Field Guide · concept

A gateway is a network node that joins two networks, acting as the entry and exit point through which traffic leaves a local network for another — most commonly the wider internet.1

local network external host host host Gateway one entry / exit point Internet / another network egress all traffic between the two networks passes through the one boundary node
A gateway is the single node where one network meets another. Hosts on the local side send anything bound off-network to it, and it forwards traffic out the one egress point — often translating between the two networks along the way. It names a role at the boundary, not one specific box; on a home LAN the router fills it.

Overview

On a home or office network the default gateway is usually the router: the address a host sends packets to when their destination is not on the local LAN. More broadly, a gateway can translate between dissimilar networks or protocols — bridging an IoT radio network onto IP, for instance — doing more than a router that merely forwards IP packets. The term describes a role at a network boundary rather than one specific box.

Where it fits

A gateway marks the edge of a network, which is also where edge computing and protocol bridging often live. In a distributed GopherTrunk setup a small box can act as a gateway, gathering decoded data from several capture nodes on a private LAN and forwarding it out through one egress point to a remote server.

Sources

  1. Gateway (telecommunications) — Wikipedia, on the node that joins two networks. ↩

See also