Today I started setting up in my lab a network with redundant Cisco 2970 switches. The hosts are two HP DL145 servers with two broadcom GBe NICs. The systems are running Linux 2.6.15.1 and I have enabled bonding in the kernel as a module.
Each NIC is plugged into a different switch, and the switches are NOT connected together using ISL or any other method. For all intents they operate as single switches. Each switch is in turn connected to a switch on which my gateway is located.
I have the configuration working using mode 0 (balance-rr). Using tcpdump on the underlying slave interfaces, I can see that packets are in fact being sent out over both interfaces, and that odd sequence numbers are sent on if0 and even numbers are sent on if1. If I unplug one of the interfaces, the bonding driver marks it as down, and stops sending data on that interface. When plugged back in, data transmission is resumed. Furthermore, when using the bonding driver's arp monitoring of the default gateway, unplugging a switch from the upstream switch causes the interface connected to that switch to fail.
My question is if this is a "supported" configuration and/or if there is a better way to make this work.
Furthermore, my next test is to add a PIX 515UR to the mix, and figure out how to connect IT to both switches.
I cannot find any information about how to bond or team interfaces on the PIX, can it do something like this?
