redundant backbone connections

[mastodonic]

I have two internet backbone connections, each connected to it's own firewall (Nokia IP330s). Only 1 connection is needed at a time (however, using both is fine if it's easy to configure). How would I go about configuring a switch or something to provide this redundancy? I have some extra switches to spare (Cisco 2950s). I tried looking into trunking, and am not sure how to configure it. I also looked into spanning tree, and I know it prevents loops, but I'm not sure if it works for this.
Someone please help, it's urgent.

Thanks in advance.

 

[baddos]

Two switches, two routers, two firewalls. Have the routers and firewalls on their own switch, and maybe have the switches connected together.

Don't really know the specifics of your network though.

 

[davemiller]

Simply you can have two routed connections to the internet from the same lan - nothing special. It would be a problem if it were a layer 2 connection, but this would be a layer three connection so it will be fine. The routing protocol should assess either route and adjust the load/route according to the 'cost'.