The system supports an SRP module and a selection of line modules. You can use any line module for access or uplink. Access line modules receive traffic from low-speed circuits, and the system routes the traffic onto higher-speed uplink line modules and then to the core of the network.
Each module connects to a corresponding I/O module via a passive midplane. See Figure 1-11.
The front panel of each module contains a collection of status LEDs (light-emitting diodes). For information about how to interpret the LEDs, see Chapter 10, Troubleshooting.
Switch route processor (SRP) modules perform system management, routing table calculations and maintenance, forwarding table computations, statistics processing, configuration storage, and other control plane functions. Each SRP module is a PowerPC-based system with its own memory, nonvolatile disk storage, and power supply (see Figure 1-12 and Figure 1-13).
ERX-7xx/14xx models use up to two redundant SRP modules operating in an active/standby configuration. ERX-310 routers use only one SRP module. An SRP module must be present for any system to boot.
SRP modules ranging from 5 Gbps to 40 Gbps can be used in ERX-7xx/14xx models. Only a 10-Gbps SRP module (SRP-SE10G) can be used in ERX-310 routers. See Chapter 12, Module Specifications for complete information.
Note: Because of different physical dimensions and switch fabric capabilities, SRP modules are not interchangeable between systems. For example, the 10-Gbps SRP module used in ERX-7xx/14xx models cannot be used in the ERX-310 router, and vice versa.
Caution: Do not remove the SRP module while the system is running.
For details about installing SRP modules, see Chapter 5, Installing Modules.
SRP Module Redundancy
SRP module redundancy is available only for ERX-7xx/14xx models. See Redundancy Features, later in this chapter, for more information.
The PCMCIA slot on the front of the SRP module holds a Type II PCMCIA nonvolatile storage (NVS) card (see Figure 1-12 and Figure 1-13). This card is loaded with the system's software and configuration files. The PCMCIA card is factory installed.
SRP I/O Module
The SRP I/O module is a single corresponding input/output module that interfaces with the SRP module(s) through the system's midplane. The same SRP I/O module works with all SRP modules, but is router specific. The I/O module used in ERX-7xx/14x models cannot be used in the ERX-310 router, and vice versa. See Figure 1-5, Figure 1-7, and Figure 1-9 for locations.
The SRP module provides standard craft management interfaces, including:
- 10/100Base-T - Enables access to the E-series router for Ethernet management functions via CLI or SNMP, for example.
- RS-232 - Provides a serial connection for monitoring the system's hardware configuration through a PC (running terminal emulation software) or ASCII terminal. Allows direct CLI access.
- Alarm contacts - Provide for remote indication of critical, major, and minor E-series router alarms (ERX-7xx/14xx models only; currently not implemented)
- External timing inputs - Provide a method of ensuring that the clock timing used by the E-series router remains synchronized with the network's system clock. BNC connectors and wire wraps are available for ERX-7xx/14xx models only.
For details about installing the SRP I/O module, see Chapter 5, Installing Modules.
Line modules process data from different types of network connections. For information about available line modules and which SRP modules support specific line modules, see Chapter 12, Module Specifications.
Figure 1-14 shows a representative line module. For details about installing line modules, see Chapter 5, Installing Modules.
Most line modules support packet classification on ingress (some non-ASIC line modules do not). A classification engine on the line module matches specific fields (such as source and destination IP address, source and destination port, and protocol), the ingress IP interface, layer 2 fields, or some combination of these against user-configured filters at wire speed.
Most line modules have a corresponding input/output (I/O) module that provides the physical interconnection to the network. Insert each I/O module into the back of the system, directly behind its corresponding line module.
For information about which line modules pair with which I/O modules, see Chapter 12, Module Specifications. See Figure 1-5, Figure 1-7, and Figure 1-9 for locations. For details about installing I/O modules, see Chapter 5, Installing Modules.