350-401 Question 470
Select 3A network administrator is configuring a BGP session between two routers in different autonomous systems. The administrator wants the BGP session to support both IPv4 and IPv6 address families. Which configuration steps are necessary to achieve this?
- A
Enable the 'neighbor activate' command under the desired address family for both IPv4 and IPv6.
- B
Use the 'address-family ipv4' and 'address-family ipv6' commands under the BGP process to define the address families.
- C
Apply a route-map to the neighbor to redistribute IPv4 and IPv6 prefixes.
- D
Configure a separate BGP session for IPv4 and IPv6 address families.
- E
Enable the 'no bgp default ipv4-unicast' command to explicitly define the address families.
Show answer and explanation
Correct answers: A, B, E
Explanation
To configure support for both IPv4 and IPv6 address families in BGP, the administrator needs to explicitly define the address families using the 'address-family' commands. The 'neighbor activate' command is necessary to activate each address family for a specific neighbor, and the 'no bgp default ipv4-unicast' command ensures explicit configuration of address families. These steps ensure proper BGP functionality and support for both address families.
- A. Correct.
Correct: The 'neighbor activate' command is required to activate the specific address family (IPv4 or IPv6) for a BGP neighbor.
- B. Correct.
Correct: The 'address-family ipv4' or 'address-family ipv6' commands are used to enable and configure the respective address families in the BGP process.
- C. Incorrect.
Incorrect: Applying a route-map is not a required step for enabling address families. Route-maps are used for filtering or manipulating routes, not for enabling address families.
- D. Incorrect.
Incorrect: A single BGP session can support multiple address families. Separate sessions are not required.
- E. Correct.
Correct: The 'no bgp default ipv4-unicast' command is used to avoid automatic activation of the IPv4 unicast address family, allowing explicit configuration of address families.