Zyxel vs Comtrend (bonded Fusion) QoS

[profeti]

We have bonded Fusion service with the Comtrend NexusLink 5631 modem/router and are experiencing virtually a complete loss of downstream when uploading files of any significant size. Apparently, this is due to ACK packets not getting upstream priority. Even though it doesn't appear that the upstream is being saturated, the transfer rate during upload is only about 200KB/s and we're getting 1.6-2.0Mbps upstream on the line. The Comtrend QoS is pretty much useless, and by "pretty much" I mean completely, since enabling it kills connectivity altogether. I talked to support yesterday, super friendly and helpful as usual, but we weren't able to fix this problem. She suggested trying the Zyxel modem, however, loaners weren't available and the Comtrend is a couple of months out of warranty so we'd have to buy Zyxel to try it out. Before doing that I was hoping to get some feedback on the probability of the Zyxel actually solving the problem to avoid the expense and hassle of having to return it...

[dane]

FYI, around October or November, I anticipate we will be offering a new Pace gateway for bonded customers. It will be a rental option, and might be worth considering.

[cduran]

Unless I am misreading your message it does sound like you are saturating the upstream portion of your connection. 200 KB/s is roughly 1.6 Mbps. If you are sync'd at 2 Mbps upstream, 1.6-1.7 is the top end transfer rate you'll see (due to protocol overhead).

I don't believe a Zyxel will be of any help here. Many programs used to upload files have an option to limit upstream transfer rate, is that an option for you in this case?

[dane]

I think he is looking for ACK prioritization.

[profeti]

Prioritization is the thing. Throttling doesn't really work for us other than as a temporary workaround. Even prioritization would be short term solution, what we really need is more bandwidth. If only there were an ISP that provided Gigabit fiber at reasonable rates...

I've got a call in to Comcast to add cable as a supplement, but that's overpriced (especially for business customers) and, well, it's Comcast. Also considering adding a second bonded Fusion, though that would be more attractive if dry loop was an option.

Re the gateways: Apparently the Zyxel and Comtrend are running essentially the same firmware, and though it seems they should be capable of doing ACK prioritization there's no info on how to configure either. Will the Pace be any different? Should we just install a full featured router and set the Comtrend to bridge mode?