H3C S9500 Series Operation Manual page 306

Operation Manual – Routing Protocol
H3C S9500 Series Routing Switches
When multiple network layer protocols are supported, it is necessary for BGP-4 to
reflect the information of the specified network layer protocol to NLRI and the Next_Hop.
Two new routing attributes are introduced in MBGP:
MP_REACH_NLRI: Multiprotocol Reachable NLRI, used to advertise reachable
routes and the next hop information.
MP_UNREACH_NLRI: Multiprotocol Unreachable NLRI, used to delete
unreachable routes.
These two attributes are optional non-transitive. Therefore, the BGP speaker that does
not provide multiple protocols ability will ignore the information of them nor transfer
them to other peers.
III. Address family
The network layer protocols are differentiated by address families in BGP. See
RFC1700 (assigned numbers) for the possible values of these address families. S9500
series provide various MBGP extended applications, including extension of multicast,
VPN, and so on. Different extended applications should be configured in their own
address family views.
For more information about the commands executed in MBGP address family view, see
"Multicast Protocol" and "MPLS Configuration" of this manual.
6.1.5 BGP Peer and Peer Group
I. Definition of peer and peer group
As described in Section 6.1.3 "BGP Routing Mechanism", BGP speakers among which
messages are exchanged are peers to one another. Multiple related peers compose a
peer group, and multiple related peers compose a peer group.
II. Relationship between peer configuration and peer group configuration
In S9500 series, a BGP peer must belong to a peer group. If you want to configure a
BGP peer, you need first to create a peer group and then add a peer into the group.
BGP peer group feature can simplify user configuration and improve route
advertisement efficiency. When added into a peer group, a peer inherits all the
configuration of the group.
If the configuration of a peer group changes, the configuration of its member peers also
alters. Some attributes can be configured to a particular member peer by specifying its
IP address. The attributes configured in this way is with higher priority than those by
configuring for peer group. It should be noted that all member peers must use the same
update policy as its group, but may use different ingress policy.
6-4
Chapter 6 BGP Configuration