References to Catalyst switches encompass Catalyst 2900/5000, 4000, 5500, 6000 and 6500 series switches. They do not encompass Catalyst 1800, 1900, 2600, 2800, 2900XL, 3500, and 3900 switches. The distinction is important because Cat 2900/5000, etc. switches run code different then the other switches and routers. Because Catalyst 2900XL and 3500XL switches run IOS, answers involving IOS apply to these switches. Please also note that some of the switches that were not current IOS at the time this book was written may be updated to run IOS code.
To assist you in locating FAQs of particular interest to you, Table 19-1 lists all the FAQs covered in this chapter, along with their page references.
Table 19-1. Frequently Asked Questions
| FAQ |
| General Network Management |
| How do I configure logging to a syslog server? |
| How do I configure a RMON threshold? |
| What threshold values should I use? |
| How can I track whether a router or switch disappears from the network? |
| How do I graph data that requires a calculation? |
| How can I enable or disable certain kinds of traps? |
| How can I collect information that is available in a show command but not through SNMP? |
| How can I force a router to consistently provide the same source IP address for any traps or syslog messages? |
| Why can't I collect RMON statistics from a switch? |
| General Interface Management |
| How do I collect CPU utilization? |
| Why is IP SNMP causing high CPU utilization? |
| How do I collect free and largest block of contiguous memory? |
| How do I collect Catalyst switch backplane utilization? |
| How can I measure router or switch health? |
| How do I measure the ratio of Buffer Hits to Misses? |
| How do I measure the ratio of process-switched packets to total packets? |
| How can I avoid a device appearing to be down if a single managed interface goes down? |
| How can I track when a power supply dies or a redundant supply changes state? |
| How do I track when a Cisco device reloads and determine the reload reason? |
| Can MIB II ifTable variables (such as ifInOctets) be collected from sub-interfaces? |
| How can I collect interface utilization and monitor it over time? |
| How can I measure utilization for IOS sub-interfaces? |
| How do I collect interface utilization from high-speed interfaces such as ATM and gigabit Ethernet? |
| How do I disable/enable traps for specific router or switch ports? |
| Why is my interface utilization greater than 100%? |
| How can I measure interface health? |
| How can I detect if an interface goes down? |
| FAQ |
| How can I determine the bandwidth of an interface or sub-interface? |
| How do I track the number of broadcasts received on a particular interface? |
| How do I clear device SNMP counters? |
| How can I collect interface information when the ifIndex always change for interfaces? |
| VLAN/Spanning Tree |
| How do I collect VLAN utilization? |
| How can I track spanning tree topology changes? |
| Why do I see the spanning tree for only one VLAN with SNMP? |
| Frame Relay |
| How can I measure the number of Frame Relay drops that occur? |
| How do I measure Frame Relay circuit utilization? |
| How can I detect whether a Frame Relay PVC changes state? |
| ATM |
| How do I get ATM sub-interface traffic statistics? |
| Dial/Modem/ISDN |
| How can I track rejected modem and ISDN calls? |
| How can I track calls that are rejected due to lack of B channels or available modems? |
| How can I gather the equivalent of a show dialer command using SNMP? |
