Interfaces; Subinterfaces; Interface Command - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - SYSTEM BASICS CONFIGURATION GUIDE 2010-10-04 Configuration Manual

JunosE 11.3.x System Basics Configuration Guide

Interfaces

Subinterfaces

interface Command

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For a complete list of the line modules and I/O modules available for ERX14xx models,
ERX7xx models, and the ERX310 router, see ERX Module Guide, Table 1, Module
Combinations. For more information about line modules and IOAs available with the E120
and E320 routers, see E120 and E320 Module Guide, Table 1, Modules and IOAs.
For more information about managing these modules, see "Managing Modules" on
page 341.
The term interfaces is used in a very specific way in the JunosE CLI and this documentation.
Interfaces are both physical and logical channels on the router that define how data is
transmitted to and received from lower layers in the protocol stack. Conceptually, you
configure an interface as part of the physical layer, layer 1.
For example, you can configure the physical and logical characteristics of T3 and T1 lines
coming directly from the customer premises or from a central office switch and OC3 lines
going out to the core of your network infrastructure. These physical and logical
characteristics define an interface.
Interface layering must always be configured in order from the lowest layer to the highest
layer. For example, if you have already configured IP to run over ATM and you want to
reconfigure the interface to run IP over PPP over ATM, you must first remove the IP
interface, apply PPP, and then reapply IP.
A subinterface is a mechanism that allows a single physical interface to support multiple
logical interfaces or networks. Several logical interfaces or networks can be associated
with a single physical interface. Configuring multiple virtual interfaces, or subinterfaces,
on a single physical interface allows greater flexibility and connectivity on the network.
Protocols such as Frame Relay and ATM require that you create one or more virtual
circuits over which your data traffic is transmitted to higher layers in the protocol stack.
The router requires that you define a subinterface on top of a physical interface as a
platform for a virtual circuit, such as a permanent virtual circuit (PVC).
Once you have defined the underlying characteristics of an interface, use the interface
command to:
Assign an interface type, such as POS or ATM.
1.
Assign the associated interface specifier to the interface, such as the slot/port or
2.
slot/adapter/port and channel/subchannel.
Assign one or more subinterfaces.
3.
The interface command has the following format:
interface interfaceType interfaceSpecifier
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