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NOBEL WP2 Meeting

NOBEL WP2 Meeting. TID Contributions A2.1: Resiliency in multi-layer networks Advance Resilience Study Group Madrid, 11-13.03.05. A2.1: AR - SG. TID contributions to A2.1 are concentrated in the Advance Resilience Study Group (AR-SG), where TID is working on the following topics:

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NOBEL WP2 Meeting

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  1. NOBEL WP2 Meeting TID Contributions A2.1: Resiliency in multi-layer networks Advance Resilience Study Group Madrid, 11-13.03.05 NOBEL WP2 April 1

  2. A2.1: AR - SG • TID contributions to A2.1 are concentrated in the Advance Resilience Study Group (AR-SG), where TID is working on the following topics: • MPLS Fast Reroute • MultiPath Resilience schemes: • MRDV in IP layer • MRDV for OBS NOBEL WP2 April 2

  3. A2.1: AR – SGBrief Description of MPLS FRR features • MPLS Fast Reroute is a set of local protection techniques used to reroute the traffic flows through a previously established backup path while the rerouting process takes place. • Typical performance times are around 50ms, enough to maintain a QoS and provide real time applications. • MPLS FRR mechanisms can be used with RSVP-TE or LDP. • Currently, Fast Reroute mechanisms are implemented differently by the diverse vendors because its standardization has not been completed yet. NOBEL WP2 April 3

  4. A2.1: AR – SGFRR using RSVP-TE • Using RSVP-TE without Fast Reroute, LSPs are protected but the backup path is calculated and rerouted from the ingress node. • With Fast Reroute, we redirect data flow through an alternative backup path with the required QoS characteristics from the Point of Local Repair (PLR). • Several techniques: One to one backup and Facility backup (node and link protection). • To provide Facility backup, a LSP is created to be used as a backup for a set of LSPs (Tunnel Bypass) : • Next-Hop bypass LSP: a LSP between neighbours is created. • Next-Next Hop bypass LSP: a LSP is created to avoid a particular node in the path. NOBEL WP2 April 4

  5. A2.1: AR – SGFRR using RSVP-TE. Examples Link protection with Facility backup. Node protection with Facility backup. One to one backup. The tunnel bypass protects the three protected LSPs at the same time. NOBEL WP2 April 5

  6. A2.1: AR – SGFRR using LDP • Using LDP without Fast Reroute, in case of a node/link failure the time of IP convergence is too long to provide real time applications. • With Fast Reroute, we add mechanism to the MPLS network to avoid loops and packet loss until the backup LSP is established. • Several techniques: Loop-free alternate, U-turn alternate and Explicit Routing. • Loop-free and U-turn mechanisms proceed as: • Pre-calculating the path to prevent failures with the previous SPF calculus. • This path is used when a failure occurs in the local link. • Meanwhile, the node calculates a new SPF based on the new modified topology and installs it in the plane. • Once the path is established, the traffic is sent over it. NOBEL WP2 April 6

  7. A2.1: AR – SGFRR using LDP. Example of loop-free Data loops are created until new routes are calculated and IP converges. With Fast Reroute, the traffic is routed through a loop-free neighbor to reach the egress node avoiding loops. NOBEL WP2 April 7

  8. A2.1: AR – SGFRR using LDP. Example of U-turn No loop-free alternate path from LSR3 to LSR1 due to the network topology. With Fast Reroute, the traffic is routed through a U-turn neighbor breaking the loop and reaching the egress node. NOBEL WP2 April 8

  9. A2.1: AR – SGFRR: Future milestones • Evaluation of the different mechanisms under study in order to establish which scenarios fit better to provide higher performances. • Analysis of the convenience to use MPLS Fast Reroute with RSVP-TE or LDP in different scenarios. • Software simulations with typical current network configurations to extract some useful parameters in order to study the different solutions given by the vendors. • Timing performance analysis to ensure the QoS requirements of real time applications. NOBEL WP2 April 9

  10. A2.1: AR – SGMultiPath Resilience Scheme • TID will evaluate MultiPath Resilience Mechanisms based on the MRDV algorithm in both IP and optical layers • Assumptions: • Reference Network • E.g: LION Core reference network and/or Madrid Metro Network • Availability Model • Availability numbers included in the “availability model and OPEX related parameters” • Simulation Scenarios • Only UDP traffic • TCP and UDP traffic NOBEL WP2 April 10

  11. A2.1: AR – SGMultiPath Resilience Scheme in IP networks • TID will simulate MRDV routing algorithm considering the previous assumptions and will compare the obtained results with those obtained by using ECMP • The benefits of using MRDV when failures occur will be evaluated by considering the following scenarios and parameters: • UDP scenario: • Packet loss ratio • Mean Delay • Jitter • TCP/UDP scenario: • Throughput • Mean Delay • Maximum Delay NOBEL WP2 April 11

  12. A2.1: AR – SGMultiPath Resilience Scheme in optical networks • TID will update the MRDV routing algorithm to be used over OBS networks considering different link metrics • Blocking probability • Load • Furthermore, TID will evaluate the benefits of using MRDV when failures occur in OBS networks by: • Simulating its behavior considering the previous assumptions • Comparing its results with other schemes NOBEL WP2 April 12

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