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Help!! T1/Network Issues

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8 replies

by kate

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Alright, here's my issue...
I have a T1 line coming into the library I work for. It is a full T1, CIR 512. I am using a Cisco 1601 router, which interfaces with my internal network at 10, not 100, even though the majority of my systems are up to 100 now. My connections throughout the network seem to be very slow, and a vendor that works with me is telling me that many packets are being tagged as DE at the router even though they should not be...we are not using our full bandwidth at all, not even maxing the 512. I am trying to figure out where exactly the problem is, and not being a Comm expert, I am at a loss. I suspect the problem is with the guys at BellSouth who are the provider of the T1.
Any suggestions on how to improve or what the problem is?? If you need any more info, I will try to give it to you, but this is not my area of expertise.
Thanks.

Kate

8 replies

by radiic

Anyway you can logonto the router and do a show run for us? and post it. The DE tag refers to Discard Eligible, which is usually off by default on a Cisco router. It sounds like your interface has tag-switching ip on. A show run would tell us that.

Rad

by tech/admin

Also, remember a full T1 is 1.5 mbs well below the 10 mbs your router is showing up on the network. Also at 100 mbs for other devices on the network the T1 will always be a bottleneck... The connection on the router should not affect other deviceson the local network unless they need to communicate over the wan. What kind of traffic is crossing over the router?

by kate

It is a lot of internet traffic. We have 10 or so public access machines that are under constant use for internet access, etc.

Kate

by ted_pas7

I have a fractional T-1 at 256k which is burstable to full T-1 speed for internet access. I have 20 users with internet access and it is more than adequate for 20 users with casual surfing. I am using 15channels on a T-1 out to each of two remote branches (each channel through the TSU is 64k) and they have no difficulty with speed either. I have noticed that it does slow down the connection between clients when I allow their NIC to Auto-detect lan speed. I am using 10/100 switches and hubs and see a noticible gain in transfer rates when I force the hub-connected NIC's to 100Mbs, half duplex and the switch connected NIC's to 100Mbs, full duplex. The increase in file transfer speeds was as high as 175% of the speed achieved using Auto-detect. You may also want to use a product like Lan-Scan to determine where the bandwidth is going on your LAN. You can get a demo copy at: http://www.lanscan.com/
A simple test of your T-1 can be run when no one else is using the Internet connection by going to www.dslreports.com and running their speed test.Yuo should be able to achieve close to full T-1 to a single client with no one else on the system.
Good luck!
Ted

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