LDP Extensions for Optimized MAC Address Withdrawal in H-VPLS draft-pdutta-l2vpn-vpls-ldp-mac-opt-01.txt

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LDP Extensions for Optimized MAC Address
Withdrawal in H-VPLSdraft-pdutta-l2vpn-vpls-ldp-
mac-opt-01.txt
Pranjal Kumar Dutta Marc Lasserre
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H-VPLS MAC Withdrawal

• Mechanism to unlearn MAC addresses that have been
  dynamically learned in a VSI for faster
  convergence on topology change
• Null MAC withdrawal (LDP address withdraw with
  empty MAC address list)
• Main mode
• Unlearn all MACs except the ones over which the
  message is received
• Specified list of MACs to withdraw

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Problem Statement

• Blind Null MAC Address Flushing
• The MAC addresses removed in this procedure also
  include the MAC addresses learned from LDP
  sessions in the same VSI that are not actually
  affected due to such topology change

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Solution

• Extension to LDP Address Withdraw Message with
  empty MAC List
• To enable PEs receiving the message to remove
  only the MAC addresses that are affected and need
  to be relearned
• Use of optional LSR-ID TLV in LDP Address
  Withdraw Message
• E.g. 32-bit router-id

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Benefits

• Faster Convergence
• Fewer MACs need to be relearned
• When a PE-rs receives a NULL MAC address withdraw
  message with the LSR-ID TLV option, it SHOULD
  flush all MACs learned from the PW over LDP
  signaling session with the PE identified by
  LSR-ID Element

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Next steps

• Solicit comments on L2VPN list