Towards par for Segment Protection Switching m vinod Kumar



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Towards PAR for Segment Protection Switching

  • M Vinod Kumar

  • Abhay Karandikar


Agenda

  • Refresh

  • Motivation

  • Gaps in Present Standard

  • Terminology for Segment Protection- agreed so far

  • Summary of Segment Protection Requirements

  • Summary of Segment Protection Solutions discussed so far in the group

  • Pros and Cons of various solutions

  • Need for a PAR



Prior Arts

  • Eilat (May Interim) - Abhay presents SPS as means to solve P2MP protection

      • ay-Abhay-Protection-Switching-for-P2MP-0508.ppt
  • Denver (July Plenary) – Jointly by Abhay, Bob and John

      • new-sultan-fast-reroute-te-0708-v02.pdf
  • Seoul (Sept Interim) - Bob presents interpretations and observations, Dave presents issues to address and Vinod presents case for SPS

      • new-sultan-segment-protection-scaling-0908-v01.pps
      • new-martin-PBB-TE-segment-prot-0908-v01.pdf
      • new-Protection-Vinod-Case-for-Segment-Protection-0908-v1.pps
  • Dallas (Nov Plenary) -Vinod uploads document on case for SPS and No new work prez due to Lack of time

      • new-Vinod-SegmentProtectionSwitching-1108-v01.doc
      • new-martin-PBB-TE-segment-prot-1108-v00.pdf
      • new-sultan-segment-protection-requirements-1108-v02.pdf
  • New Orleans (Jan Interim) – Dave presents client-server method, Wei presents 3-tupple translation, Bob presents segment protection for infrastructure, and Vinod presents four distinct methods

      • new-martin-PBB-TE-segment-prot-0109-v00.pdf
      • new-weiyh-segment-protection-0109-v00.pdf
      • new-sultan-segment-protection-technical-proposal-0109-v01.pdf
      • new-vinod-SPS-modeling-0109-v1.ppt


Motivation

  • Reference:

    • new-Protection-Vinod-Case-for-Segment-Protection-0908-v1.pps
  • Carrier Requirements:

    • Infrastructure failure- major cause of outage
    • Service providers have the knowledge that certain links are more prone to failure
      • Upcoming areas/floods/road construction
    • Protection models must include N:1


Gaps in Present Standard

  • PBB-TE has addressed end-to-end protection of P2P TESI within a single domain.

  • Service providers need efficient mechanism to protect vulnerable links of the topology

  • N:1 is not addressed in PBB-TE.



Definitions of Segment

  • A Segment is a single link, or a sequence of links and bridges, providing connectivity between two bridges. The segment is bounded at each end by a Provider Network Port (PNP). A bridge lying within the segment is a BCB. A segment endpoint bridge is a BCB or an IB-BEB.

  • A Primary segment is a segment along whose path one or more TESIs have been coincidently provisioned

  • A Backup segment is a segment having the same endpoint bridges as the primary segment but whose path is otherwise disjoint from the primary segment.

  • An Infrastructure Segment is Sequence of links and bridges that protects atleast one TESI coincident with it

  • A Data Path Segment is portion of a TESI bounded by a PNP at each end

    • Multiple Data Path segments can be associated with an infrastructure segment
  • Infrastructure Protection - Preserve connectivity of all TESIs transiting an active infrastructure segment on the failure of one or more links or bridges associated with that segment.

  • Data Path Protection - Preserve connectivity of a TESI in the presence of a TESI data path failure occurring within the active TESI segment due to link failure, node failure, FDB corruption, etc.

  • M:1 Protection – Support multiple backup segments (M≥1) to which traffic can be switched in the event of the failure of the primary segment. The backup segment having the highest provisioned priority value among operational backup segments is selected to be the active segment. Should support Load Balancing. M = 3 atleast.



Types of Segment Protection Schemes

  • Infrastructure Segment Protection

  • Data Path Segment Protection

  • There is an agreement on the requirements for Infrastructure Segment Protection



Infrastructure Segment Protection Requirements

  • new-sultan-segment-protection-requirements-0109-v01.pdf

  • new-irene-Segment-Protection-Requirements-0309-v01.ppt

  • Maintain the same or better quality of transport as offered by PBB-TE

  • End-to-end integrity must be honored

  • Solution must be operationally simple and should not require large number of provisioning action

  • Solution shall not switch traffic when there is no fault unless required by management commands

  • Shall have minimal impact on bridge architecture

  • Shall support N:1 protection group with load sharing support

  • Address the relatively high failure rate of particular links or bridges within a network.

