Example 2b: 4-Bit String A specific tunnel can be driven off the link by setting the bit in its mask Trunk A to B: – tunnel = 0000, t-mask = 0111 Only ADCEB is possible AB 0000 0100 0000 C DE

33. 32 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Example 2c: 4-Bit String A specific tunnel can be restricted to only such links Trunk A to B: – tunnel = 0100, t-mask = 0111 No path is possible AB 0000 0100 0000 C DE

34. 33 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Trunk Attribute Resource Class Affinity (Policy) The user defines the semantics: – this bit/mask says “low-delay path excluded” – this bit/mask says “use only links 0C-3 or higher” – this bit/mask says “use only links in region 1,2,3”

35. 34 © 1999, Cisco Systems, Inc. Mosaddaq Turabi Link Attributes and Their Flooding 34 © 1999, Cisco Systems, Inc.

36. 35 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Link Resource Attributes Resource attributes are configured on every link in a network – Bandwidth – Link Attributes – TE-specific link metric

37. 36 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Link Resource Attributes Resource attributes are flooded throughout the network – Bandwidth per priority (0-7) – Link Attributes (Policy) – TE-specific link metric

38. 37 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Per-Priority Available BW D T=0 Link L, BW=100 D advertises: AB(0)=100=…= AB(7)=100 AB(i) = “Available Bandwidth at priority I” D T=2 Link L, BW=100 D advertises: AB(0)=AB(1)=AB(2)=100 AB(3)=AB(4)=…=AB(7)=70 T=1 Set-up of a tunnel over L at priority=3 for 30 units D T=4 Link L, BW=100 D advertises: AB(0)=AB(1)=AB(2)=100 AB(3)=AB(4)=70 AB(5)=AB(6)=AB(7)=40 T=3 Set-up of an additional tunnel over L at priority=5 for 30 units

39. 38 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Information Distribution Re-use the flooding service from the Link-State IGP – opaque LSA for OSPF draft-katz-yeung-ospf-traffic-00.txt – new wide TLV for IS-IS draft-ietf-isis-traffic-00.txt

40. 39 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Information Distribution Periodic (timer-based) On significant changes of available bandwidth (threshold scheme) On link configuration changes On LSP Setup failure

41. 40 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Periodic Timer Periodically, a node checks if the current TE status is the same as the one last broadcasted If different, it floods its updated TE Links status

42. 41 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Significant Change Each time a threshold is crossed, an update is sent Denser population as utilization increases Different thresholds for Up and Down (stabler) 50% 100% 70% 85% 92% Update

43. 42 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. LSP Setup Failure Due to the threshold scheme, it is possible that one node thinks it can signal an LSP tunnel via node Z while in fact, Z does not have the required resources When Z receives the Resv message and refuses the LSP tunnel, it broadcasts an update of its status

44. 43 © 1999, Cisco Systems, Inc. Mosaddaq Turabi Constrained-Based Computation (C-SPF) 43 © 1999, Cisco Systems, Inc.

45. 44 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Constrained-Based Routing “In general, path computation for an LSP may seek to satisfy a set of requirements associated with the LSP, taking into account a set of constraints imposed by administrative policies and the prevailing state of the network -- which usually relates to topology data and resource availability. Computation of an engineered path that satisfies an arbitrary set of constraints is referred to as "constraint based routing”. Draft-li-mpls-igp-te-00.txt

46. 45 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Computation “On demand” by the trunk’s head-end: – for a new trunk – for an existing trunk whose (current) LSP failed – for an existing trunk when doing re- optimization

47. 46 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Computation Input: – configured attributes of traffic trunks originated at this router – attributes associated with resources available from IS-IS or OSPF – topology state information available from IS-IS or OSPF

48. 47 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Computation Prune links if: – insufficient resources (e.g., bandwidth) – violates policy constraints Compute shortest distance path – TE uses its own metric – Tie-break: selects the path with the highest minimum bandwidth so far, then with the smallest hop-count

