Question 790
An EVPN multihoming service uses per-ES designated forwarding behavior. Observed: A newly connected PE advertises the service but never forwards BUM frames when elected. What evidence would validate recovery from this precise failure mode?
Explanation
Correct Answer
The intended result is Each VLAN has the expected DF and BUM traffic follows one permitted path. It specifically verifies recovery from the pe's df election view disagrees because vlan or ethernet tag association is inconsistent, which produced the original symptom: A newly connected PE advertises the service but never forwards BUM frames when elected. It is stronger evidence than a generic interface-up indicator.
Incorrect Answers
This result is useful in another case with evidence One remote PE receives BGP routes but does not establish the required connection. It does not test recovery from a newly connected pe advertises the service but never forwards bum frames when elected. Check instead whether each VLAN has the expected DF and BUM traffic follows one permitted path.
It confirms an unrelated service correction: Ethernet segment split-horizon or designated-forwarder behavior is incorrect. The present case reports A newly connected PE advertises the service but never forwards BUM frames when elected. Its completion test is Each VLAN has the expected DF and BUM traffic follows one permitted path.
That observation would verify a separate fault involving l2vpn rt filters permit cross-service membership despite separate service definitions. Its symptom is A transit PE imports endpoints from an unrelated L2VPN. For this case the actual issue is the pe's df election view disagrees because vlan or ethernet tag association is inconsistent, and the relevant success signal is Each VLAN has the expected DF and BUM traffic follows one permitted path.