Does BFD work at Layer 2 for ISIS and OSPF?

[loris.marcellini]

Hey folks,

I read BFD work across bundled interfaces for ISIS, OSPF and static routing. Now considering that on bundled interfaces you can configure a vlan, does that mean BFD works for layer 2 for ISIS and OSPF? The configuration guide says that but I am not really sure if I am reading it right

https://www.cisco.com/c/en/us/td/docs/routers/crs/software/crs_r6-1/routing/configuration/guide/b-routing-cg-crs-61x/b-routing-cg-crs-61x_chapter_0100.html#ID643

[balaji.bandi]

Some explanation help you to make some clarity here : (hope this helps you)

https://www.cisco.com/en/US/technologies/tk648/tk365/tk381/technologies_white_paper0900aecd80243ff4.html

[loris.marcellini]

I read the paper and it seems the bottom line here is, BFD helps detect layer 2 failures but essentially just work enabled on upper layer protocols. Therefore I am assuming the answer to my question is no, despite ISIS and OSPF supporting BFD over bundled vlan links, that does not translate into BFD works on layer 2 for OSPF and ISIS. 

Am I making sense or completely missing the point here?

[balaji.bandi]

Personally BFD use-case most of the time layer3 only ( never seen myself works on Layer 2)

Layer 2 ( UDLD)

https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/10591-77.html

Layer 3 (BFD)

https://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/fs_bfd.html

Hope is make sense ?