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How to send a single T1 of Internet to three offices with individual t1's

I have a ISP that runs a single T1 (with 3 logical circuits of Internet bandwidth,

circuit A -16 DS0's (1-16),

circuit B - 4 DS0's(16-19),

circuit C - 4 DS0's.

This Internet T1 runs to a centralized multiplexor that breaks up the DS0's and runs the Internet DS0's in spare interoffice DS0's runing in T1's between the multiplexor and the remote offices.

The DS0's in each office are broken out by a CSU/TSU and connected to Cisco routers. The data portion works fine sending data between office locations. The problem is that I can only turn up one logical

Internet circuit at a time, and it works great at a single remote office.

But when I turn up two offices all heck breaks loose and I get all sorts of errors. I know that the trouble is within the ISP's router.

My question is.....

1. The first router we tried was an ASEND TNT and I could not get it to work. Should the Ascend TNT do the trick?

2. What is the least cost router that will work at the ISP end and will break up a single T1 into 3 logical channelized circuits?


Will a Cisco 2500 work? and if so what WAN - CSU card is needed?


> I was up from wed at 9am until Saturday 5am attempting to fix the problem.


> Any help would be great!

VIP Purple

Re: How to send a single T1 of Internet to three offices with in


for channelized T1 circuits a 2610 would be the minimum.

What happens exactly when you turn up your second office ? Do you have no Internet connectivity at all then ? This sounds like it could be a routing problem - is it possible to post the configs of two of the routers of your offices ? Which routing protocol are you running with your ISP ?



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