BFD is used in Router in which type of connectivity direct or indirect?

[ravisharmadce]

plz suggest

In what scenerio we use BFD either direct or indirect connectivity from router side?

[Bilal Nawaz]

I think your question is asking how to use BFD

BFD provides a low-overhead, short-duration method  of detecting failures in the forwarding path between two adjacent  routers, including the interfaces, data links, and forwarding planes.  BFD is a detection protocol that you enable at the interface and routing  protocol levels. Cisco supports the BFD asynchronous mode, which  depends on the sending of BFD control packets between two systems to  activate and maintain BFD neighbor sessions between routers. Therefore,  in order for a BFD session to be created, you must configure BFD on both  systems (or BFD peers).

Some scenario's are given in this link below.

http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/fs_bfd.html#wp1053447

Hope this helps

[Giuseppe Larosa]

Hello Ravi,

indirect connection via an OSI layer 2 LAN switch is the typical scenario where BFD is used. It solves the problem that in case of failure of the routing next-hop the local node interface is still up/up.

BFD packets are based on UDP so they are on OSI layer4 above layer3 so there is no dependency from the technology in use. So it can be used also on POS links for example.

But there are also other mechanisms like forms of OAM like Ethernet OAM or OAM in Sonet/SDH networks that can be used, but they are dependent on specific technology in use on the links.

Hope to help

Giuseppe