[Users] how to refresh REGISTER state when restarting redundant proxy

[Juha Heinanen]

Klaus Darilion writes:

 > > it would be interesting to read that paper, but i guess it is not freely
 > > available.  so far i have not seen  any solution that would do two
 > > the things at the same time: balance load and be resilient.
 
 > http://www.google.com/search?q=Failover%2C+load+sharing+and+server+architecture+in+SIP+telephony

thanks klaus for the pointer.  

i briefly looked at the proposed solution in figure 12 and didn't find
anything about nat keepalive pinging.  which of the proxies does that or
does the solution assume that UAs are not behind nats?

-- juha