UDLD Behaviour

[lukas.krisak]

Hello guys,

At this time I can't check UDLD behaviour on real devices so I would like to ask here at least.

If you have both sides configured with UDLD aggresive, link is bidirectional and running.

What happens if you reload one switch? Will the other one's interface go UDLD disabled (as it will no more hear any UDLD echo back) or will it go just down/down.

Thank you for your answer.

[Peter Paluch]

Hi Lukas,

Sorry for replying lately. I am not completely sure myself but I believe that when you reload a switch, it will cause interface flap (up->down transition). The neighboring switch whose port is UDLD-protected will also go down, and the UDLD negotiation will start from scratch after the link becomes operational again.

I will have to confirm this in my lab, though.

Best regards,

Peter