A gateway is a network element that acts as an entrance point to another network. An access gateway is a gateway between the telephony network and other networks, such as the Internet. Access mediation supports the arbitration of call control and signaling between individual networks, resources, users, and services. Access mediation is the next evolutionary step for the advanced intelligent network (AIN). With the growing importance of the Internet, access gateways are a critical component of access mediation.
This tutorial presents several application scenarios that utilize an access gateway point between the traditional telephone network and the Internet.First, the tutorial will review general background information on access mediation. As part of this overview, specific information on the important components of access gateways will be addressed. Access gateway-application scenarios will also be discussed. Finally, the tutorial will present several elements of network design that are crucial for a network to support an access gateway.Access mediation supports the arbitration of call control and signaling.
The key mediation functions to be managed and controlled include privacy, security, message routing, message screening, message parameter screening, bridging and protocol conversion, performance monitoring and protection, error handling, and billing. The goal of access mediation is to enable the interconnection of individual networks.As an important application area of access mediation, access gateways allow networks based on different signaling protocols to be interconnected. For example, telephone company mergers have created the need to interconnect networks based on different signaling standards. Wireless networks based on GSM must now interconnect with networks based on IS-41. The access gateway provides the protocol conversion needed to interconnect these networks.
The very first device that had fundamentally the same functionality as a router does today.
The idea for a router(called"gateways” at the time) initially came about through an international group of computer networking.
The first multiprotocol routers were independently created by staff researchers at MIT and Stanford in 1981
• A multi-homed device can act as a gateway that enables communication between the wired ad-hoc network and the infrastructured network as presented.
• IPsec provides Communication integrity and confidentiality between the gateway and the gateway client.
• In short, the gateway is just a router.
Access Network: The gateway can communicate with the infrastructured network through the access network.
Infrastructured Network: The infrastructured network is the Internet or an intranet. It is also possible that the infrastructured network and the access network are the same entity
CHOOSING THE GATEWAY SOLUTION
A 3G device can use its local 3G radio link to provide the gateway service to itself. When configured correctly, it can directly access both the ad-hoc network and the infrastructured network.
For example, if the devices are used in a foreign country, one of the devices might have a local USIM or SIM that enables Internet access at a moderate charge. Still, this solution is not very useful under normal circumstances.
specification describes a gateway for ad-hoc networks
The business model of the gateway is shown in Figure
The gateway provides the DNS service and IP based access to the infrastructured network
Discover: The user discovers the available gateways.
Connect: The user connects to the gateway. This enables the DNS service and IP based access to the infrastructured network.
Disconnect: The user disconnects from the gateway.
Use DNS Service: The DNS service allows applications to resolve host names into IP addresses
GATEWAY PROVIDER FUNCTIONS
Start: The gateway provider starts the gateway. This allows other devices to discover the gateway and connect to it.
Stop: The gateway provider stops the gateway. This disconnects all connected devices and prevents devices from discovering the gateway
Functional requirements and nonfunctional
Functional requirements are related to required functionalities.
Non-Functional requirements are related to the properties of the functionalities