Which of the following description about BGP features is wrong?

Question

Options

• ABGP is an external routing protocol used to transfer routing information between ASs
• BBGP is a path vector protocol
• CBGP has rich route filtering and routing policies
• DBGP supports CIDR

• A
  3% (1)
• B
  83% (25)
• C
  3% (1)
• D
  10% (3)

Explanation

Important caveat first: This answer key appears to contain an error. Option B ("BGP is a path vector protocol") is actually a true and correct statement about BGP - it is one of BGP's defining characteristics per RFC 4271. If B is marked as the "wrong" description, the exam key is incorrect.

Here's why all four options are actually correct descriptions of BGP:

• A is correct - BGP (Border Gateway Protocol) is indeed an Exterior Gateway Protocol (EGP) that exchanges routing information between Autonomous Systems (ASes).
• B is correct - BGP is definitively classified as a path vector protocol, meaning it advertises the full AS-path to each destination, not just a hop count or distance metric. This distinguishes it from RIP (distance vector) and OSPF (link-state).
• C is correct - BGP is well-known for extensive support of route filtering, route maps, and fine-grained routing policies (community attributes, local preference, MED, etc.).
• D is correct - BGP fully supports Classless Inter-Domain Routing (CIDR), including prefix aggregation (supernetting), which is central to its role in the global internet routing table.

Memory tip: BGP is the "big" protocol of the internet - it connects the world's ASes (A), uses path vectors (B), has powerful policies (C), and speaks CIDR (D). All four are core BGP facts worth memorizing regardless of this question's flawed key.

If this is a Huawei/vendor certification exam, double-check the source - the intended "wrong" answer may have been transcribed incorrectly.

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