High Availability. (Maybe OT)

[Kevin Welch]

I am trying to figure out how to impliment a redundant network design.  The problem I keep running into is the connection to the server.  I can provide Access redundancy through the use of two switches.  I can provide some level of server redundancy via the use of 2 NICs or 2 Servers.  The problem is how to provide application layer redundancy.  I have been able to prove the network itself is redundant, but connectivity to servers seems to be where I am having trouble with my studies.   From my understanding I cannot do etherchannel accross switches, and more over, I remember that etherchannel does not provide redundancy because if one link goes down the whole channel goes down.  Please correct me if this is wrong.    Example:   Realizing that the expectation that a server stay up all the time would still be a single point of failure.  In the event of a network failure on a switch, how do I provide network access to the Server.    Proposed is to connect the server via a second NIC or second port on a dual or quad NIC to a secondary access switch.    Problem, maintaing the same layer 3 address accross both switches in the advent that one link should fail, the server maintains reachability.   Giving that in this case I would be talking about a solaris system, I have thought about using simple scripts to watch for the interface to go down and reconfigure.  I am curious if anyone knows of any hardware/software solutions for doing this?   I am guessing that I am not the first person to ask for something like this.   -- Kevin