Bgp4+ Overview; Bgp4+ Features Supported By The S6700 - Huawei S6700 Series Configuration Manual

S6700 Series Ethernet Switches
Configuration Guide - IP Routing

8.1 BGP4+ Overview

BGP4+ is mainly used to control route transmission and select optimal routes.
BGP4+ is a dynamic routing protocol used between Autonomous Systems (ASs), and it is an
extension of BGP.
The traditional BGP4 can manage only the IPv4 routing information. For other network layer
protocols such as IPv6, the traditional BGP4 has a limited capability to transmit routing
information.
The IETF introduces BGP4+ as a supplement to BGP4 to support multiple network layer
protocols. The RFC for BGP4+ is RFC 2858 (Multiprotocol Extensions for BGP4).
To support IPv6, BGP4 needs to reflect the IPv6 protocol information to the Network Layer
Reachable Information (NLRI) attribute and the Next_Hop attribute.
BGP4+ introduces two NLRI attributes:
l
l
The Next_Hop attribute of BGP4+ is in the format of an IPv6 address. It can be an IPv6 global
unicast address or the link-local address of the next hop.
BGP4+ can be applied to an IPv6 network by using the BGP attribute of multiple protocol
extension. The message and routing mechanisms of BGP remain unaltered.

8.2 BGP4+ Features Supported by the S6700

The system supports various BGP4+ features, including load balancing, route aggregation, route
dampening, community, route reflector, confederation, BGP4+ accounting, 6PE, BFD for BGP4
+, BGP4+ GR, and BGP4+ NSR.
6PE
After the 6PE function is enabled, the separated IPv6 networks can be connected through the
Multi-Protocol Label Switch (MPLS) tunnel technology. The tunnel in 6PE mode implements
the dual protocol stack of IPv4/IPv6 on PEs of the Internet Service Provider (ISP). It identifies
IPv6 routes by using the label assigned by the Multiprotocol Border Gateway Protocol (MP-
BGP), and implements IPv6 interworking through LSPs between PEs.
Other Attributes
Most of BGP4+ features supported by the S6700 are similar to those of BGP supported by the
S6700. For details, refer to the chapter "BGP Configuration".
BGP4+ does not support summary automatic and MP-BGP.
Issue 01 (2012-03-15)
Multiprotocol Reachable NLRI (MP_REACH_NLRI): advertises the reachable routes and
the next hop information.
Multiprotocol Unreachable NLRI (MP_UNREACH_NLRI): withdraws the unreachable
routes.
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