Network slowness

[itstaff2011]

Description of the issue:

My company experiences network slowness, (3000ms+ ping times). It typically happens on only Monday mornings between 8am and 11am(times are not exact). But in the last 2 weeks it seems to happen other days, even as I type this, we are experiencing 1000ms+ ping times. We have 2 bonded T1s coming into the building which connects to a Cisco 2800 router and that connects to a SonicWall firewall. I have had SonicWall look at the FW config and logs multiple times but nothing looks "odd". We have had our ISP remote into the 2800 router, during the slowness, and ping out with normal responses (~30ms) and showing we are only using about 25% of our bandwidth. I have connected directly to the lan port on the FW and I receive normal responses but within 3-5 minutes of plugging the core switch back in, the slowness reappears. The issues first appeared somewhere around the time when we replaced all of our switches, which was about 3 months ago.

What we are looking for:

Basically, we are looking for some way of being able to monitor our network traffic during this period of slowness to determine what is causing the issue.

If you need more detail to be able to help, let us know and we will get it!

Any ideas or thoughts will be appreciated.

Thank you in advance for your help!

 

[VinceWhirlwind]

You'll have to explain this bit:
"We put a switch between the firewall and the router and ping times were normal. We move it back between the FW and it slows back down. "
*EXACTLY* what is the path of your ping and *EXACTLY* which devices sit in the path of your ping when it is slow?

Also, I don't understand why you would write:
"seems that something on our network is hogging bandwidth " when you've just said you are not reaching your limit. What bandwidth do you think is being exceeded?

When you write
"utilization on the switches is low (usually around 20%). "
what are you referring to? Memory, CPU, interface traffic,...?

 

[itstaff2011]

We plugged an unmanaged switch between the firewall and the internet router. Then we plugged a PC into that switch and the ping times are around 30ms. When we move the PC back inside the network the ping times went back to 1500ms+. When we ping we would ping

http://www.google.com.

The reason why I say "it seems that something on our network is hogging bandwidth" is because, like I mentioned, when the PC is behind our firewall(inside our network) the pings are slow and when it is outside our firewall, the pings are slow. I dont know if it clears things for you.

We have a gigabit backbone and our firewall cpu utilization was usually around 14% and the switch cpu utilization was around 20% during the "slow" times. The switch memory utilization is usually around 30%. None of the switch port utilization looked very high. I'm not sure % wise but it was somewhere around a few hundred MB at the highest.

I understand this doesn't make much sense but this is what I've been dealing with...

So, I really am not sure. I dont think any bandwidth is really being hogged but obviously something is causing us to have delayed ping times.

I know thats not much for you to go on, but the main thing we are looking for, is something to be able to monitor our network traffic so we can find what is happening.

If you need any other clarification, I will do my best to not confuse you more

Thanks for the help so far.