I have been having the same issue for the last 2 months. This was about the same time I changed my satellite provider (in Australia) and went onto the NBN satellite service - so naturally I thought that was to blame. I have fiddled around with routers and settings and the problem seems intermittant. Last week I managed to stay in SL for over an hour while I conducted some training (I work for a University that has a presence in SL) - but this week it's back to crashing every ten minutes.
This is seriously affecting my ability to do my work in SL. I have a brand new laptop, so that is not the problem. I know SL is not meant to work successfully with satellite sytems, but the fact is I have been working in SL since 2009 and while the voice etc doesn't always work well, I have not had these crashing issues.
I am wondering if rolling back to a previous version will help?
I am at my wits end and have been onto my ISP constantly as I thought it was my network service. I just would love some clarification about why this is happening and if I can do anything at all about it.