Refer to the exhibit. Router 1 is a route reflector client within a service provider core. PE1 cannot see VPNv4 routes received from the ASBR. PE1 only has an iBGP relationship with Router 1. Which…

Question

Exhibit

Options

• AActivate PE1 as a neighbor under the IPv4 address family.
• BConfigure Router 1 as a route reflector for PE1 under the VPNv4 address family.
• CConfigure PE1 to have an eBGP relationship with Router 1.
• DEnable BGP default ipv4-unicast

• A
  12% (3)
• B
  80% (20)
• C
  4% (1)
• D
  4% (1)

Explanation

Option B is correct because BGP route reflection is address-family specific in IOS - being configured as a route reflector client under the IPv4 unicast address family does not automatically extend to the VPNv4 address family. Router 1 must have route-reflector-client explicitly configured for PE1 under address-family vpnv4, otherwise VPNv4 prefixes received from the ASBR are never reflected toward PE1.

Why the distractors fail:

• A - Activating PE1 under the IPv4 address family affects only IPv4 unicast routes, not VPNv4; it solves the wrong problem.
• C - PE1 and Router 1 are in the same AS (SP core), so eBGP is architecturally incorrect here and wouldn't fix VPNv4 reflection anyway.
• D - bgp default ipv4-unicast auto-activates neighbors in the IPv4 unicast family; it has no bearing on VPNv4 route propagation.

Memory tip: Think of each BGP address family as a separate pipe - route reflection must be plumbed independently per pipe. If VPNv4 routes aren't flowing, ask "is the RR configured as route-reflector-client under vpnv4?" - that's almost always the culprit on SP exam scenarios.

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