JUNOS Enterprise Switching

EX Interfaces

This section begins with some general JUNOS interface concepts before providing EX-specific interface configuration, operational analysis, and troubleshooting examples typical to an initial configuration.

Historically, Juniper Networks routers contained two major categories of interfaces: permanent and transient. Users cannot remove permanent interfaces, whereas they can move, change, and remove transient interfaces. Transient interfaces are typically based on modular interfaces, which in turn are based on a Flexible PIC Concentrator (FPC) and Physical Interface Card (PIC) model, in which FPCs and PICs can be moved about as desired in the system.

The EX3200 and EX4200 are fixed interface platforms, and therefore do not directly support the modular interface model. However, because EX switches run JUNOS software, it can still be said that some EX interfaces are permanent in regard to their intended function—say, as a network management interface, or tunnel services device—whereas others are seen as user or network interfaces, with a broader range of network-oriented functions. The following sections detail the JUNOS-based interface devices that often cause confusion among new users.

Permanent Interfaces

A permanent interface is any interface that is always present on the switch (it cannot be altered). These interfaces can be management interfaces such as OoB Ethernet, or a software-based pseudointerface such as a tunnel service device.

An EX4200 has three permanent management ...