Routers C and E are route reflectors. When the update for prefix 192.168.2.0/24 is received at router F, what will be the Originator_ID attribute?

Question

Options

• AThe router ID of router A.
• BThe router ID of router B.
• CThe router ID of router C.
• DIt will not be set.

• A
  4% (1)
• B
  71% (20)
• C
  7% (2)
• D
  18% (5)

Explanation

Option B is correct because the ORIGINATOR_ID attribute is set by the first route reflector (Router C) to the Router ID of the iBGP peer that originally sent it the route - which is Router B, the originator of 192.168.2.0/24. Once set, subsequent route reflectors (like Router E) leave it unchanged, so Router F sees Router B's Router ID.

Why the distractors fail:

• A (Router A): Router A is not in the path of origination for this prefix - Router B is the source.
• C (Router C): The RR sets ORIGINATOR_ID to its client's Router ID (Router B), not its own - that would be the CLUSTER_LIST attribute.
• D (Not set): ORIGINATOR_ID is always added when a route reflector first reflects a route; it's mandatory in route reflection to prevent loops.

Memory tip: Think of ORIGINATOR_ID as a "birth certificate" - it records who gave birth to the route in iBGP (the originating peer), not who carried it (the reflector). The reflector's identity goes into CLUSTER_LIST, not ORIGINATOR_ID.

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