Consider two Alcatel-Lucent 7750 SRs in AS 65540. Router R1 has system address 10.10.10.1, and router R2 has system address 10.10.10.2. Which of the following configurations on router R2 can…

Question

Options

• Agroup "iBGP" family ipv4 peer-as 65540 neighbor 10.10.10.1 peer-as 65550 exit
• Bgroup "iBGP" family ipv6 peer-as 65540 neighbor 10.10.10.1 family ipv4 exit
• Cgroup "iBGP" family ipv4 peer-as 65540 local-address 10.10.10.1 neighbor 10.10.10.1 exit
• Dgroup "iBGP" family ipv4 peer-as 65540 local-address 10.10.10.2 neighbor 10.10.10.1 exit

• A
  8% (4)
• B
  12% (6)
• C
  4% (2)
• D
  77% (40)

Explanation

Option D is correct because it properly identifies R2 as the session initiator: peer-as 65540 correctly targets R1's AS (same AS = iBGP), neighbor 10.10.10.1 points to R1's system address, and critically, local-address 10.10.10.2 sets R2's own system address as the BGP session source - which is required for the TCP session to establish successfully.

Option A fails because the neighbor-level peer-as 65550 overrides the group-level peer-as 65540, making R2 expect an eBGP peer in AS 65550, which will never match R1's actual AS 65540. Option B fails because the group is configured with family ipv6, which conflicts with establishing a session to the IPv4 neighbor 10.10.10.1, and no local-address is specified. Option C is the trickiest distractor - it sets local-address 10.10.10.1, which is R1's address, not R2's; R2 does not own that address and cannot bind to it as a source.

Memory tip: For local-address, think "I am R2, so I source from my address (10.10.10.2)." The neighbor is where you're going; local-address is where you're leaving from - they must never be the same address.

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