What is "one-armed router"

n. A special variety of router used to route packets in a VLAN environment. Because a one-armed router uses the same physical link to send and receive traffic to and from different VLANs, this is also known as a ''router on a stick''.

In computing, a "one-armed router", also known as a "router on a stick", is a router that has a single physical or logical connection to a network. A one-armed router is often used to forward traffic between locally attached hosts on separate logical routing domains or to facilitate routing table administration, distribution and relay.