On Thu, 2008-07-10 at 19:36 -0400, Alex Hewitt wrote: > I have clients with an interesting network problem. One location in > Bedford New Hampshire using a fractionated T1 has routinely been > transmitting studies to an office in Nashua New Hampshire. There have > been no problems with this for at least 18 months. However recently > (about a week ago), the transmissions suddenly became slow, really slow. > A transmission that was taking around 10 minutes suddenly jumped to 2-3 > hours. The customer in Bedford New Hampshire is using One > Communications. So far I haven't asked them to look at this problem > because I've been trying to clarify it. The office in Nashua has > Comcast business class service with a static IP address. > > Here's where it gets interesting. I had the Bedford client transmit the > data to my system in Manchester New Hampshire. I have Comcast > residential service. The data usually takes about 8 minutes to arrive at > my location. I then send the data to the Nashua office and it typically > takes 25-30 minutes. The payload is a collection of images that are > typically between 65 and 70 MB. > > Today Comcast at the request of the customer sent someone on site to the > Nashua site. The tech did some speed tests using the DSLReports > Speakeasy test suite. He was getting 20 mbs down, 3+ mbs up which is > pretty decent. For the fun of it I had him download a 47 MB antivirus > program. His first try was ridiculous telling him it was going to take 4 > + hours. I had him break the connection and try again and this time the > download took around a minute. > > And it gets more interesting...another client in Salem New Hampshire > needed to send their data to the Nashua site (they use Verizon DSL). It > arrived in about 8 minutes. > > So my Comcast connection which is fairly decent is taking a half hour to > send 65-70 MB to the Nashua site. The Salem site is taking 8 minutes for > something approximately the same size and the Bedford site is taking > several hours. > > Traceroute doesn't show much interesting - it craps out after the first > 5 hops. Pinging (standard payload) from my office to the Nashua site is > averaging less than 20 ms. One odd thing is that when I'm in the process > of sending data to the Nashua site my pings jump up to 650 - 800 ms. > > The Comcast tech was happy to conclude that the Nashua site was working > properly. They checked transmission levels, noise and of course the guy > downloaded some files and ran the Speakeasy speed tests and all of that > looked good. > > Any ideas how to proceed on a problem like this? Currently I'm having > the customer transmit their data to me and then I re-transmit because my > connection although slow is probably 4 or 5 times faster than theirs. > > -Alex > >
A few more bits of information - I replaced the router in the Nashua office (Netgear FVS 114) with a new identically configured model. The download performance and speed tests were run with the Netgear router in place (all good). I disconnected the router from the cable modem and hooked the Mac that runs the client application directly to the cable modem. Again all download tests look normal. I replaced the original Mac with a newer model. The old system was a Mac Mini with 1 GB of Ram and a G4 CPU. The replacement model was a dual core Intel based Mini with 2 GB of Ram. The new system is definitely snappier but doesn't affect the problem at all. -Alex > > > _______________________________________________ > gnhlug-discuss mailing list > gnhlug-discuss@mail.gnhlug.org > http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ _______________________________________________ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
