node... ...a device on a network
central node... ...a node in a network that all other nodes connect to
traffic... ...the data sent between nodes on a network as they communicate
single points of failure... ...areas where a failure will affect other kit, curable with redundancy
redundancy... ...the duplication of devices to allow for failure
failover... ...a redundant device picking up the tasks of a failed redundant device
router... ...a network node that links networks together, allowing traffic to flow between
routing... ...what routers do
firewall... ...a router (usually) that filters the traffic flowing though it