Bgp Peer And Peer Group; Bgp Configuration Task List - H3C S7500 Series Operation Manual

Operation Manual – Routing Protocol
H3C S7500 Series Ethernet Switches
II. BGP route selection policies
In the implementation on the S7500 series, BGP adopts the following policies for
route selection:
Discard next-hop-unreachable routes;
Prefer the routes with the highest local-preference;
Prefer the routes originated from the local router;
Prefer the routes traversing the least ASs (that is, the routes with the shortest
AS-Path);
Prefer the routes with the lowest Origin type;
Prefer the routes with the lowest MED value;
Prefer the routes learned from EBGP;
Prefer the routes advertised from the router with the lowest BGP ID.

6.1.4 BGP Peer and Peer Group

I. Definition
As described in section
of exchanging BGP messages with each other are peers of each other. A BGP peer
group is a set of BGP peers.
II. Relationship between peer and peer group
In the S7500 series, a BGP peer cannot exist independently; it must belong to a peer
group. Therefore, when you configure a BGP peer, make sure you first create a BGP
peer group, and then add a peer to the group.
BGP peer groups bring convenience for configuration. Once a peer is added to a peer
group, the peer will inherit the same configuration of the peer group. This can simplify
configuration in many cases. In addition, adding peers to a peer group can improve
route advertisement efficiency.
When the configuration of a peer group changes, the configuration of group members
also changes accordingly. For some attributes, you can configure them on a particular
member by specifying an IP address; the attribute settings you made in this way on a
member take precedence over the attribute settings on the peer group. Note that, the
members and the group must have consistent route update policies, but they can
have different entrance policies.

6.2 BGP Configuration Task List

Complete the following tasks to configure BGP:
6.1.3 "BGP Routing Mechanism", two BGP speakers capable
6-6
Chapter 6 BGP Configuration