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MAC Withdraw Signaling for static PW draft-boutros-l2vpn-mac-wd-03.txt

MAC Withdraw Signaling for static PW draft-boutros-l2vpn-mac-wd-03.txt. Himanshu Shah - Ciena Siva Sivabalan , Sami Boutros – Cisco Sam Aldrin - Huwei. Brief History. This draft was first introduced in 2011 Service Providers requesting this feature

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MAC Withdraw Signaling for static PW draft-boutros-l2vpn-mac-wd-03.txt

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  1. MAC Withdraw Signaling for static PWdraft-boutros-l2vpn-mac-wd-03.txt Himanshu Shah - Ciena Siva Sivabalan, Sami Boutros – Cisco Sam Aldrin - Huwei

  2. Brief History • This draft was first introduced in 2011 • Service Providers requesting this feature • Presented details in IETF-88 and was well received • Added a new author • Sam Aldrin - Huweii

  3. Solution Overview • MAC withdraw signaling for dynamic PW is described in RFC 4762. It mitigates black holing of the traffic when dual-homed MTU-s switches over to standby PW • RFC 6478 describes PW status exchange in-band over the OAM channel with acknowledgements from the receiver. The draft uses the similar mechanisms for MAC withdraw signaling.

  4. MAC Withdraw signal • Sent over OAM channel with sequence number and MAC list TLV as defined in RFC 4762. • Receiving PE sets the ACK bit in the response • In absence of ACK, sender retries 3 times at one second interval • An ACK receipt with higher sequence is implicit ACK for all lower sequence sends • MAC List Optimization is supported as per http://tools.ietf.org/html/draft-ietf-l2vpn-vpls-ldp-mac-opt-08

  5. PE-1 PE-2 PE-3 PE-4 PE-5 PE-6 MAC Withdraw signaling – use case M T U Static PW Primary spoke PW Standby spoke PW Mesh PW MAC withdraw signal

  6. Reset Sequence Number • The version 03 added logic to signal resetting of the sequence number • A reset bit is defined in the MAC WD signal • Needed when a static PW is reset by way of node restart or other configuration changes • Local node notifies peer to reset send and expected receive sequence number • This mechanism prevents peer to ignore lowered sequence number MAC WD message from the reset’dnode

  7. Reset logic Node A Node B MAC WD, Seq# 1 Exprecvseq# 2 MAC WD ACK Seq# 1 MAC WD, Seq# 10 Exprecvseq# 11 MAC WD ACK Seq# 10 Static PW Reset MAC WD, Seq# 1 Ignore!!!! Less than expected 11 Solution MAC WD, Seq# 1, R-Bit Set Reset send & receive seq# Exprecvseq# 2 MAC WD ACK Seq# 1, R-bit set

  8. Use case • MPLS-TP deployments are taking hold in access networks • Static provisioning for PWs dovetails to static LSPs • This necessitates need for PW status (already an RFC) as well as MAC withdraw signaling for H-VPLS deployments with dual-homing

  9. Summary • Request to adopt as WG document • Reserve ACH channel type 0x28 • Comments?

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