BGP Path attributes in BGP are attributes that all BGP routers must recognize and be included in Update messages.

Question

Options

• ATRUE
• BFALSE

• A
  25% (7)
• B
  75% (21)

Explanation

Option B (FALSE) is correct because the statement describes only well-known mandatory attributes - just one of the four BGP path attribute categories. BGP actually defines four types: well-known mandatory, well-known discretionary, optional transitive, and optional non-transitive.

Why A is wrong: Not all BGP path attributes are required to be recognized by every router or included in every Update message. Only well-known mandatory attributes (e.g., AS_PATH, NEXT_HOP, ORIGIN) carry both of those requirements simultaneously.

The key distinctions:

• Well-known discretionary (e.g., LOCAL_PREF) - must be recognized by all routers but does not have to appear in every Update
• Optional transitive (e.g., COMMUNITY) - does not have to be recognized; if unrecognized, the router passes it along
• Optional non-transitive (e.g., MED) - does not have to be recognized; if unrecognized, the router drops it

Memory tip: Think of the two "well-known" types as "known to all, but only mandatory ones must show up." Use the mnemonic "M = Must include, D = Doesn't have to" - Mandatory vs. Discretionary - to keep them straight on exam day.

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