49. 48 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Computation Output: – explicit route - expressed as a sequence of router IP addresses interface addresses for numbered links loopback address for unnumbered links – used as an input to the path setup component

50. 49 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. C-SPF Algorithm Prune off the links that do not have the required BW Prune off the links that do not have the required affinity Run a dijkstra on the remaining topology, optimised based on the IGP metric (or RRR metric if configured) If several paths are still available, then do the following to ultimately select a single path – choose the path that maximize the following value V V of a path is the minimum of the value L computed for each link. L on a link is the available bw at the required priority. This rule helps loadbalancing tunnels on various paths – If several paths are still available, then select the path with the smallest number of hops – If several paths are still available, select a random one

51. 50 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Tunnel’s request: – Priority 3, BW = 30 units, – Policy string: 0000, mask: 0011 AB 0000 1000 0100 0000 C D E 1000 0010 G BW(3)=60 BW(3)=50 BW(3)=80 BW(3)=20 BW(3)=50 BW(3)=70 BW(3)=80 BW/Policy Example

52. 51 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Tunnel’s request: – Priority 3, BW = 30 units, – Policy string: 0000, mask: 0011 AB C D E G BW(3)=60 BW(3)=80 BW(3)=50 BW(3)=40 BW(3)=80 Tightest Constraint: 40 Tightest Constraint: 60 Maximizing the Tightest Constraint

53. 52 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Load-Balancing Tunnels all tunnels require 10 AB C D E G BW(3)=100 BW(3)=200 BW(3)=100 BW(3)=200

54. 53 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Load-Balancing Tunnels all tunnels require 10 AB C D E G BW(3)=90 BW(3)=190 BW(3)=90 BW(3)=100 BW(3)=190

55. 54 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Load-Balancing Tunnels all tunnels require 10 AB C D E G BW(3)=90 BW(3)=180 BW(3)=90 BW(3)=180

56. 55 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Load-Balancing Tunnels all tunnels require 10 AB C D E G BW(3)=80 BW(3)=170 BW(3)=80 BW(3)=90 BW(3)=170

57. 56 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Load-Balancing Tunnels all tunnels require 10 AB C D E G BW(3)=80 BW(3)=160 BW(3)=80 BW(3)=160

58. 57 © 1999, Cisco Systems, Inc. Mosaddaq Turabi MPLS as the Forwarding Mechanism 57 © 1999, Cisco Systems, Inc.

59. 58 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. MPLS Labels Two types of MPLS Labels: Prefix Labels & Tunnel Labels LDP RSVP MP-BGP CR-LDP PIM Distributed by:

60. 59 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. MPLS as Forwarding Engine Traffic engineering requires explicit routing capability IP supports only the destination-based routing – not adequate for traffic engineering MPLS provides simple and efficient support for explicit routing – label swapping – separation of routing and forwarding

61. 60 © 1999, Cisco Systems, Inc. Mosaddaq Turabi LSP Tunnel Setup 60 © 1999, Cisco Systems, Inc.

62. 61 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. RSVP Extensions to RFC2205 for LSP Tunnels Downstream-on-demand label distribution Instantiation of explicit label switched paths Allocation of network resources (e.g., bandwidth) to explicit LSPs Re-routing of established LSP-tunnels in a smooth fashion using the concept of make-before-break Tracking of the actual route traversed by an LSP-tunnel Diagnostics on LSP-tunnels The concept of nodal abstraction Pre-emption options that are administratively controllable draft-ietf-mpls-rsvp-lsp-tunnel-0X.txt

63. 62 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. RSVP Extensions: New Objects LABEL_REQUESTLABEL_REQUEST found in Path LABELLABEL EXPLICIT_ROUTEEXPLICIT_ROUTE found in Path RECORD_ROUTERECORD_ROUTE found in Path, Resv SESSION_ATTRIBUTESESSION_ATTRIBUTE found in Path 0x01 Fast Re-route Capable, 0x02 Permit Merging, 0x04 May Reoptimize => SE SESSION SENDER_TEMPLATEFILTER_SPECFLOWSPECNew C-Types are also assigned for the SESSION, SENDER_TEMPLATE, FILTER_SPEC, FLOWSPEC objects All new objects are optional with respect to RSVP (RFC2205) The LABEL_REQUEST and LABEL objects are mandatory with respect to MPLS LSP signalisation specification

