Numbering Scheme

This section describes how to identify T3 and E3 interfaces.

A T3/E3 controller on an ATM or frame interface is identified using the slot/port format, where:

slot—Number of the slot in which the line module resides in the chassis. In ERX-7xx models, line module slots are numbered 2-6 (slots 0 and 1 are reserved for SRP modules). In ERX-14xx models, line module slots are numbered 0–5 and 8–13 (slots 6 and 7 are reserved for SRP modules). In the ERX-310 router, the line module slots are numbered 0–2 (slot 0 is reserved for the SRP module).
port—Number of the port on the I/O module. On the CT3/T3 12 I/O and E3-12 FRAME I/O modules, ports are numbered 0–11.

For information about installing line modules and I/O modules in ERX routers, see ERX Hardware Guide, Chapter 4, Installing Modules.