Which statement about BFD on Cisco IOS XR Software is true?

The correct answer is C. Cisco IOS XR router must use dynamic routing or a static route back to the Cisco IOS router to. BFD (Bidirectional Forwarding Detection) requires bidirectional reachability between peers. When a Cisco IOS XR router needs to establish a BFD session with a Cisco IOS router, the IOS XR router must have a valid return path - either via a dynamic routing protocol or a…

Unicast Routing

Question

Options

ACisco IOS XR router must use LDP to route back to the Cisco IOS router to establish the peer
BCisco IOS XR Software does not support BFD multihop for IPv4.
CCisco IOS XR router must use dynamic routing or a static route back to the Cisco IOS router to
DBFD is not compatible between Cisco IOS XR and Cisco IOS Software.

How the community answered

(59 responses)

A
2% (1)
B
3% (2)
C
95% (56)

Explanation

BFD (Bidirectional Forwarding Detection) requires bidirectional reachability between peers. When a Cisco IOS XR router needs to establish a BFD session with a Cisco IOS router, the IOS XR router must have a valid return path - either via a dynamic routing protocol or a configured static route - to reach the IOS peer. Without this return route, BFD control packets cannot be exchanged properly. LDP (A) is not required for BFD routing. IOS XR does support BFD multihop for IPv4 (B is false). BFD is interoperable between IOS XR and IOS (D is false), as BFD is a standards-based protocol (RFC 5880).

Topics

#BFD#IOS XR#IOS Interoperability#Routing Fundamentals

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