I wonder if PAGP/LACP constantly exchanging PDUs between peers or only during negotiation phase? I would like to aggregate 8 ports between c4500 chassis and 2960 switches, but optical-udp media converters are in use for the links. If I just make fixed configuration putting ports in etherchanell group then I have a problem with end to end link failure detection. So, maybe if I use dynamic port channel configuration with PAgP or LACP maybe I'll get port aggregation and end to end failure detection. Right? I ask because at this moment I don't have equipment to conduct some lab tests about this.