application level gateway is also known as

Introduction of H.323: Recommendation H.323 (ITU, 2003a) is a set of protocols for voice, video and data conferencing over packet-based networks. We should take some other measures to resolve this problem. However, there are many problems to achieve NAT for VoiP, because the IP address and port number used during call setup is inside their data payloads, NAT works only at the IP and TCPIUDP levels.

As a basic application of router, NAT should support those services. Multimedia real-time services like audio, video communications, especially VoiP, have been made rapid progress in recent years (Boucouvalas, 2002). NAT can also save network administration costs by reducing the number of public IP addresses that must be purchased or leased from a service provider. Address mapping and port translation effectively conceal the size and topology of the private network, providing a basic level of security. A device running NAT can connect an entire department or small office to the Internet using only a single global IP address. Network Address Translation (NAT) (Srisuresh and Egevang, 2001 Senie, 2002) is widely used in routers, firewalls, DSL and cable modems. PDF Abstract XML References Citation How to cite this article The experiments demonstrate it very efficient and feasible. The concept of sub-flow classifier for H.323 packets is also proposed to shorten the call set-up time. An ALG may interact with NAT to set up state, use NAT state information, modify application specific payload and perform whatever else is necessary to get the application running across disparate address realms. In this paper, the author presents a new method, Application Level Gateways (ALGs), to allow an application on a host in one address realm to connect to its counterpart running on a host in different realm transparently. But real-time applications such as voice over IP use IP addresses and port numbers inside their data payloads.

NAT works at the IP and TCP/UDP levels by translating the address and port numbers in the IP header and TCP/UDP header, respectively.

Network Address Translation (NAT) has become a powerful function of routers, which effectively conceals the size and topology of the private network from the outside.

Application level gateway is also known as