I am told that there are network latency issues. What could be the possible causes?

[ranjipremandrewp]

I am told that there are network latency issues. What could be the possible causes? What are all the paramaeteres that I should be checking?

[Marvin Rhoads]

1. Get more information. Is the problem new? When did is start happening? Is it experienced by all users or only a subset? Is it for all services or only a subset. ...etc.

2. Verify the problem is indeed on your network. The simplest way is to traceroute from the network devices that is the default gateway to the address of the service customers are reporting slow access to.

3. With more information look at the data you have gathered and if there does indeed appear to be network slowness, look more closely at the problem links. Examine device logs and interface status to look for recurring log events indicating a problem or interfaces issues (CRC errors, packet drops etc.).

4. Is there a WAN involved? If so, check link utilization to the extent that you can.

[devils_advocate]

You need to narrow down where the latency is occuring. Narrowing down where the issue is occuring is key otherwise you will have too much information to look through.

As Marvin suggested, a traceroute is probably the easiest first step in doing this.

Do you use any form of automated network monitoring such as Solarwinds? We used this at my previous job and it was a great tool.