  • Address the likelihood of concurrent failures occurring in different segments of a network.

  • Allow maintenance activities to be performed independently in different segments of the network.

  • Provide an efficient means of protecting portions of a PtMP TESI.



Segment Protection Solutions

  • Segment Protection Solutions can be broadly classified in three types:

    • Hierarchical (Client server by Dave, Triple Q by Vinod Tejas)
    • Cascaded (Tuple switch by Wei ZTE, BB-BEB model by Vinod)
    • Port redirection by Bob


Hierarchical Segment Protection

  • This is also known as Client-Server model (Dave) or Triple MAC (Vinod)

  • Upgrade the BCBs at the edges of the segment to IB-BEBs and provide a PBB hierarchal (802.1ah 26.6.1) S-tagged interface (802.1ah 25.4)��

  • Each segment is now a new (server layer ) TESI in a regular PBB-TE 1:1 TESI PG, with the corresponding TESI CCM integrity coverage



Cascaded Segment Protection

  • Also known as 3-tupple translation (Wei Yuehua) or Enhanced BB-BEB (Vinod)



Overlay Segment Protection

  • Also known as port-redirect (Bob Sultan)

  • Only addresses Infrastructure Segment Protection Switching

  • Special logic needed at AIB and PIB to correlate the faults and port-redirect or switch the TESI without forwarding ambiguity





PAR



What do we get?

  • Protection segments are pre-provisioned to allow sub-50ms protection switching

  • The segments forming protection group are constantly monitored

  • Optimal network resource utilization

    • By protecting portion of e2e TESI
    • By supporting load sharing with N:1
    • By supporting minimal provisioning for protection


Value Proposition

  • Segment Protection has same economic feasibility as that of Backbone Edge Bridges

  • The protection mechanism is applicable to any topology

  • Improves network utilization by not performing e2e protection whenever possible

  • Reduces provisioning complexity of e2e protection mechanism by protecting portion of e2e transport

  • Enables protection of critical portion of a packet transport

  • Enables efficient protection of branches of P2MP



OAM requirements

  • OAM shall reuse PBB-TE OAM components

  • No need to use unreliable control plane



What would IEEE specify

  • Amendment to Qay

    • Amend .1ag


Title

  • IEEE standard for Local and Metropolitan Area Networks --- Virtual Bridged Local Area Networks --- Amendment ?? --- Transport Segment Protection Switching



Scope: What project is

  • The scope of this project is to define feature extension of 802.1Q (2005) supporting protection of critical portion of the provisioned or traffic engineered services by offering at-least the same guarantee as offered originally by the traffic engineered services with minimal impact on existing standards



Scope: What Project is not

  • The project will only provide features necessary to support external management plane command or control plane.

  • The selection of protection segment and bandwidth management either through management commands or by control plane is outside the scope of this project



Scope: Required Features

  • The features specified in this project enhance, support and rely on the PBB (IEEE 802.1ah), PBB-TE (IEEE 802.1Qay), and CFM (IEEE-802.1ag) standards. In doing so, it shall:

    • Maintain the same or better quality of transport as offered by PBB-TE
    • End-to-end integrity must be honored
    • Solution must be operationally simple and should not require large number of provisioning action
    • Solution shall not switch traffic when there is no fault unless required by management commands
    • Shall have minimal impact on bridge architecture
    • Shall support N:1 protection group with load sharing support
    • Address the relatively high failure rate of particular links or bridges within a network.
    • Address the likelihood of concurrent failures occurring in different segments of a network.
    • Allow maintenance activities to be performed independently in different segments of the network.
    • Provide an efficient means of protecting portions of a PtMP TESI.


Purpose

  • An important objective of provisioned packet transport is to efficiently protection switch the traffic

    • Use less network resources
    • Sub-50 ms resiliency
    • Build on existing standard building blocks
    • Provide aggregate protection of all TESI
  • This project will amend the .1Q standard



Need for Project

  • Currently there is no mechanism to manage portion of a (provisioned) packet transport that is liable to fail more often than other portion of the packet transport

  • The project will address OAMP and protection switching of critical portion of the end-to-end packet transport and support N:1 load sharing



Stakeholders

  • Developers and users of networking for Provider network environments including networking IC developers, switch and NIC vendors, and users.



Thank-you





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