BFD support on 3560CG and C3560CX switches

[nezz]

I have 6 sites with WS-C3560CG-8TC-S switches and one with the newer WS-C3560CX-8TC-S. We need to implement BFD on all of them to sort out our routing.

3560CG's are running ipbase 15.0(2)SE8

The 3560CX is running ipservices15.2(4)E2

I can issue all required BFD commands ok on the 3560CX but the 3560CG's won't accept any of them except for bfd all-interfaces under the ospf process section.

So, do I need to upgrade all the ipbase switches to ipservices, or do I just need to upgrade the IOS on the 3560CG switches to a newer version to support BFD? I have looked at the feature navigator but am none the wiser for it.

[Mark Malone]

Hi

Can you not just use the BFD all interface then turn it off on the interfaces you dont want it to be on ?

There are two methods for enabling BFD support for OSPF:

• You can enable BFD on all the interfaces for which OSPF is routing by using the bfd all-interfaces command in router configuration mode. You can disable BFD support on individual interfaces using the ip ospf bfd [ disable ] command in interface configuration mode.
• You can enable BFD on a subset of the interfaces for which OSPF is routing by using the ip ospf bfd command in interface configuration mode.

dont think its softwrae as below

Prerequisites for Bidirectional Forwarding Detection

Prerequisites for BFD include:

• The switch’s feature set is IP Base or higher. The IP Base feature set supports only EIGRP stub routing without BFD. The IP Services feature set supports EIGRP with BFD.
• IP routing must be enabled on all participating switches.
• One of the IP routing protocols supported by BFD must be configured on the switches before BFD is deployed. You should implement fast convergence for the routing protocol that you plan to use. See the IP routing documentation for your version of Cisco IOS software for information on configuring fast convergence. See the “Restrictions for Bidirectional Forwarding Detection” section for more information on BFD routing protocol support in Cisco IOS software.

[Joseph W. Doherty]

BFD support varies across Cisco platforms. Older platforms might not support at all.

Without research, unable to say whether your older equipment supports BFD.

If not, there are some other technical approaches that often can deliver BFD lost detection like performance that might be available. Also on LAN based L3 switches, what kind of routing do you need to "sort out" that needs BFD?

[nezz]

Hi, thank you for the responses.
 
I'm going to do some more work on this next week. The issue we have is that internet access at remote sites goes through ASA at the main site and it doesn't work when we failover from primary WAN to backup ipsec tunnel. I'm looking at using BFD to detect when the main WAN connection goes down so I can have 2 default routes on the L3 switch with different metrics. OSPF is only running on the main WAN circuit, backup connections are via ipsec tunnels (c887's at remote sites terminating at ASA5510 pair at the main site).
 
Normal operation: L3 switch gets default route from OSPF (interface on ASA at main site)
On primary WAN failure: L3 switch needs to have a new default route towards the C887 when main WAN fails.
 
I am trying to avoid using ipsla/tracking and was directed towards BFD. If there is another way then I'm all ears!

[Joseph W. Doherty]

You're saying OSPF stays up when main WAN goes down?

What were you going to apply BFD to?

[nezz]

No, if the main WAN fails at a remote site its L3 switch loses all OSPF routes.
If the main WAN fails and I have a static default route on the L3 switch (pointing towards the C887) site to site traffic switches to the backup tunnel and all is well. However, if this same route is present when the main WAN is up, internet traffic doesn't make it to the ASA at the main site as it gets routed to the local C887, site to site traffic is fine . As you would expect, the statically defined route on the switch is overriding the injected one we get from OSPF.

Maybe I can just fix it by adjusting default route metrics and forget about BFD altogether??

[nezz]

.........I should've said, maybe I can fix it by adjusting the static default route AD on the L3 switch to be >110 and forget about BFD altogether??