H3C Technologies H3C S10500 Series Switches - Manual (Page 337)

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IPv6 BGP configuration
NOTE:
•
The term router in this document refers to both routers and Layer 3 switches.
• This chapter describes only configuration for IPv6 BGP. For BGP related information, see the chapter
“BGP configuration.”
IPv6 BGP overview
BGP-4 was designed to carry only IPv4 routing information, so other network layer protocols such as IPv6
are not supported.
To support multiple network layer protocols, IETF extended BGP-4 by introducing Multiprotocol BGP
(MP-BGP), which is defined in RFC 2858 (multiprotocol extensions for BGP-4).
For brevity purposes, MP-BGP for IPv6 is called “IPv6 BGP.”
IPv6 BGP puts IPv6 network layer information into the attributes of Network Layer Reachability
Information (NLRI) and NEXT_HOP.
The NLRI attribute of IPv6 BGP involves the following:
• MP_REACH_NLRI: Multiprotocol Reachable NLRI, for advertising reachable route and next hop
information.
• MP_UNREACH_NLRI: Multiprotocol Unreachable NLRI, for withdrawal of unreachable routes.
The NEXT_HOP attribute of IPv6 BGP is identified by an IPv6 unicast address or IPv6 local link address.
IPv6 BGP has the same messaging and routing mechanisms as BGP.