I'm having trouble tracking down the source of some intermittent packet loss on one part of my network over the past few days (it's been solid for the last several months).

3 RB532A running ROS 5.5, 2 Cisco switches, with wireless (5ghz/nv2) between R1 and R2 (station-bridge mode).

C1 > R1 > R2 > C2 > R3

Reviewing logs from all devices, there are no interface resets, the wireless is going strong (-45 with no drops), yet R2 and R3 will randomly timeout and raise alerts (both nagios and The Dude).

No traffic passing from C1 to R2, yet from R1 to R2, it works fine. I check the ARP and routing tables, and everything is in it's place. A few minutes later (without intervention), everything starts working again.

This has me scratching my head... any suggestions on where to look for a cause?

Try to fix ethernet port speed on C1 and R1 (100M, full duplex, no autonegotiation on both sides).