# Platform Considerations

You can configure unchannelized T3 and unchannelized E3 interfaces on the following E Series Broadband Services Routers:

- ERX1440 router
- ERX1410 router
- ERX710 router
- ERX705 router
- ERX310 router

  | Note: The E120 and E320 Broadband Services Routers do not support configuration of unchannelized T3/E3 interfaces.

For detailed information about the modules that support unchannelized T3/E3 interfaces on ERX7xx models, ERX14xx models, and the ERX310 router:

- See ERX Module Guide, Table 1, Module Combinations for detailed module specifications.
- See ERX Module Guide, Appendix A, Module Protocol Support for information about the protocols and applications that unchannelized T3/E3 modules support.

## COCX-F3 Line Modules and Associated I/O Modules

ERX7xx models, ERX14xx models, and the ERX310 router support the COCX-F3 line modules and associated I/O modules.

ERX14xx models support up to twelve COCX-F3 line modules and twelve corresponding I/O modules, ERX7xx models support up to five of these line modules and five corresponding I/O modules, and the ERX310 router supports up to two of these line modules and two corresponding I/O modules. There are twelve physical T3/E3 (DS3) ports per I/O module. Each port uses two SMB connectors: one for the transmit (TX) connection and one for the receive (RX) connection.

COCX-F3 line modules and associated I/O modules support the following:

- Clocking
- Redundancy
- Frame Relay logical interface support
- Unique IP interface support for each PPP or Frame Relay PVC interface
- HDLC
- Fractional T3 (T3 only)
- Line speeds of 45 Mbps (T3) and 34 Mbps (E3)

## OCx/STMx/DS3-ATM Line Modules and 4xDs3 ATM I/O Modules

ERX7xx models, ERX14xx models, and the ERX310 router support the OCx/STMx/DS3-ATM line modules and 4xDS3 ATM I/O modules.

ERX14xx models support up to twelve OCx/STMx/DS3-ATM line modules and twelve 4xDS3 ATM I/O modules, the ERX7xx models support up to five of these line modules and five corresponding I/O modules, and the ERX310 router supports up to two of these line modules and two corresponding I/O modules. There are four physical T3 (DS3) ports per I/O module. Each port uses two BNC connectors: one for the transmit (TX) connection and one for the receive (RX) connection.

OCx/STMx/DS3-ATM line modules pair with 4xDS3 ATM I/O modules to support the following:

- Clocking
- Redundancy
- Frame Relay logical interface support
- Unique IP interface support for each PPP or Frame Relay PVC interface
- Line speeds of 45 Mbps

## CT3/T3-F0 Line Modules and CT3/T3 12 I/O Modules

ERX7xx models, ERX14xx models, and the ERX310 Broadband Services Router support the CT3/T3-F0 line modules and CT3/T3 12 I/O modules.

The CT3/T3-F0 line module and CT3/T3 12 I/O module support both channelized and unchannelized T3 operation. You can configure a mixture of channelized and unchannelized ports on these modules. To configure these modules to support unchannelized T3 operation, issue no channelized . (See Configuration Tasks .) For information about configuring channelized T3 ports, see Configuring T3 and E3 Interfaces.

ERX14xx models support up to twelve CT3/T3-F0 line modules and twelve CT3/T3 12 I/O modules, ERX7xx models support up to five of these line modules and five corresponding I/O modules, and the ERX310 Broadband Services Router supports up to two of these line modules and two corresponding I/O modules. There are twelve physical T3 (DS3) ports per I/O module. Each port uses two SMB connectors: one for the transmit (TX) connection and one for the receive (RX) connection.

CT3/T3-F0 line modules and CT3/T3 12 I/O I/O modules to support the following:

- Clocking
- Redundancy
- Frame Relay logical interface support
- Unique IP interface support for each PPP or Frame Relay PVC interface
- Line speeds of 45 Mbps

## Interface Stack

Figure 3 shows the stack for T3 ATM interfaces. Figure 4 shows the stack for T3 frame and E3 frame interfaces.

To configure a T3 ATM interface, first configure a T3 controller. To configure ATM parameters, see Configuring ATM in JunosE Link Layer Configuration Guide .

To configure a T3 frame or E3 frame interface, first configure a T3 or E3 controller, and then configure a High-Speed Data Link Control (HDLC) data channel on the controller.

Figure 3: Stack for T3 ATM Interfaces

Figure 4: Stack for T3 Frame and E3 Frame Interfaces

| Note: For a detailed description of interface types and specifiers, see Interface Types and Specifiers in JunosE Command Reference Guide. For information about interfaces, see Planning Your Network in JunosE System Basics Configuration Guide.

## 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 ERX7xx models, line module slots are numbered 2-6 (slots 0 and 1 are reserved for SRP modules). In ERX14xx models, line module slots are numbered 0–5 and 8–13 (slots 6 and 7 are reserved for SRP modules). In the ERX310 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.