This chapter identified the key hardware and environmental characteristics of the routers and Catalyst switches. We looked at performance management of the hardware by identifying the types of cards and the positioning of the cards in the chassis and related it to the architecture of the device. We looked at specific data points that could affect the hardware performance, such as hardware version and microcode version. Actively updating your inventory through polling the recommended MIBs after a change management window can greatly increase your network's stability and your knowledge of the network.
We looked at how to monitor faults in the network relating to hardware and environmental characteristics. One thing unique about error/fault monitoring of these characteristics is that you depend more on syslog and SNMP trap messages than on actively polling the MIB variables. With so much hardware out there in the network and a low percentage of environmental failures, it makes sense to let the device tell you when an issue arises instead of always asking the device "Are you OK?" just to get a response of "Yes, I'm OK." Relying on syslog and trap messages also reduces the amount of overhead on the network compared to polling these characteristics. The following chapters do not lend themselves to this kind of methodology. Instead, you'll find that most of the chapters in Part 2 of this book concern some kind of active polling.