BGP - multiprotocol BGP
MP-BGP is an extension to the standard BGP, which allows it to carry routing information for multiple network protocols.
The "protocols" it supports are the following:
Each of the above is considered an address family in the context of MP-BGP. MP-BGP is also able to support the following fields which are necessary to enable it to support these various protocols:
- Address Family Identifier (AFI): specifies the address family.
- Subsequent Address Family Identifier (SAFI): Has additional information for some address families.
- Multiprotocol Unreachable Network Layer Reachability Information (MP_UNREACH_NLRI): This is an attribute used to transport networks that are unreachable.
- BGP Capabilities Advertisement: This is used by a BGP router to announce to the other BGP router what capabilities it supports. MP-BGP and BGP-4 are compatible, the BGP-4 router can ignore the messages that it doesn’t understand.