Refer to the exhibit. An engineer is trying to implement BGP configuration on a router. Which configuration error prevents the ASBR from establishing a BGP neighborship to a directly connected BGP…

The correct answer is A. The routing policy is absent for this Cisco IOS XR eBGP instance. On Cisco IOS XR, eBGP sessions have a strict requirement that an explicit routing policy must be applied to neighbors for both inbound and outbound directions before routes can be exchanged. Unlike IOS, IOS XR does not allow BGP sessions to pass routes without a defined…

Networking

Question

Refer to the exhibit. An engineer is trying to implement BGP configuration on a router. Which configuration error prevents the ASBR from establishing a BGP neighborship to a directly connected BGP speaker?

Exhibit

Options

AThe routing policy is absent for this Cisco IOS XR eBGP instance.
BThe IPv4 address family configuration under neighbor configuration-mode must be removed.
CThe VPNv4 address family interferes with the 8GP IPv4 address family negotiations.
DThe TCP session parameters are not specified.

How the community answered

(46 responses)

A
72% (33)
B
17% (8)
C
2% (1)
D
9% (4)

Explanation

On Cisco IOS XR, eBGP sessions have a strict requirement that an explicit routing policy must be applied to neighbors for both inbound and outbound directions before routes can be exchanged. Unlike IOS, IOS XR does not allow BGP sessions to pass routes without a defined route-policy. If no routing policy is configured and attached to the neighbor, the eBGP session may form at the TCP/BGP level but will not exchange any prefixes, effectively preventing full neighborship functionality. This is a fundamental IOS XR design difference from classic IOS, where routes are exchanged by default without explicit policies.

Topics

#BGP#IOS XR#eBGP#Routing Policy

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