Network gateway is a device that allows connection between two networks using different types of protocols. Gateways convert one type of protocol to other type allowing communication between two different protocols. For example a network with TCP / IP can be connected to X.25 using a gateway. A gateway works on session and above layers of OSI model. Important specifications regarding gateway include network type,
form factor, port, performance,
memory, processor, and extra features.
Gateway Protocol Specifications
The most important thing while selecting a gateway is the type of the network it can work with. The network type is defined by the protocol, network using. Gateways support almost all the protocols. These include IPX, TCP / IP,
Ethernet, Token Ring, DSL (digital subscriber line, xDSL), ATM (Asynchronous Transfer Mode), ISDN, SONET, and ARCNET. One most common example of gateway application is IP telephony. In IP telephony network gateways are used to convert between the voice and Internet protocol. These gateways allow the PC to send voice calls not only over the Internet but also other packet networks.
Gateway Performance Specifications
Performance of a gateway is based on the data rate, number of users, and I / O ports.
Data Rate
Data rate is major concern since different networks use different data rates. Data rate means that the maximum speed at which a gate way transfers the data. Gateways allowing different data rates are also available.
I / O ports
The second thing that affects the performance is number of I / O ports. The number of I/O ports allows associating other network equipment with the gateway. A gateway contains all or any of these ports: BNC, AUI, FireWire, Universal serial Bus (
USB), RJ-45 ISDN (BR S/T, BRI U), ST, MIC, GBIC, and
serial ports.
Users
Numbers of users define that how many networks can be controlled by the gateway.
Gateway Form Factor
Gateway is usually available in three form factors. These include
integrated circuits,
printed circuit boards, and modules. As an integrated circuit a gateway can be integrated in network
devices. PCBs can be inserted into the
network equipment or
motherboard slots. As a module a gateway is a standalone device and can be connected to the network externally.
Gateway Extra Features
The optional features associated with gateways can be interfaces such as LCDs or LEDs, integrated firewalls,
mounting style, stackable, and VPN.
LCDs or LEDs are used as indicators to display information such as data is transmitted or error indication. Some gateways contain an integrated firewall that allows data integrity and security. In mounting some gateways come in rack mount styles. One important feature of gateways is VPN connection. Some gateways support this connection that occurs over a shared network but offers the benefits of a dedicated link.
