In the BGP protocol, which of the following BGP attributes can be used to mark routes with certain common characteristics so that other BGP routers can identify them?

Question

Options

• ACommunity
• BAS-path
• CLocal-pref
• DMED

• A
  80% (35)
• B
  2% (1)
• C
  7% (3)
• D
  11% (5)

Explanation

BGP Community is a well-known optional transitive attribute that allows network administrators to tag routes with arbitrary values, enabling routers across different autonomous systems to identify and apply consistent policies to groups of routes sharing common characteristics. AS-path records the sequence of autonomous systems a route has traversed and is primarily used for loop prevention and path selection, not for grouping routes by shared traits. Local-pref influences the preferred exit point for outbound traffic within a single AS and is not propagated to external BGP peers, so it cannot be used to mark routes for other BGP routers broadly. MED (Multi-Exit Discriminator) suggests to an external neighbor which entry point into your AS is preferred, but it is a metric for influencing inbound traffic, not a tagging mechanism for shared route characteristics.

Memory tip: Think of Community as a "label" or "tag" you stick on a route - just like a tag on a product groups it into a category that anyone who sees it can act on. The other three attributes (AS-path, Local-pref, MED) each serve a specific directional or selection purpose rather than a general classification role.

No community discussion yet for this question.