64. 63 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. LSP Setup Initiated at the head-end of a trunk Uses RSVP (with extensions) to establish Label Switched Paths (LSPs) for traffic trunks

65. 64 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Setup - Example Setup: Path (ERO = R1->R2->R6->R7->R4->R9) Reply: Resv communicates labels and reserves bandwidth on each link Pop Label 22 Label 49 Label 17 R8 R2 R6 R3 R4 R7 R1 R5 R9 Label 32

66. 65 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Setup - More Details R2 R3 R1 Path: Common_Header Session(R3-lo0, 0, R1-lo0) PHOP(R1-2) Label_Request(IP) ERO (R2-1, R3-1) Session_Attribute (S(3), H(3), 0x04) Sender_Template(R1-lo0, 00) Sender_Tspec(2Mbps) Record_Route(R1-2) 22 1 1

67. 66 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Setup - More Details R3 R1 Path State: Session(R3-lo0, 0, R1-lo0) PHOP(R1-2) Label_Request(IP) ERO (R2-1, R3-1) Session_Attribute (S(3), H(3), 0x04) Sender_Template(R1-lo0, 00) Sender_Tspec(2Mbps) Record_Route (R1-2) 2 1 R2 2 1

68. 67 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Setup - More Details R3 R1 Path: Common_Header Session(R3-lo0, 0, R1-lo0) PHOP(R2-2) Label_Request(IP) ERO (R3-1) Session_Attribute (S(3), H(3), 0x04) Sender_Template(R1-lo0, 00) Sender_Tspec(2Mbps) Record_Route (R1-2, R2-2) 2 1 R2 2 1

69. 68 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Setup - More Details R3 R1 2 1 R2 2 1 Path State: Session(R3-lo0, 0, R1-lo0) PHOP(R2-2) Label_Request(IP) ERO () Session_Attribute (S(3), H(3), 0x04) Sender_Template(R1-lo0, 00) Sender_Tspec(2Mbps) Record_Route (R1-2, R2-2, R3-1)

70. 69 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Resv: Common_Header Session(R3-lo0, 0, R1-lo0) PHOP(R3-1) Style=SE FlowSpec(2Mbps) Sender_Template(R1-lo0, 00) Label=POP Record_Route(R3-1) Path Setup - More Details R3 R1 2 1 R2 2 1

71. 70 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Setup - More Details R3 R1 2 1 R2 2 1 Resv State Session(R3-lo0, 0, R1-lo0) PHOP(R3-1) Style=SE FlowSpec (2Mbps) Sender_Template(R1-lo0, 00) OutLabel=POP IntLabel=5 Record_Route(R3-1)

72. 71 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Setup - More Details R3 R1 2 1 R2 2 1 Resv: Common_Header Session(R3-lo0, 0, R1-lo0) PHOP(R2-1) Style=SE FlowSpec (2Mbps) Sender_Template(R1-lo0, 00) Label=5 Record_Route(R2-1, R3-1)

73. 72 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Setup - More Details R3 R1 2 1 R2 2 1 Resv state: Session(R3-lo0, 0, R1-lo0) PHOP(R2-1) Style=SE FlowSpec (2Mbps) Sender_Template(R1-lo0, 00) Label=5 Record_Route(R1-2, R2-1, R3-1)

74. 73 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Trunk Admission Control Performed by routers along a Label Switched Path (LSP) Determines if resources are available May tear down (existing) LSPs with a lower priority Does the local accounting Triggers IGP information distribution when resource thresholds are crossed

75. 74 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Link Admission Control Already invoked by Path message – if BW is available, this BW is put aside in a waiting pool (waiting for the RESV msg) – if this process required the pre-emption of resources, LCAC notified RSVP of the pre-emption which then sent PathErr and/or ResvErr for the preempted tunnel – if BW is not available, LCAC says “No” to RSVP and a Path error is sent. A flooding of the node’s resource info is triggered, if needed – “draft-ietf-mpls-rsvp-lsp-tunnel-02.txt”

76. 75 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Monitoring Use of new Record Route Object – keep track of the exact tunnel path – detects loops

77. 76 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Path Re-Optimization Looks for opportunities to re-optimize – make before break – no double counting of reservations – via RSVP “shared explicit” style!

