Hello sreenath@akn.co.in ,
the basis of IP Fast ReRoute FRR is BFD = Bidirectional Forwarding Detection.
BFD is a very simple protocol that can be used between directly connected routers or multilayer devices to speed the detection of faults . Here the key is directly connected at OSI layer 3.
If two routers are connected using a switch in the middle when R2 interface fails R1 interface stays up and R1 will detect R2 failure when an appropriate timer ( OSPF dead interval or EIGRP hold time ) expires.
Insted of using very frequent hello messages in OSPF or other protocols that are rather complex to create and process BFD creates a simple keepalive mechanism.
The routing protocols become "clients" of the BFD session and their state will become dependent on the state of BFD.
BFD simplicity allows on distributed platforms like an ASR 9000 to perform the BFD processing on the linecards offloading the central CPU of the route processor from this duty.
So you can use the feature navigator and look for BFD support.
Note: IP FRR is not limited to BFD support but as a first sight on the matter it gives you the basic idea.
Hope to help
Giuseppe
