Slow T1 connection

Question

I have a dimension 4550, that has a Intel Pro/100VE Network Connection in it.  We have a T1 connection in our office that is performing rather slowly.  The internet connection speed is pretty good, but the connection to our other office via the T1 is slow.  Is the network adapter that I have adequate enough for a T1 connection, and what else could I check?

fireberd · Answer

The potential problems are many on something like this.  I doubt that it's the NIC card, even if it's only a 10Mb card (and most are 10/100) as that's 10 times faster than your T1 link.   However, is the T1 link full T1 bothways or only T1 on the downlink (receive)?  That's the first thing to determine.  Many links are 'high speed' on the receive side but only a partial T1 (sometimes only one DS0 on the uplink  - a 'DS0' is 64Kb)   Second the 'connection to our other office' is a totally separate issue. Your connect to your ISP is only one part of the entire link.  It may have the full T1 but after it leaves the ISP and goes to the link for your other office it is a separate telecommunications link.  You need to check the link speed of the other office and see if it's performing up to specs.  Then there is the interconnections between the two offices T1's which can be another bottleneck.   Have you checked with the T1 provider(s) and had them verify the links are operating at 'published' speeds?   I know this is a lot to consider but being a retired LAN/WAN Network Manager I dealt with data link issues and with Telcos on a daily basis for 23 years.  Unfortunately you may need to bring in a network engineer to determine what your problems are - the telco (or whoever is your data link provider) may not be much help.

skirk1 · Answer

We did have our provider check and both lines are operating at the correct speed.  Here is an example of what is happening.  We are an architectural firm, and deal with Cad files every day.  Example file is say 2 meg in size.  You can open that file in the other office from the server, it will open in a matter of seconds.  Trying to open that same file across the T1 line from this office will take up to 3 min.

fireberd · Answer

Where is the server located? At your location or the other office's location (or some 3rd party location)?

If the server is in a remote location does other server functions take as long or is it only the CAD files?

As I noted before having the provider check the lines does not always really tell you the condition of them. I've worked with Telco's too long (grin).

skirk1 · Answer

The server is located in the other office its about 300 miles from where I am. Other functions seem to be about the same as the CAD files. Of course the other files are not near as big, but on a percentage basis the time is about the same. The server is built to run about 100 computers from it. Currently there are only about 35 running off it. I am using a cisco 1700 router that is connected to my T1 Modem. Then from the router it goes into a Dell 2608 power connect hub, and out to the five computers in this office. Is there anything wrong with that setup. Also is the router necessary, or can the T1 line plug straight to the hub. I am a little in the dark on understanding that area.

fireberd · Answer

Eliminating equipment would be a good troubleshooting step.  Can you connect a PC directly to the T1 modem or do you have to go at least go through the Cisco router?  I'd bypass whatever I could and try it to see if a device is causing it.  Have you called Cisco to see if it's the culprit.  My website host was having a problem with slow access and it turned out to be a Cisco router problem and they got a software patch from Cisco to fix it.

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Slow T1 connection

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