Measuring network utilisation

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PlatinuM195

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Oct 30, 2007
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I'm doing a uni project and need to measure the network utilisation within an ethernet network. The network is made of multitudes of controllers connected via ethernet to 5 port switches. These switches are then connected to a larger 24 port switch.

All the switches are unmanaged. Is there any way to measure network utilisation between controllers?

I understand having a managed switch or an old network hub would assist in this, would these help?
 
a hub+pc running wireshark, etc or managed switch placed in between each switch and the larger one would solve your problem

personally i'd go with the managed switch as reading packets is not me forte
 
do not put a hub in your network!

either get a managed switch that can do port mirroring or can measure the statistics on it's own ports

or get a tap. do you have any tools that will be able to take a span and calculate the utilization? i'm sure there's some open source tool to do it out there somewhere.
 
Managed switch that supports snmp is the way to go. You can take that and use cacti/mrtg/zabbix/etc. to collect the stats and graph the traffic.
 
I'm planning to go with a hub to replace the current unmanaged switch, already have wireshark running on the PC.

I only need to measure network utilisation, not analyse particular packets or anything. Would this be ok?
 
A hub? Good god why.

Most even web managed switches will have snmp. Which you can use, as mentioned by Xipher, many tools to collect data from.
 
Wireshark would NOT be good for measuring network utilization.You want a SNMP enabled switch for viewing bandwidth utilization. Wireshark would be good for taking traffic samples and measuring the different types of packets(http, dns, irc, etc..). But even for that task, there are more appropriate tools.
 
Ok thanks guys, it's just that a hub is very cheap to source whereas a managed switch would be quite expensive.

I'm nearing the end of my research so don't have much time to formally request more equipment so I'd need to buy it myself.
 
PlatinuM195 said:
Ok thanks guys, it's just that a hub is very cheap to source whereas a managed switch would be quite expensive.

I'm nearing the end of my research so don't have much time to formally request more equipment so I'd need to buy it myself.
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A hub might be very cheap, but you're doing the test incorrectly. Whats more important, good accurate results or cheap incorrect results? Wireshark measuring network utilization is a joke, plain and simple. I hope that you have one wireshark box PER switch so you can delineate utilization from each individual sniffer session as well as account for all processing/network overhead if using a standalone box :rolleyes:

Do it the right way, once. Get a managed switch, carve out ONE vlan per unmanaged switch and dedicate two ports for that VLAN(so its like a tap, one to the access switch, one to the core). SNMP traps or polling is the best way to do something like this, mirroring traffiic will monitor and completely replicate the stream to the wireshark but I have seen inaccurate results time and time again when people try and use this method to measure bandwidth. Lockheed tried to do something like this, I put the kibosh on that really quickly(after it was unsuccessful of course).
 
Actually, a managed switch is not very expensive. All you need is a 100Mbit switch that supports Vlans and SNMP. A Cisco 2900 series switch would be perfect. Then you can do as xphil3 suggested.


Doing a quick search on ebay, I see a few in the $30 range.
 
Ok I managed to find a 16 port 10/100 managed switch supporting VLAN and SNMP for $60NZ which is about US$40. Hoping this turns out ok for my needs.
 
I plan to give PRTG a try once I get the managed switch. Already installed it on the main system.
 
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