GATEWAYS A Gateway is a combination of hardware and software,
network point that acts as an entrance to another network. A
computer network is a collection of interconnected computing
devices that can exchange data and share resources. A network's
protocol specifies a common set of rules and/or signals, such as
Ethernet or Token Ring, which the networked devices use to
communicate with each other. Each network must have associated with
it a well defined language or protocol to enable the respective
computers on the network to be able to communicate. Different
networks, however, often use different protocols such that
computers on one network may not be able to communicate with
computers on another network without the assistance of a device or
process to translate between the two protocols. A gateway is such a
machine that performs the translation between two disparate
protocols. Gateways perform code and protocol conversion to
facilitate traffic between data highways of differing network
architecture. At present, the gateway location protocol (GLP) as a
method for linking the plurality of address translating servers has
been started to be examined.The GLP is a protocol used to reduce a
load on a server and exchanges address information so that a
plurality of servers holds the same information. Gateways make
communication possible between different architectures and
environments. They repackage and convert data going from one
environment to another so that each environment can understand the
other's environment data. A gateway repackages information to match
the requirements of the destination system. Gateways can change the
format of a message so that it will conform to the application
program at the receiving end of the transfer. A gateway links two
systems that do not use the same:
Communication protocols
Data formatting structures
Languages
Architecture
For example, electronic mail gateways, such as X.400 gateway,
receive messages in one format, and then translate it, and forward
in X.400 format used by the receiver, and vice versa.
To process the data, the gateway: Decapsulates incoming data
through the networks complete protocol stack. Encapsulates the
outgoing data in the complete protocol stack of the other network
to allow transmission.
On the Internet, a node or stopping point can be either a
gateway node or a host (end-point) node. Both the computers of
Internet users and the computers that serve pages to users are host
nodes. The computers that control traffic within company's network
or at your local Internet service provider (ISP) are gateway nodes.
In the network for an enterprise, a computer server acting as a
gateway node is often also acting as a proxy server and a firewall
server. A gateway is often associated with both a router, which
knows where to direct a given packet of data that arrives at the
gateway and switch which furnishes the actual path in and out of
the gateway for a given packet. A gateway may consist of devices
such as protocol translators, rate converters, matching devices,
fault isolators, or signal translators as necessary to provide
system interoperability.
