VPLS/IPLS Full Mesh Failures

1
VPLS/IPLS Full Mesh Failures

• Assumption that full mesh of PWs is present.
• If assumption fails, black holes can occur.
• Failure modes
• Data plane failures that misdirect or drop
  packets
• Loss of proper PW state at edges
• Auto-discovery/configuration failures
• But remember PWs not real wires
• Implemented via any-any network
• Increase in error coverage is small
• Failures not caused by backhoes, router outages,
  but by bugs and errors.

2
Bad Ideas for Detecting Failure

• Local Information (detection only)
• mismatch between operational PWs and discovered
  endpoints
• PW operational status changes
• Global Information (with resilience)
• PWs as overlay network, run SPT
• PWs as overlay network, run routing

3
Not Quite So Bad Idea?

• Global Information (detection only)
• Each edge tells every other edge here are the PW
  endpoints I can talk to
• Get global info, from each edge, set of other
  edges that can be seen.
• Any edge not universally seen is removed from
  mesh.
• Is this worth pursuing?