A table which contains details about the topology of a network. It has details of every computer in the network together with the connections between them. More sophisticated tables also contain dynamic data which describes the state of the network in terms of the amount of traffic passing though the transmission media joining each computer. A routing table is used to determine an optimal path from a source computer to a destination computer on the network. See also routing. It is also a table associated with a firewall router which contains the IP address and port number of the computer sending a packet and the computer receiving a packet and specifies, based on this data, whether or not the packet is to be rejected by the router.