78. 77 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Non-Disruptive Rerouting - New Path Setup Current Path (ERO = R1->R2->R6->R7->R4->R9) New Path (ERO = R1->R2->R3->R4->R9) - shared with Current Path Until R9 gets new Path Message, current Resv is refreshed Pop 22 49 17 R8 R2 R6 R3 R4 R7 R1 R5 R9 32

79. 78 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Non-Disruptive Rerouting - Switching Paths Pop 22 38 49 17 R8 R2 R6 R3 R4 R7 R1 R5 R9 32 Resv: allocates labels for both paths Reserves bandwidth once per link PathTear can then be sent to remove old path (and release resources) 89 26

80. 79 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Reroute - More Details R2 R3 R1 R2-1, R3-1 00 ERO (R2-1, R3-1) Sender_Template(R1-lo0, 00) 2 3 1 3 1 2 Session(R3-lo0, 0, R1-lo0) R2-1, …, R3-3 01 ERO (R2-1, …, R3-3) Sender_Template(R1-lo0, 01) 00 01 Resource Sharing

81. 80 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Reroute - More Details R2 R3 R1 Path: Common_Header Session(R3-lo0, 0, R1-lo0) PHOP(R1-2) Label_Request(IP) ERO (R2-1, …,R3-3) Session_Attribute (S(3), H(3), 0x04) Sender_Template(R1-lo0, 01) Sender_Tspec(3Mbps) Record_Route(R1-2) 2 3 1 3 1 2

82. 81 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Reroute - More Details R2 R3 R1 23 1 3 Path State: Session(R3-lo0, 0, R1-lo0) PHOP(R1-2) Label_Request(IP) ERO (R2-1, …,R3-3) Session_Attribute (S(3), H(3), 0x04) Sender_Template(R1-lo0, 01) Sender_Tspec(3Mbps) Record_Route (R1-2)

83. 82 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Reroute - More Details R2 R3 R1 23 1 3

84. 83 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Reroute - More Details R2 R3 R1 23 1 3 RSVP: Common_Header Session(R3-lo0, 0, R1-lo0) PHOP(R3-3) Style=SE FlowSpec(3Mbps) Sender_Template(R1-lo0, 01) Label=POP Record_Route(R3-3)

85. 84 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Reroute - More Details R2 R3 R1 23 1 3

86. 85 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Reroute - More Details R2 R3 R1 23 1 3 RSVP: Common_Header Session(R3-lo0, 0, R1-lo0) PHOP(R2-1) Style=SE FlowSpec (3Mbps) Sender_Template(R1-lo0, 01) Label=6 Record_Route(R2-1, …, R3-3) Sender_Template(R1-lo0, 00) Label=5 Record_Route(R2-1, R3-1)

87. 86 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Reroute - More Details R2 R3 R1 23 1 3 RSVP state: Session(R3-lo0, 0, R1-lo0) PHOP(R2-1) Style=SE FlowSpec Sender_Template(R1-lo0, 01) Label=6 Record_Route(R2-1, …, R3-3) Sender_Template(R1-lo0, 00) Label=5 Record_Route(R2-1, R3-1)

88. 87 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Fast Restoration Handling link failures - two complementary mechanisms: Path protection Link/Node protection

89. 88 © 1999, Cisco Systems, Inc. Mosaddaq Turabi Assigning Traffic to Paths (aka autoroute) 88 © 1999, Cisco Systems, Inc.

