Balance 380 does not attain full throughput on WAN port

I have a Balance 380 connected to an ISP that offers me 100mbps. However, the 380 will not give above 50mbps.

Furthermore, and I’m not sure how this relates to the issue, but the 380 is set to auto-negotiate and the ISP is set to 100 full duplex. If I change the 380 to 100 full duplex, the connection drops completely - “no cable detected”. I have tried all permutations, including setting the ISP side to auto, which also gives only 50mbps.

If I connect a Windows PC direct to the ISP and set the NIC to 100 full duplex, I can connect at 100mbps, so I know the ISP is carrying the advertised speed on their side.

Firmware is 5.4.7 build 2423

Any thoughts on what may be causing this issue?


Let’s take a look at the support.cgi page and see if there is any errors on the interface and confirm what duplex/speed the port is at first.

I see some errors and collisions on the support page, but they do no seem to be growing, so maybe they are historical errors from when we were setting the line up the first time, looks like currently the link is clean.

Receive Transmit
Packets Errors Dropped Overruns Frame Packets Errors Dropped Overruns Carrier Collisions
35325551 0 0 0 0 33895631 56009 0 0 56009 434455

I have discovered that I can get it to establish a link to the ISP box at fixed 100mbps fd if I uncheck the “advertise speed” box. This is replicable, but with the following bit of weirdness: it only works if I set it while unchecking “advertise speed” in the support page and then applying changes in the dashboard. If I uncheck “advertise speed” from within the Network Settings page and then apply the changes, the connection breaks.

Maybe the speed advertising is the issue, although I do not really understand what that means and why it matters whether I check it from the support page vs. setting it from the Network Settings page.

Edit: I am still not getting 100mbps from the ISP.


Hi Ed, just want to confirm if this is a contended service from the ISP or a guaranteed 100Mbps? The reason I ask is because one of my home connections is a DOCSIS 3 cable modem with a marketed rate of up to 100Mbps, and I rarely get close to that. Most often I see 40-60Mbps average, with an occasional spike to 90 and dips as low as 20. S/N ratio is very good on the line, just very contended.

Anyways, can you try the same connection on the other WAN ports of the 380 and see if you get similar results? We could also try hooking up a dumb switch in between the modem and WAN port to see what happens. The idea here is to see if there are any Ethernet port negotiation issues going on.

Well, I do get 40-60mbps, so you may be right that it’s just a contention thing. Of course when they run an iperf direct to their site, with modified window sizes, then it flies at 90mbps … so they are quick to say “the problem is on your side”. Not so sure I buy that.

I’ll try the idea of a dumb switch between the modem and wan port and see what happens.

Thanks again.