I have Cisco ME 3400, and connected three host machines. It has been seen that these users are not getting ping reply to each other. Nothig n has been configured on the ME3400.
What could be the problem ?
The ME3400 is a metro ethernet switch and does not act as a standard switch stright out of the box. You have 3 interface types UNI/ENI/NNI. NNI acts the same as a Promiscuous mode when using private VLANS and UNI acts as isolated, ( ENI is the same as UNI but allows BPDU's and some other protocols to pass ). If all you want is the 3 hosts to talk, then just make all the interfaces you want to communicate NNI using the port-type nni interface level command. There are other ways of making this work by using private VLAN setup as NNI should normally only be used as an uplink for all UNI/ENI interefaces, but I would seriously consider re-evaluating the use the ME3400 in your setup.