Client IP and Redundancy

[pounder]

I have a couple redundant upstream links on one of my modules, and it seems to be connecting and reporting everything ok.

Can I get some factual information on the scenarios when this would or wouldn't work and what the delays would be ?

- does it use a held open tcp stream so once a connection is established it would stay on one path so the client ip with respect to the server would be the same ?

- does the server care if the ip changes between each contact ? (eg is the state held by mac of the device in the request alone, or is that matched up with last seen ip in any way ?)

- what kind of lag is there between a lost contact reported and when contact is actually lost ?

- is tcp or udp communication used to the servers ?

- if a connection is broken how long till the modules tries again to establish contact ?

I am thinking of whats needed to make things work in scenarios where internet might go down but you have a cellular based modem for backup and how you would detect that and fail over, my setup is just loadbalanced with sticky routes so both are up all the time and I don't know which route any particular packet uses.