L2 Port-channel/L3 SVI across MAN link detection

[fhoban]

Hi, I have come across 2 x sites that connect via L2 port-channel with a layer 3 SVI on each end for routing ; protocol is OSPF. Cat4k on customer side with a 37xx switch stack DC side. These links are from the same provider [ 2 x 100Mbps MAN ]. Problem is the end to end loss/detection. If switch port is down on one side then other side cannot detect so traffic will get blackholed as it continues to go down the both links. What would be the best solution here ? Probably BFD on port-channel but you may need it on a per link basis [micro-bfd] but this I guess is not supported on these platforms ; otherwise it will function like any ip flow and get polarized to one of links.

Thanks in advance.

[balaji.bandi]

How about IP SLA ? do you consider ?

BB

[fhoban]

Dont think IPSLA is any good in this case. it's L3 so even if 1 link is up the sla will be OK. Main issue is the L2 port-channel and Carrier equipment.

Thanks

[chrihussey]

Probably not the answer you want, but it may be best to have two 100Mb links, OSPF peer across both, have them equal cost paths and let load sharing take over. This puts the control in your hands and not have to rely on the provider. To me that's always preferred.

Regards

[fhoban]

You are right and it would be the preferred way for sure. I guess if LACP functioned properly as well it would work ok too.

Thanks!