At 06:36 PM 1/25/02, Doug Korell wrote: >I have checked individual switches and routers for utilization before but >when asked what the average utilization of an entire network (mainly LAN) >is, what exactly makes up this figure? I am working on getting a packet >sniffer which I know will help take all the variables and give me an answer >but is there a way to do it without one? How about SNMP queries? If anyone >can help explain this or knows of a good website, please let me know. Thanks.
That's a rather old-fashioned question. It used to make sense on a shared LAN. You could put a Sniffer or RMON Probe in a shared hub and get a measurement of how much of the overall, shared 10-Mbps capacity was in use on the LAN. In these days of microsegmented, switched networks, you can't do that easily. You can only monitor the switch ports that you mirror. Each switch port provides full capacity, usually 100-Mbps full duplex. (You would have to know if that's true for your network.) Overall capacity is the number of ports times the speed. Overall utilization would be the aggregate of each port utilization divided by the overall capacity, I guess. (But people don't actually tend to make that calculation.) Another capacity issue is the backplane speed of the switches and routers in use. That could actually be more of a bottleneck than overall LAN capacity. Did a pointy-haired boss type ask you to make this measurement? I'm afraid you might have to explain that it doesn't make sense. Work with them to specify which individual LAN ports need monitoring, rather than trying to find an overall number. The ports that you should monitor are any ones that aggregate traffic. Check the utilization on trunk lines and links that go to mission-critical servers. Also, check utilization on an end-user port while doing some typical processes, including logging into the network. It might also make sense to check other performance metrics such as response time. Hopefully others will respond too in case I have a blind spot with regards to this, but my initial thought is that this is not the right performance measurement to be considering for a modern LAN. Priscilla ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=33267&t=33256 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
