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This update proposes enhanced 1:N protection mechanisms for UNI and E-NNI scenarios, ensuring local signaling and no end-to-end requirements. It includes deferred requirements and introduces new concepts for interface protection.
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Update for 1:N Protection capability Control Plane assisted 1:N link connection protection
Content • Updated and revised requirements • Deferred some requirements • Generic description of applicability of 1xN protection mechanisms for UNI and E-NNI scenarios • Proposal Use Cases are available in oif2006.130
1:N Link ProtectionRequirements phase 1 • 1:N signaling must be kept local to the interface • Must not require end-to-end signaling or that the remote endpoint of connection supports UNI • E-NNI 1:N implementation should be independent on whether the call was established as SC or SPC • Must be able to support channelized and non-channelized interfaces • Protect connections using a higher bandwidth channelized interface • Misconnection must not occur during protection switching • Client Device must not send traffic onto protection interface until physical layer connectivity is complete (indicated via receipt of ack) • Must support reversion • Need to ensure adequate differentiation between switchover and restart messages to ensure proper handling of all failure scenarios. There must be absolutely no potential for confusion within a network element getting confused between modify and restart
1:N Link ProtectionDeferred Requirements • UNI 1:N should include support for SPCs (if UNI-C and UNI-N are present and a communication channel exists between them) • Must be able to support channelized and non-channelized interfaces • Protect only some connections from within a channelized interface • Protect connections using a higher bandwidth channelized interface • A single signaling message should be capable of carrying protection information about multiple connections • E.g., particularly relevant for channelized interfaces
1:N Protection UNI ApplicationLocal Span Protection Client N working interfaces Protection interface Transport NE Client NE (e.g., IP router) • Protects against failure: software failures on the client router port, client interfaces, link interconnecting client and transport NE, transport NE line card failure • No re-routing or connection set-up required • Enabled by capabilities on client, transport NE – switching at transport NE and re-routing traffic within client from failed interface to protection interface
Feasibility: IP Routers • 1:N interface new concept for IP, exists for transport • Layer 1 switching • Signaling between router and transport • Layer 2 resynchronization • Avoid or optimize • Layer 3 re-routing (complexity is in the router) • Switch to different interface • Copy interface-specific state to protection interface(including TNA/Interface Id information) • Avoid routing protocol updates • 1:N interface protection achievable • Demonstrated in AT&T Research Labs using non-commercial prototype routers and AT&T developed signaling extensions • POS, GbE interfaces • Sub-second recovery times (approx. 50msec in simple experiments) • REF: P. Sebos, et al., “Ultra-fast IP link and interface provisioning with applications to IP restoration,” to appear at OFC 2003, available after OFC (March 2003) at http://www.research.att.com/areas/opticalnetworking/IPoverWDMpublications.html
1:N Protection E-NNI ApplicationInter-carrier mid-span meet SCN XC XC Patch panel Patch panel
1:N Protection E-NNI Application Intra-carrier inter-continental SCN XC XC POI Patch panel POI Patch panel
Proposal • Include 1xN protection capability in UNI 2.0 and E-NNI 2.0 Signaling • Liaise requirements and signaling proposal to ietf/ccamp for feedback