Which statement regarding the Cisco IOS BGP configuration exhibit is correct?
A.
None of the routers will receive IPv4 BGP routes.
B.
Only the 172.16.2.1 and 172.16.3.1 neighbors will receive both VPNv4 routes and IPv4 BGP
routes.
C.
Only the 172.16.3.1 neighbor will receive both VPNv4 routes and IPv4 BGP routes.
D.
All three neighbors (172.16.1.1, 172.16.2.1, and 172.16.3.1) will receive both VPNv4 routes and
IPv4 BGP routes.
E.
All three neighbors (172.16.1.1, 172.16.2.1, and 172.16.3.1) will receive IPv4 BGP routes.
Explanation:
bgp default ipv4-unicast
To set the IP version 4 (IPv4) unicast address family as default for BGP peering session establishment, use the bgp default ipv4-unicast command in router configuration mode.
IPv4 address family routing information is advertised by default for each BGP routing session configured with the neighbor remote-as command, unless you first configure the no bgp default ipv4-unicast command before configuring the neighbor remote-as command.
The bgp default ipv4-unicast command is used to enable the automatic exchange of IPv4 address family prefixes. The neighbor activate address family configuration command must be entered in each IPv4 address family session before prefix exchange will occur.