• Network Layer Reachability Information
    • Network Statement
      • MUST BE EXACT MATCH!
    • Redistribute Statement
      • Won’t include OSPF E1/2 by default.
    • Aggregate Address Statement
      • Requires one subnet in BGP Table first.
      • BGP inject-map
        • opposite of aggregation.

BGP Network Statement:

  • Originates prefixes with ORIGIN of IGP (i)
  • Requires exact match in the routing table
    • can be learned via IGP.
  • No mask keyword assumes classful.
  • Sets weight to 32768

BGP Redistribute Statement:

  • Originates prefixes with ORIGIN INCOMPLETE (?)
  • Originates classful summary if auto-summary is enabled.
  • Auto copies IGP metric to BGP MED.
  • Won’t include OSPF External by default.
    • redistribute ospf <id> match internal external
  • Sets weight to 32768.

BGP Redistribute Internal:

  • By default, only external BGP routes are redistributed into IGP with redistribution.
  • ‘bgp redistribute internal’ lets internal BGP routes to be redistributed into IGP.
  • Can result in a routing loop if not careful.

BGP Conditional Advertisement:

  • Advertises prefix matched in advertise-map.
    • If prefix matched in non-exist map does not exist
    • If prefix matched in exist-map does exist.
  • Typically used to track failure of a transit link.
    • Advertise to backup provider, only if primary provider is down.

BGP Conditional Route Injection:

  • Originates subnets from aggregate for purpose of longest match traffic engineering.
  • ‘bgp inject-map inject-map exist-map exist-map <copy attributes>
    • Inject map
      • subnet to be advertised
      • set ip address prefix-list<list>
    • Exist Map
      • Aggregate to be originated from
      • Match ip address prefix-list <list>
      • match ip route-source prefix-list <list>

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