Please match the following BGP attribute names with their attribute categories. (Drag and drop)

Question

Options

• AOrigin: Recognized as obligatory; Local Preference: Recognized as arbitrary; Aggregator: optional transition; MED: optional non-transitional.
• B
• C
• D

• A
  76% (48)
• B
  14% (9)
• C
  3% (2)
• D
  6% (4)

Explanation

Option A is correct because each BGP attribute is matched to its proper RFC-defined category. Origin is Well-Known Mandatory (obligatory), meaning all BGP routers must recognize it and it must appear in every UPDATE message. Local Preference is Well-Known Discretionary (arbitrary), meaning all routers must recognize it but it does not have to be present in every update. Aggregator is Optional Transitive, meaning routers that do not recognize it will still pass it along to peers, while MED (Multi-Exit Discriminator) is Optional Non-Transitive, meaning unrecognized routers will silently drop it rather than forward it. Options B, C, and D are not populated in this question, so A is the only viable match by elimination, though the pairings themselves are factually accurate regardless.

Memory tip: Use the phrase "Mandatory Moves Along, Discretionary Drops" to recall the four categories in order -- Well-Known Mandatory (must recognize, must include), Well-Known Discretionary (must recognize, optional inclusion), Optional Transitive (may not recognize, but forwards it), Optional Non-Transitive (may not recognize, and drops it). Then anchor the four attributes: Origin is the most fundamental so it is mandatory; Local Preference is flexible within an AS so it is discretionary; Aggregator labels summarized routes and travels with them (transitive); MED hints at entry points but stays local (non-transitive).

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