User manual

Nortel Secure Router 8000 Series
Configuration -WAN Access 5 Logical interface configuration
Issue 5.3 (
30 March 2009) Nortel Networks Inc. 5-13
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5.4.4 Checking the configuration
Run the following commands to check the previous configuration.
Action Command
Check the status of a VE
interface.
display interface virtual-ethernet [ ve-number ] [ | { begin
| exclude | include } regular-expression ]
5.5 Configuring a loopback interface
5.5.1 Establishing the configuration task
Applicable environment
You use the loopback interface to improve reliability because it always remains in the Up
state and has loopback characteristics.
You use the loopback interface in two situations.
z
When you designate the IP address of the loopback interface as the source address of
packets
z
Controlling the access interface and filtering log based on the IP address simplify
information.
Generally, BGP uses the optimal local address to set up the TCP connection with its neighbor.
If the interface turns to Down, the BGP neighbor relationship cannot be set up. In practice,
often more than one link can reach the same neighbor. In this situation, using the loopback
interface as the BGP neighbor of the local router can ensure reliable connection.
Preconfiguration tasks
Before configuring a loopback interface, install and power on the router properly.
Data preparation
To configure a loopback interface, you need the following data.
No. Data
1 Number of the loopback interface
2 IP address of the loopback interface