Company's slow internet connection

fifrasco

For those experienced network engineers....When working for a company(enterprise level), how do you tackle the issue with having slow internet connectivity for users. What's your troubleshooting methods? Do you check processors cpu on WAN routers, or Core switches? Obviously there is always going to be a top talkers, but how do YOU determine if its just someone taking up most of the bandwidth or an actual problem with the ISP circuit?

I would like to know how most people would troubleshoot this problem.

Thanks

RomBUS

Is this occurring for a single user or happening on a grand scale here? Perhaps a particular floor?

fifrasco

Grand scale...Entire building

Dieg0M

When there is slowness for a flow, you should troubleshoot the problem hop by hop. First determine if the routing is clean (make sure there are no routing loops (asynchronous routing is ok in most cases but can cause issues for some applications or if you have stateful firewalls). Check hop by hop if you are having any input/output errors on the interfaces or CPU problems on the switch/routers.
If you don't see any of these problems (all clean) up to the WAN, it will sometimes be a problem with the Proxies or Load Balancers in path of the flow. Check the logs for these.
If you still didnt find the issue, make sure the domain is not slow through another ISP. If it is not slow through another ISP, then call your provider.

Heero

Figure out if it is just one person or one group of people, or if it is everyone. If it's everyone, start looking at utilization data for the connections and look at resource usage on your routers/firewalls to make sure they aren't bogging down. If it's a single person or a group of people, then you have to look internally. Investigate everything that the person or group doesn't share in common with other people/groups that aren't experiencing the problem.

You should be doing netflow on all your internet traffic so you should have decent graphs showing what is using of your Internet pipes. You might also want to set your SNMP box to poll interface utilization based on the 5 sec average and pull that every 30 seconds or so to get a more granular look at the utilization at exact points in time.