Click the exhibit. Router R1 is a route reflector with clients R2, R5 and R6. Router R3 advertises the prefix 192.168.1.0/27 to routers R5 and R6. Assuming that routers R1, R2 and R4 are configured…

Question

Options

• AFlag Network LocalPref MED Nexthop Path-Id VPNLabel As-Path u* >i 192.168.1.0/27 None None 10.10.10.5 1 65541 *i 192.168.1.0/27 None None 10.10.10.6 2 65541
• BFlag Network LocalPref MED Nexthop Path-Id VPNLabel As-Path u* >i 192.168.1.0/27 None None 10.10.10.5 65541 *i 192.168.1.0/27 None None 10.10.10.6 65541
• CFlag Network LocalPref MED Nexthop Path-Id VPNLabel As-Path u* >i 192.168.1.0/27 None None 10.10.10.1 1 65541 *i 192.168.1.0/27 None None 10.10.10.1 2 65541
• DFlag Network LocalPref MED Nexthop Path-Id VPNLabel As-Path u* >i 192.168.1.0/27 None None 10.10.10.1 65541 *i 192.168.1.0/27 None None 10.10.10.1 65541

• A
  75% (15)
• B
  5% (1)
• C
  5% (1)
• D
  15% (3)

Explanation

Option A is correct because when BGP Add-Paths is enabled with send 2, the route reflector (R1) advertises both paths it received from clients R5 and R6, assigning each a unique Path-Id (1 and 2) so the receiving router (R2) can distinguish them - and critically, a route reflector preserves the original next-hop of each path (10.10.10.5 for R5, 10.10.10.6 for R6) rather than replacing it with its own address.

B is wrong because even though the nexthops are correct (10.10.10.5 and 10.10.10.6), it omits the Path-Id column entirely - Add-Paths requires a Path-Id to differentiate multiple paths for the same prefix; without it, the second path would overwrite the first.

C is wrong because while it correctly shows Path-Ids 1 and 2, the nexthop for both paths is listed as 10.10.10.1 (R1 itself) - route reflectors do not modify the NEXT_HOP attribute when reflecting to iBGP clients; the original nexthop is always preserved.

D is wrong for both reasons combined: the nexthop incorrectly shows R1 (10.10.10.1) and Path-Ids are missing.

Memory tip: Think of a route reflector as a "transparent mirror" - it reflects routes without changing the nexthop, and Add-Paths is like putting numbered labels on each copy so the receiver knows they're distinct paths.

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