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. >
That sounds like typical asymmetric cable modem connection. > 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. > Its hard to tell if that problem was on the server end or some router between the local and remote system. > 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. > This would imply the Nashua site is OK. > 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. > Before paying for a tech to go to the Bedford site, I would try a *short* flood ping to the ISP's first advertised router (short = 5 seconds) and see what sort of loss you get. This will tell you if the problem is in the ISP's on-site equipment (and if so, the tech can diagnose it). Then try pinging to the first router outside of the ISP's network. This should tell you if the problem is inside/outside the ISP network. Armed with this info, you can then call the Bedford ISP and ask them what's going on. > 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. > Sounds to me like the Bedford ISP/Carrier needs a clue bat. --Bruce _______________________________________________ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
