An Ethernet switch for use in an Ethernet network comprises a set of ingress ports for receiving data frames and a set of egress ports. A memory is associated with each ingress port and stores forwarding information indicating one or more of the egress ports to which data frames received by that ingress port should be forwarded. A control or management interface receives information about a network connection established, or to be established, through the switch. A switch controller causes forwarding information to be stored in a memory associated with a first ingress port which the network connection will use, on the basis of the received information about a network connection. Forwarding information is not stored in a memory associated with a second of the set of ingress ports which the network connection will not use. Preferably, the switch controller causes forwarding information to be stored only in a memory associated with the first ingress port which the network connection will use and not to be stored in a memory associated with any of the other ingress ports.