Router on a stick

The router has physical connections to the broadcast domains where one or more VLANs require the need for routing between them.

They use a single Ethernet network interface port that is part of two or more Virtual LANs, enabling them to be joined.

If they need to communicate, then a router must be placed between the two VLANs to forward packets, just as if the two LANs were physically isolated.

The only difference is that the router in question may contain only a single Ethernet network interface controller (NIC) that is part of both VLANs.

One-armed routers are also used for administration purposes such as route collection, multi hop relay and looking glass servers.

Cases where this setup is used can be found in servers dedicated for prints, files or for segmenting different departments.

[3] Enterprise networks implement this method of separating servers to prevent all users from ‘having equal access privilege to resources’.

[citation needed] Networks via router on a stick are independent from their physical locations, therefore sensitive data can be handled without compromise and with ease.

[1] If the router fails, there is no backup and that may become the bottleneck in the network, effectively making all inter-VLAN communication impossible.

Moreover, since all VLANs must traverse one router, there is a great potential in insufficient bandwidth provided for all network connections.