Does FabricPath relies only on IS-IS hello exchange to detect link failures or does it implement BFD (Bidirectional Forwarding Detection)?

[doctor_1602]

I'm trying to understand if FabricPath relies only on IS-IS hello exchange to detect link failures or if it implements BFD (Bidirectional Forwarding Detection) to reduce the failure detection time. I noticed n RFC to introduce BFD in TRILL signed by a person from Cisco, so I was wondering if they adopted that in FP.

Thanks.

[Jerry Ye · Accepted solution]

FP uses IS-IS hello to detect link failures. In a DC environment, P2P link is used to interconect FP and FP IS-IS will react to port down notification.

HTH,

jerry

[doctor_1602]

So.. it doesn't wait for a certain time after which if no hellos are received the link is considered down. It react as soon as a port down notification is received... right?
So what if aggregated links are used? How does it behave?

[Jerry Ye]

If it is inside the same DC with P2P link, yes. FP will react when it detects port down.

I am assuming aggregated links means DWDM to another DC. If this is what you mean, then it will rely on the IS-IS hello timer.

[doctor_1602]

I was wondering about a Link Aggregation Group or what Cisco refers to as EtherChannel. I guess it is possible to use these links between switches... right?

[Jerry Ye]

Yes, EtherChannel/Port-Channel is preferred to connect between FP nodes, and Port-Channel will behave the same link the individual link (it is P2P).

[doctor_1602]

Thanks a lot!