T640 Routing Engine Description
The Routing Engine is an Intel-based Peripheral Component Interconnect (PCI) platform that runs Junos OS. Software processes that run on the Routing Engine maintain the routing tables, manage the routing protocols used on the router, control the router interfaces, control some chassis components, and provide the interface for system management and user access to the router.
The T640 router is shipped with the Junos OS preinstalled and ready to be configured when the T640 router is powered on. There are three copies of the software: one on a CompactFlash card in the Routing Engine, one on a rotating hard disk in the Routing Engine, and one on a PC Card that can be inserted into the slot in the Routing Engine faceplate.
You can install one or two Routing Engines in the router. The Routing Engines install into the upper rear of the chassis in the slots labeled RE0 and RE1. Each Routing Engine requires a T-CB to be installed in the adjacent slot. RE0 installs below CB0, and RE1 installs above CB1. A Routing Engine does not power up without a control board present in the adjacent slot.
 | Note: If two Routing Engines are installed, they must both be the same hardware model. |
If two Routing Engines are installed, one functions as the master and the other acts as the backup. If the master Routing Engine fails or is removed, and the backup is configured appropriately, the backup takes over as the master. If the host system is redundant, the backup Routing Engine is hot-removable and hot-insertable, but the master Routing Engine is hot-pluggable. A Routing Engine that is not redundant requires that you power down the router before replacement.
| Note: For specific information about Routing Engine components (for example, the amount of DRAM), issue the show chassis routing-engine command. |
The ports for connecting the Routing Engine to external management devices are located on the Connector Interface Panel (CIP). The CIP has three ports for each host subsystem:
- 10/100-Mbps Ethernet port for connecting to a management network
- One asynchronous serial port for connecting to a console
- One asynchronous serial port for connecting to a modem or other auxiliary device
