JUNOS Enterprise Routing

Interface Configuration Examples

A walkthrough of configuration examples, starting with basic examples and then getting into a few more complex configurations, will help to put this into perspective. The order of the walkthrough uses the following configuration example:

Fast Ethernet interfaces

Fast Ethernet with VLAN tagging

T1 interface with Cisco HDLC

Serial interface with PPP

Serial interface with Frame Relay

DSL

ISDN

MLPPP

Initially, we will use a step-by-step approach to establish the configuration fundamentals. Then the walkthrough will move toward configuration results that build on the fundamentals and become advanced. Once you grasp the fundamentals, you should be able to follow the advanced configurations. At the end of this section, we will discuss the use of the Virtual Router Redundancy Protocol (VRRP).

Fast Ethernet Interface

First, let’s build an interface on router Lager that connects directly to router Ale over the fe-0/0/0 interface.

Check the status of the fe-0/0/0 interface by issuing a show interfaces fe-0/0/0 terse command. JUNOS software interfaces are automatically “enabled” when the physical connection is wired.

root@Lager>show interfaces terse fe-0/0/0
Interface               Admin Link Proto    Local            Remote
fe-0/0/0                up    up

Tip

If an interface needs to be administratively disabled, issue the set interfaces <interface name> disable command.

The interface appears to be physically up, so next, configure the interface to allow IP traffic to flow as well as add an IP address. Begin by ...