I had a similar problem, constant disconnects when engaging in battle. Mostly on the slaves but on few occasions my main would DC. I had around 500ms latency, but it spiked upwards over 2500ms, sometimes even much higher on the slaves. Turned out my (onboard) NIC was broken, so I had to replace the mobo.

Also, you running the latest version of Jamba? Check the advanced options, there is a setting that throttles communications, try turning it on.