An Alcatel-Lucent 7750 SR receives a route from an iBGP peer with a MED value of 500. What MED value is sent to eBGP peers?

Question

Options

• A100
• BThe IGP cost
• C500
• DNone

• A
  13% (2)
• B
  7% (1)
• D
  80% (12)

Explanation

By default, BGP does not advertise MED values learned from iBGP peers to eBGP neighbors - the MED attribute is stripped before the route is sent externally. This is standard RFC behavior: MED is meant to influence how traffic enters your AS from a directly connected neighbor, and an internally-learned MED has no meaningful context for an eBGP peer.

Why the distractors are wrong:

• A (100): There is no default MED of 100 in BGP; the default MED when unset is 0, and even that wouldn't apply here.
• B (IGP cost): IGP cost is only used as MED if explicitly configured (e.g., metric-out igp); it is never applied automatically in this scenario.
• C (500): The MED received from an iBGP peer is not propagated - the router does not forward the internal MED value outbound to eBGP peers.

Memory tip: Think of MED as a "sticky note" valid only at the border where it was received. Once a route travels across your AS via iBGP, the sticky note is discarded before it leaves your AS again - eBGP peers receive the route with no MED (None).

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