09-29-2015 11:34 AM
I'm troubleshooting an issue where several routed networks, on the other end of a Brocade NetIron CER, dropped out for a few minutes. I initially thought it lost its IP routes but those were still present. I confirmed that it wasn't a broadcast storm or a failing switch. It really looked like an STP flapping issue, however STP was stable. Basically my outside interface (which faces an OSPF layer) is ethe 2/1, the 'other end' interface is ethe 2/2 and I have one other network that connects off ethe 1/4.
After further looking, it now seems like traffic destined for the networks behind interface ethe 2/2 might have been passed to interface ethe 1/4. I see bandwidth graphs that show traffic to interface ethe 1/4 really spiked during this event. With the routes in place though, I can't imagine why it would do that.
I then noticed that by default the Brocade NetIron CER puts all its interfaces in a default VLAN, VLAN 1. By having all the interfaces in VLAN 1 is that creating a broadcast domain that includes all interfaces? Is it possible that some traffic destined for a network behind ethe 2/2, couldn't find that destination, then was broadcasts out 1/4?
Thanks in advance for any and all input