User guide

Configuring BGP Configuring a BGP Peer
OmniSwitch AOS Release 7 Advanced Routing Configuration Guide March 2015 page 4-31
Setting Peer Authentication
You can set which MD5 authentication key this router will use when contacting a peer. To set the MD5
authentication key, enter the peer IP address and key with the ip bgp neighbor md5 key command:
-> ip bgp neighbor 123.24.5.6 md5 key keyname
The peer with IP address 123.24.5.6 will be sent messages using “keyname” as the encryption password. If
this is not the password set on peer 123.24.5.6, then the local router will not be able to communicate with
this peer.
Configuring the advertising of IPv4 routes for an IP BGP peer
You can enable or disable the advertising of IPv4 routes on an IPv4 neighbor. To enable the advertisement
of IPv4 unicast capability to the IPv4 BGP peer, use the following command:
-> ip bgp neighbor 172.22.2.115 activate-ipv4
The advertising capability is enabled for the BGP peer with IP address 172.22.2.115.
Note. The advertisement of IPv4 unicast capability is enabled by default.
To disable the advertising capability use the no form of the command.
-> no ip bgp neighbor 172.22.2.115 activate-ipv4
Setting the Peer Route Advertisement Interval
The route advertisement interval specifies the frequency at which routes external to the autonomous
system are advertised. These advertisements are also referred to as UPDATE messages. This interval
applies to advertisements to external peers.
To set the advertisement interval, enter the number of seconds in conjunction with the
ip bgp neighbor advertisement-interval command, as shown:
-> ip bgp neighbor 123.24.5.6 advertisement-interval 50
The interval is now set to 50 seconds.
Configuring a BGP Peer with the Loopback0 Interface
Loopback0 is the name assigned to an IP interface to identify a consistent address for network
management purposes. The Loopback0 interface is not bound to any VLAN, so it will always remain
operationally active. This differs from other IP interfaces in that if there are no active ports in the VLAN,
all IP interface associated with that VLAN are not active. In addition, the Loopback0 interface provides a
unique IP address for the switch that is easily identifiable to network management applications.
It is possible to create BGP peers using the Loopback0 IP interface address of the peering router and
binding the source (i.e., outgoing IP interface for the TCP connection) to its own configured Loopback0
interface. The Loopback0 IP interface address can be used for both Internal and External BGP peer
sessions. For EBGP sessions, if the External peer router is multiple hops away, the ebgp-multihop
parameter may need to be used.
The following example configures a BGP peering session using a Loopback0 IP interface address: