peer connect-interface (BGP)
Function
The peer connect-interface command specifies the source interface through which the BGP packets are sent, and the source address with which the BGP connection is established.
The undo peer connect-interface command restores the default setting.
By default, the outbound interface of packets is used as the source interface of BGP packets by BGP.
Format
peer { group-name | ipv4-address | ipv6-address } connect-interface interface-type interface-number [ ipv4-source-address | ipv6-source-address ]
undo peer { group-name | ipv4-address | ipv6-address } connect-interface
Parameters
| Parameter | Description | Value |
|---|---|---|
| group-name | Specifies the name of the peer group. | The name is a string of 1 to 47 characters without any space. It is case-sensitive. |
| ipv4-address | Specifies the IPv4 address of the peer. | - |
| ipv6-address | Specifies the IPv6 address of the peer. | - |
| interface-type interface-number | Specifies the type and the number of the interface. | - |
| ipv4-source-address | Specifies source IPv4 address used in the establishment of a connection. | - |
| ipv6-source-address | Specifies source IPv6 address used in the establishment of a connection. | - |
ipv4-address is valid only in the BGP view and BGP-VPN instance IPv4 address family view.
ipv6-address is valid only in the BGP view and BGP-VPN instance IPv6 address family view.
Views
BGP view, BGP-VPN instance IPv4 address family view, BGP-VPN instance IPv6 address family view
Usage Guidelines
Usage Scenario
To establish a BGP peer connection between two indirectly connected physical interfaces, the peer connect-interface command must be run on both sides.
To establish a BGP peer connection between a local loopback interface and a remote interface, the loopback interface must be specified as the source interface in the command. To establish a BGP peer connection between a local physical interface and a remote interface, the physical interface must be specified as the source interface in the command.
- If multiple IP addresses are configured for the physical interface that needs a BGP peer connection established with a remote interface, the peer connect-interface command must be run, with ipv4-source-address or ipv6-source-address set to the source IP address.
- If two devices need multiple BGP peer connections established through different interfaces, the peer connect-interface command must be run for each BGP peer connection, with the source interface specified.
Configuration Impact
Running the peer connect-interface command causes the teardown and re-establishment of peer relationships.
Because the BGP peer relationships in various address families on the same device share one TCP connection, connect-interface configured in the BGP view can be inherited in either the IPv4 unicast address family or the VPNv4 address family.
Precautions
To enable a device to send BGP packets even if its physical interface fails, you can configure the device to use a loopback interface as the source interface of the BGP packets. When configure a device to use a loopback interface as the source interface of BGP packets, note the following points:
The loopback interface of the device's BGP peer must be reachable.
In the case of an EBGP connection, the peer ebgp-max-hop command needs to be run to enable the two devices to establish an indirect peer relationship.
If the specified interface borrows the IP address of another interface and then the IP address of the specified interface is changed, BGP still uses the borrowed IP address to keep the connection if no connection reestablishment is triggered, and data receiving and sending is not affected; if connection reestablishment is triggered, BGP uses the new IP address to reestablish the connection.