Figure 262: Ssb Component; Figure 263: M20 Router Ssb Location - Juniper M Series Monitoring And Troubleshooting Manual

Hide thumbs Also See for M Series:

Table of Contents

lookup, the Internet Processor ASIC informs the midplane of the forwarding decision,

and the midplane forwards the decision to the appropriate outgoing interface.

System component monitoring—The SSB monitors other system components for

failure and alarm conditions. It collects statistics from all sensors in the system and

relays them to the Routing Engine, which sets the appropriate alarm. For example, if

a temperature sensor exceeds the first internally defined threshold, the Routing Engine

issues a "high temp" alarm. If the sensor exceeds the second threshold, the Routing

Engine initiates a system shutdown.

Exception and control packet transfer—The Internet Processor ASIC passes exception

packets to a microprocessor on the SSB, which processes almost all of them. The

remaining packets are sent to the Routing Engine for further processing. Any errors

originating in the Packet Forwarding Engine and detected by the SSB are sent to the

Routing Engine using system log messages.

FPC reset control—The SSB monitors the operation of the FPCs. If it detects errors in

an FPC, the SSB attempts to reset the FPC. After three unsuccessful resets, the SSB

takes the FPC offline and informs the Routing Engine. Other FPCs are unaffected, and

normal system operation continues.

Figure 262: SSB Component

You can install two SSBs in the M20 router. The SSBs occupy the two top slots of the

chassis. (See

Figure 263 on page

The SSB houses the Internet Processor ASIC and two Distributed Buffer Manager ASICs.

), and are installed into the midplane from the front of the

Chapter 23: Monitoring the SSB