Understanding network load monitering

[cyberpete]

I have a Cisco lan environment with 100mb fullduplex (ie single collision domain) network. I have a single PC collecting video images from various security cameras cameras. I have 5 client PC's which use 3 mb/sec of bandwidth whilst accessing the moving images (which is 7x24hours).

Can I assume that if each client is on a full duplex / 100MB connection then the total bandwidth being consumed is 3MB/100MB per connection. IE total bandwidth available to the 5 PC's via fastethernet is in effect - 500MB (5x100mb/sec) and therefore the overhead is 15mb/sec (5 PC's x 3mb/sec). In other words the 5 pcs have a true collective bandwidth under fastethernet of 500MB/sec (5x100).

Boss is concerned that we are going to eat 15/100MB/sec but I dont think so.

Notes, queires & answers welcomed.Thanks.

Peter@it-123.co.uk

[johansens]

Hi there,

It really depends.. If you have the server and clients all connected to one single switch and the client/server traffic is of unicast-type, there should be no problem at all.

If you have the server connected to one switch and the clients to another switch, then the traffic will have to cross between the switches. If your inter-switch link is a single 100BaseTX connection, you will take the total of 15Mbps of this 100Mbps link.

You really will have to see exactly where the traffic flows and where/what the bottlenecks are.

A Cisco switch of newer make have wirespeed at all ports, so there should really not be any problem when all the traffic is contained in one switch.

If the server is broadcasting the traffic, this will get out to every active port in the same broadcast domain (ie. VLAN). If it's multicasting and you don't have any igmp snooping on the switch, it'll behave similar to a broadcast (go to all ports..).