90. 89 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Enhancement to SPF During SPF, each new node found is moved from a TENTative list to PATHS list. Now the first-hop is being determined via: A. Check if there is any TE tunnel terminating at this node from the current router and, if so, do the metric check B. If there is no TE tunnel and the node is directly connected, use the first-hop from adj database C. In none of the above applies, the first-hop is copied from the parent of this new node

91. 90 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Enhancement to SPF - Metric Check Tunnel metric: A. Relative +/- X B. Absolute Y C.Fixed Z The default is relative metric of 0 Example: Metric of native IP path to the found node = 50 1. Tunnel with relative metric of -10 => 40 2. Tunnel with relative metric of +10 => 60 3. Tunnel with absolute metric of 10 => 10

92. 91 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Enhancement to SPF - Metric Check If the metric of the found TE tunnel at this node is higher then the metric for other tunnels or native IGP path, this tunnel is not installed as next-hop If the metric of the found TE tunnel is equal to other TE tunnels, the tunnel is added to the existing next- hops If the metric of the found TE tunnel is lower than the metric of other TE tunnels or native IGP, the tunnel replaces them as the only next-hop

93. 92 © 1999, Cisco Systems, Inc. Mosaddaq Turabi Configuration 92 © 1999, Cisco Systems, Inc.

94. 93 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Enabling a Device for MPLS-TE Router(config)# mpls traffic-eng tunnels

95. 94 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Enabling MPLS-TE On Physical Interfaces Router(config-if)# mpls traffic-eng tunnels Router(config-if)# ip rsvp bandwidth

96. 95 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. MPLS-TE Configuration for OSPF Router(config)# router ospf Router(config-router)# mpls traffic-eng area Router(config-router)# mpls traffic-eng router-id loopback0

97. 96 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. MPLS-TE Configuration For IS-IS Router(config)# router isis Router(config-router)# mpls traffic-eng level Router(config-router)# mpls traffic-eng router-id loopback0 Router(config-router)# metric-style wide

98. 97 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. Configuring TE Tunnel On The Headend Router(config)# interface tunnel1 Router(config-if)# tunnel destination A.B.C.D Router(config-if)# tunnel mode mpls traffic-eng Router(config-if)# tunnel mpls traffic-eng bandwidth Router(config-if)# tunnel mpls traffic-eng affinity mask Router(config-if)# tunnel mpls traffic-eng autoroute announce Router(config-if)# tunnel mpls traffic-eng autoroute metric rel/abs... Router(config-if)# tunnel mpls traffic-eng path-option 1 explicit name test Router(config-if)# tunnel mpls traffic-eng path-option 2 dynamic

99. 98 © 1999, Cisco Systems, Inc. Mosaddaq Turabi Summary 98 © 1999, Cisco Systems, Inc.

100. 99 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. MPLS TE Benefits Provides traffic engineering capabilities at Layer 3 – above and beyond of what is provided with ATM (e.g. load-sharing on unequal cost paths)

101. 100 MPLS BOOTCAMP ( Mosaddaq Turabi) © 2000, Cisco Systems, Inc. References RFC 2702: Requirements for Traffic Engineering Over MPLS Extensions to RSVP for LSP Tunnels –draft-ietf-mpls-rsvp-lsp-tunnel-03.txt Applicability Statement for Extensions to RSVP for LSP-Tunnels – draft-awduche-mpls-rsvp-tunnel-applicability-01.txt RFC2430 IGP Requirements for Traffic Engineering with MPLS – draft-li-mpls-igp-te-00.txt RFC2370: The OSPF Opaque LSA Option Traffic Engineering Extensions to OSPF – draft-katz-yeung-ospf-traffic-01.txt IS-IS extensions for Traffic Engineering – draft-ietf-isis-traffic-01.txt Calculating IGP routes over Traffic Engineering tunnels – draft-hsmit-mpls-igp-spf-00.txt

102. 101 Presentation_ID © 1999, Cisco Systems, Inc.