254
•
If no router ID is specified in BGP view, the global router ID is used. For information about
global router ID, see
IP Routing Basics
in the
Layer 3 – IP Routing Configuration Guide
.
•
If the global router ID is used and then it is removed, the system will select a new router ID.
If the router ID is specified in BGP view, using the
undo router-id
command can make the
system select a new router ID.
To do…
Use the command…
Remarks
Step 1
Enter system view
system-view
—
Step 2
Enable BGP and enter
BGP view
bgp
as-number
—
Not enabled by default
Step 3
Specify a router ID
router-id
ip-address
Optional
By default, the global router ID is
used.
Step 4
Specify a peer or a
peer group and its AS
number
peer
{
group-name | ip-address
}
as-number
as-number
Required
Not specified by default
Step 5
Enable the default use
of IPv4 unicast address
family for the peers that
are established using
the
peer as-number
command
default ipv4-unicast
Optional
Enabled by default
Step 6
Enable a peer
peer
ip-address
enable
Optional
Enabled by default
Step 7
Configure a description
for a peer or peer
group
peer
{
group-name
|
ip-address
}
description
description-text
Not configured by default
•
A router can reside in only one AS, so the router can run only one BGP process.
•
You must create a peer group before configuring it.
Specifying the source interface for TCP connections
BGP uses TCP as the transport layer protocol. By default, BGP uses the output interface of the
optimal router to a peer as the source interface for establishing TCP connections to the peer. If a
BGP router has multiple links to a peer, when the source interface fails, BGP has to reestablish
TCP connections, causing network oscillation. Therefore, it is recommended to use a loopback
interface as the source interface to enhance stability of BGP connections.
