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Status message

Some aspects to be determined in PIRC July 2007 802.17 Plenary Meeting San Francisco, U.S. yanw@huawei.com Huawei Technologies. Status message.

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Status message

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  1. Some aspects to be determined in PIRCJuly 2007 802.17 Plenary Meeting San Francisco, U.S.yanw@huawei.comHuawei Technologies IEEE 802.17 RPRWG

  2. Status message • Status message is respectively transmitted periodically by two inter-ring nodes of a protection group to notify the status the to opposite inter-ring node. • Only inter-ring nodes process the status message • New controlType • Broadcast address or new multicast address • Appropriate transmission interval IEEE 802.17 RPRWG

  3. Status message function • Status message notifies the local inter-ring node’s status to the opposite inter-ring node. • Active: Notify status change of the local inter-ring node to the opposite inter-ring node • When the inter-ring node can’t forward traffic because forwarding function failed or one ring function failed. • When the failed inter-ring node recovers. • Passive: When no status messages from opposite inter-ring node are received • Through two rings: the opposite node is down. • Through one ring: one ring function of the opposite node is down. IEEE 802.17 RPRWG

  4. controlDataUnit of the status message • Status message could include the following information, • Protection group ID • Forwarding status (None, Traffic set 1, Traffic set 2, Both) • Traffic can be classified by VLAN ID, MAC address and/or other information. • The inter-ring node may forward none, one, or both parts of the traffic. • Under normal status, the forwarding status is decided by configuration or negotiation. • Under protection status, the forwarding status is decided by the protection mechanism. • To TTL balancing method, this field may be not needed. IEEE 802.17 RPRWG

  5. controlDataUnit of the status message (cont’) • Failure indication (No Failure, Partial failure, inter-ring forwarding failure) : Indicate the inter-ring node’s forwarding function failure, one ring function failure and the failure’s recovery. • Configuration information (Priority, DevID etc.): May be used to negotiate the forwarding status during initialization or during the running time dynamically. • Any others? IEEE 802.17 RPRWG

  6. Back-to-back interconnected PIRC rings • The status of the two back-to-back nodes should be synchronized. • The message is needed to notify the status between two back-to-back nodes. This message is not a RPR message. • Should new message and new mechanism be defined for this scenario? IEEE 802.17 RPRWG

  7. Multiple links failure protection • Multiple links failure can be detected by • Status message • One inter-ring node can’t receive the status message from the opposite node through one ring. • But no inter-ring node failure notification is received through the other ring. This can be used to differentiate with one ring RPR function failure. • TP message • In order to protect the inter-ring traffic, both inter-ring nodes should be in forwarding status. IEEE 802.17 RPRWG

  8. Transient Loop in PIRC • The possibility of two inter-ring node forwarding when one inter-ring node recovers from failure. • For multiple links failure protection, both inter-ring nodes are in forwarding status. After link defect disappears, there will be transient loop. • In relax mode, transient loop could be tolerated. • In strict mode, transient loop should be avoided. IEEE 802.17 RPRWG

  9. Strict mode for loop prevention • In a protection group, anytime only one inter-ring node forwards traffic between the rings. • Don’t support multiple links failure protection. • Guarantee two inter-ring nodes not in forwarding status at the same time. • When one inter-ring node switch into forwarding status, it should make sure that the other one is not in the forwarding status. • Sometime failed inter-ring node should take action and/or notify the other inter-ring node IEEE 802.17 RPRWG

  10. Strict mode for loop prevention (cont’) • Modify the node’s recovery mechanism • When inter-ring node recovers, it shouldn’t switch into forwarding status immediately. • When nodes adjacent to the failed link find the link recovers, they shouldn’t switch to normal status immediately. • Timer mechanism • They keep in protected status until their timers expire. • Before the timers expire, the correlative interconnected node shall know the reversion and stop forwarding. • Notification mechanism • They keep in protected status until the correlative interconnected node stops forwarding and notifies them. IEEE 802.17 RPRWG

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