Traffic shaping for T1

[jarmentrout]

We currently have one T1 for internet access for the entire network. At times traffic can get heavy and this causes our latency to increase to around 200-300ms. If just one user is downloading a file and using all available bandwidth it causes our ping times to go up, which is not good for VOIP or VPN tunnels.

Our first router is a 1600 with T1 WIC. and then goes to PIX and 3725.

Any suggestions on what I could do, could I rate limit web traffic?

[tcordier]

Hi,

you could configure quality of service on the 1600, or the 3725, in order to prioritize VoIP or VPN traffic over http traffic but there is one problem: any prioritization you will achieve through this only applies to outbound traffic, while the problem you describe is caused by inbound (coming from Internet) traffic. In your situation you can not control, or prioritize, the inbound traffic. Since for traffic such as downloads the inbound traffic is much more important compared to the outbound traffic, you only can act upon a negligible part of the problem. Some solutions I would investigate rather than rate limiting the outbound traffic are:

- ask your ISP to apply quality of service or prioritzations to the inbound traffic (coming from the Internet to you),

- identify the traffic causing the problem, and solve the specific problem. If, e.g., the problem is caused by web browsing, you could install a local cache,

- upgrade, and buy your way out of the problem :-).

hth