In which configuration mode is a route distinguisher configured in a Cisco IOS XR router?

Question

Options

• Aconfig-vrf
• Bconfig-vrf-af
• Cconfig-bgp
• Dconfig-bgp-af
• Econfig-bgp-vrf

• A
  2% (1)
• B
  2% (1)
• D
  2% (1)
• E
  94% (47)

Explanation

On Cisco IOS XR, the route distinguisher (RD) is configured under router bgp <ASN> → vrf <name>, placing you in config-bgp-vrf mode - the rd command lives here, directly beneath the per-VRF stanza inside BGP. This differs from IOS/IOS-XE, where RD is set in the global VRF definition.

Why the distractors are wrong:

• A (config-vrf) - The global vrf <name> stanza on IOS XR defines address-families and import/export targets, but not the RD.
• B (config-vrf-af) - The address-family under the VRF definition handles RT and other AF-specific settings, not the RD.
• C (config-bgp) - The top-level BGP context sets global parameters (router-id, AS, etc.); VRF-specific settings require drilling into a VRF sub-context.
• D (config-bgp-af) - The address-family under BGP (e.g., address-family ipv4 unicast) configures network statements and redistribution, not per-VRF RDs.

Memory tip: Think "RD belongs to BGP's VRF" - on IOS XR, BGP owns the RD, so you go into BGP first, then into the VRF sub-mode (config-bgp-vrf). If you're not inside both BGP and a VRF context simultaneously, you're in the wrong place.

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