Gateway (Gateway) is also known as inter-network connector, protocol converter. Gateway in the network layer above the realization of network interconnection, is the most complex network interconnection equipment, only for two high-level protocols are different network interconnection. Gateways can be used for both WAN interconnections and LAN interconnections.?
A gateway is a computer system or device that acts as a switching heavyweight. Used between different communication protocols, data formats or languages, or even two systems with completely different architectures, a gateway is a translator. Unlike a bridge that simply conveys information, a gateway repackages the information it receives to suit the needs of the destination system. Same layer - the application layer.
Extended Information
Three major functions
The first is that it supports the neighbor acquisition mechanism, which allows one router to request another router to agree to exchange reachable information. We can say that a router acquires an EGP peer router or an EGP neighbor.EGP peer routers are neighbors only in the sense of exchanging routing information, regardless of their geographic proximity.
Second, the router continuously tests whether its EGP neighbor can respond.
Third, EGP neighbors periodically transmit routing update messages to exchange network reachability information.
Like GGP, EGP uses a query process to keep a gateway aware of its neighboring gateways and continually exchanges routing and state information with its neighbors.EGP is a state-driven protocol, meaning that it relies on a state table reflecting the condition of the gateway and a set of operations that must be performed when a state table entry changes.
Baidu Encyclopedia - Gateway