Just a strange problem I've found on the network. Last weeks, after replacing a RB450G for a RB1200 as the core router for the network, users are complaining that network speed was much lower than usual. Doing some testing, we saw ping times to the router (within local subnet) jumping everywhere between 1 ms and 20 ms. The setup consist of a gigabit switch connected to port ether9 of the RB1200. Traffic passing the interface is between 8 and 12 mbit continously in both directions.
These are the things we've seen...
- When connecting a test laptop (192.168.3.x) and pinging the router (192.168.3.1) on local subnet through the switch we get everything between 1 and 20 ms RTT.
- After disconnecting all other devices on the subnet, no traffic passing to the router, ping times to the router are a rock solid <1 ms.
- When connecting the devices back to the switch and traffic is again flowing through the router, ping times are back between 1 and 20 ms.
Ether9 is in a bridge called LAN. This morning, I've added Ether8 to this bridge and swapped the connection from Ether9 to it. From that moment, ping times, even with all normal traffic flowing the router, are good, all <1 ms or 1ms. Next test was for Ether10 (WAN connection), swapping it to Ether7 and the problem went away too.
Are ports Ether9 and 10 different from Ether 6, 7 or 8? I know ports 1-5 are in a separate switch to the CPU, but how about the rest? Does anybody has seen this kind of behaviour?