Slow network : Please advice

[harrysmoore]

Hello everyone , 

I am fairly new to cisco but I have an issue - we have four layer 2 switch connected to 2 layer3 switch . Plus 4 wireless access points controlled by an access point controller . 

But the problem is - when ever everyone is connected - the network goes sooooo slow ( we have about 40 people connected ) the internet goes slow and even the network ) 

We have 2Mbps/2Mbps internet connection. 

Please can someone direct me to what I can do to ehance my network ? Or Mayb there are some configuration I need to change . 

Please advice . Thanks guys 

[Charles Hill]

Check for speed/duplex mismatch on interface connecting to Internet, switch to switch and switchports directly connected to pcs.

look for Input errors on interfaces.

verify correct cabling is used between switches.

or mdix is working properly.

This is a start.

Hope this helps

[harrysmoore]

Thank you for your reply.

The thing is , internet is quite expensive at my location – we are not yet looking to upgrade(But the manager thinks there's something wrong  - saying  2mb is really enough because he is paying loads)

Anyways I just want to fully cover my ends that its nothing technical before I bounce on him.

We use a cyberoam UTM here connected to a Layer 3 Switch (Please see below diagram).We also have our wireless access point connected to some of the layer 2 switches.

[Joseph W. Doherty]

Are your L3 switches running as L2 or L3?

Is the UTM performing interior L2 or L3?

[harrysmoore]

Yes,The L3 Switches are runing as L3

(I dont fully understand what you mean by "UTM perfoming interor L2 or L3") 

But NAT is configured on the UTM.

[Joseph W. Doherty]

I see connections from each L3 switch to the UTM, but not to each other.  I.e. UTM could be a possible bottleneck for LAN performance.

[Joseph W. Doherty]

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Posting

2 Mbps Internet bandwidth shared by 40 users?  Well, your mileage might vary, but now a days, even just one user can often pretty easily saturate that much Internet bandwidth.

40 users, though, should be pretty easy to handle on most modern LANs.  If you're also having LAN performance problems, we would need a much better description of your LAN environment to (somewhat) verify your topology and/or equipment isn't likely to be a problem.

[devils_advocate]

2Mbps is pretty slow for most homes nowadays, let alone an office network shared by 40 people!

Watching a youtube video could eat most of that from a single user.

If there is no option to upgrade your bandwidth, you may need to look at implementing some bandwidth management. 

If you think there may be an issue with the network itself, post back the configuration of the switch (es) and we can see if there are any obvious configuration issues.