Wayne; there are a few options that you have here. The simplest depends on a few things.

Currently with the 4 t-1s are they multiplexed as one connection to your ISP or are they muliple connections that are load balanced with your routing protocol?

If so, what's your routing protocol?

Are you running a dynamic protocol like EIGRP, OSPF or RIP that may be handling your load balancing across the 4 T-1s?

Oh; are they load balanced at all? What I'm getting at is do they ever max out?

If they don't and you're using the default queueing method (First in first out - FIFO) then it might be as simple as turning on weighted fair queueing. That gives lower bandwidth traffic a higher priority than high bandwidth. At 128K there is some risk that the Voice traffic could get downgraded which of course would be bad.

In that case you can do custom queueing; custom queueing uses "buckets" (queuing filters) and I think the simplest thing to try first would be to give your VoIP traffic #1 precedence and anything else would match #2. All you need to do is likely ID the ports that your VoIP is using and put that in the first queue list, if you wanted you could probably also use (or use instead) the IP address of your VoIP termination point in your office. Hosts destined for that box would have a higher priority than the rest.

Let me know if you need some help; I'm walking distance after all. :D

Wayne, why aren't you just asking your ISP to bump up the bandwidth on your DSL? Are you a long way from your telco's local closet?

Wayne-

This might be of use to you:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt4/index.htm

Gets pretty technical pretty fast, but you should be able to do what you need to using Class-Based shaping.

Of course, the exact implementation depends on the answers to Mikesters' questions, but this is usually how Cisco pulls this off.

Personally, I'd get a professional Cisco guy in to do this... it's REALLY easy to mess up if you don't know what you're doing, and some of the subtleties can be tricky to get right if you're not familiar with the configs. Shouldn't take him/her more than an hour or so to figure out what you have, figure out what you need, config it, then test it, and it should be doable "hot" or "live", without requiring any real downtime.

$0.02

So you have things setup like this?

isp~~~~4T1~~~~PP3640-----ethernet to sonicwall

so if you are wanting to set aside some bandwidth on the T1s it's only really going to help for voice going out from the 3640 to the isp. Or will the ISP work with you to get both ends of the link setup similarly?

Wayne, you can also avoid the QoS business by limiting the bandwidth used by certain IP addresses on a Cisco router by using the 'rate-limit' command. You specify the addresses to be limited with an access-list. You could use this to limit the bandwidth used by your non-VOIP addresses, leaving some left over for VOIP.

Don't know how well you can get around in the IOS, but the command in global config mode would look something like:

rate-limit input access-group 101 8000000 375000 500000 conform-action transmit exceed-action drop

Access-group 101 refers to access-list 101, which would contain your addresses to be limited. The numbers represent average and burst rates and can be tweaked as you like.

Let me know if you have more questions,

ianc