Hi and thanks for looking.

We have a main site in the South East of the UK and a satellite branch in Birmingham (we moved offices 4 months ago to a new site). We have a Multisite WAN with our ISP, we run a 30mb Fiber at our main site and bonded dsl in Birmingham (10mb circuit). We run a DB server (Filemaker) at the main office which our satellite offices connect to over the WAN. Birmingham branch experiences lag and incerdibly slow speeds when doings lookups or finds or when copying data from our fileserver and all ping tests I run from the 3 machines up there (two macs and a win 7 machine) get 12% or more packet loss when pinging our router or DB server in the main office, however our ISP tells me they cannot replicate this from the router.. We have replaced the CAT5 cabling at the branch and our ISP sent an engineer to check the other hardware wasn't to blame which I'm told is all functioning fine.

Getting super frustrated now and would like a fresh opinion on the possible reasoning behind this. Think I've included all the details but feel free to ask anymore questions!!

Thanks for looking.


1st thing i would do is disconnect all internal lan devices. Plug a single system directly into your DSL drop (or into your DSL modem... not sure what type you have).

You should have 1 machine online. There's a linux tool called 'mtr' that will trace along a path and point out drops and delays along the path. If you have a mac, I would imagine there is a similiar util on there.

Point is, you should 1st eliminate all internal systems from the mix and run your tests to see if you can replicate the packet loss.

The following may be of interest:
Packet loss

Here are a few ideas.

Possible issue 1:
Packet loss due to network flooding. This could be caused by a bad network card, a virus, etc.

Unhook all computers except for one, and test for packet loss. Repeat for the other two computers.

Repeat test using a clean computer--one that has a newly installed OS, or one that is known to work from another site--this will eliminate any computer hardware issues and the possibility of a virus/malware. Connect this computer to the cable from one of the other computers.

Possible Issue 2: Noise/interference on/in the cabling from the environment (such as fluorescent lighting, or other electro-magnetic interference)

Using clean computer, repeat test close to the router, using a 1-2 m cable to connect to the router. Disconnect all other cables at the router. Test for packet loss again.

Thanks for your comments guys, much appreciated. I'll run the tests you've suggested.

Many thanks.


In the end I replaced all the cabling etc at site and that made no difference. A Cisco guy at our ISP ended up getting invoved and said that the Router at our HQ wasn't beefy enough to handle the traffic.. Got it upgraded for free and problem solved.. Thanks again for your input.