Which of the following messages does BGP support? (Multiple choice)

Question

Options

• AHello
• BKeepalive
• CUpdate
• DOpen

• A
  13% (4)
• B
  80% (24)
• C
  3% (1)
• D
  3% (1)

Explanation

BGP actually supports B, C, and D - the answer key as presented appears to be incomplete. BGP defines four message types: OPEN (D), KEEPALIVE (B), UPDATE (C), and NOTIFICATION. All three of those choices are correct, making A the only true distractor.

A (Hello) is wrong because Hello messages belong to OSPF (and IS-IS), not BGP. This is the classic trap - confusing IGP mechanisms with eBGP's session management.

B, C, D are all correct: OPEN initiates the peer session and negotiates parameters; KEEPALIVE maintains the session between peers (sent every 60 seconds by default, with a 180-second hold timer); and UPDATE carries reachability information - prefixes, path attributes, and withdrawals.

Memory tip: Think "OUKN" - Open, Update, Keepalive, Notification. Or remember BGP has four messages and OSPF uses Hello - if you see "Hello" in a BGP question, it's always wrong.

Note for exam prep: If your source material lists only B as correct, double-check it - this may be a typo or a poorly written question. On real exams (CCNA, CCNP), you'd be expected to know all four BGP message types.

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