Broadband data communications

Broadband standards are still being defined today, with ATM receiving the bulk of attention.SS7 will not carry the actual user data, but will provide the services neccesary to connect the end to end telephone network company facilities required for data transfer between two end points.The specific requirements of SS7 are still being defined.The trial network using ATM do not require SS7, because the trials being performed with broadband ISDN and ATM are currently permanent virtual circuits (PVC) and are not switched. However as the new services are not deployed for public access, SS7 will provide the signaling for ATM

ATM is a transport protocol which relies on upper layer protocols for functions above adn beyond the layer three.The ATM technology was created for support broadband ISDB but has found favor with a number of other nnetworking protocols as well..Frame realy with speed up to 155 Mbps will most likely serve as a good solution for those requiring a PVC service.These work much like a dedicated special circuit adn are not typically swithced.However there are plans to provide switched frame relay, making it a viable service for switched data network.

Narrowband ISDN (1.554 Mbps) is being suggested by many services providers as a cheaper acces to broadband services,while broadband ISDN (155 Mbps) is being targeted at a mega network who need much more bandwidth

Broadband ISDN (BISDN) will provide fast data transmission for service such as video dialtone.With the bandwidth of BISDN video and audio can be transmittedsimulatneosly on the same facility.This willprove to be an imortant feature for the information highway.

A point that often gets lost among all the marketing hype over ATM is the purpose of this technology.Talk of a new telephone network is nothing new.Telephone company officials have been palnning for many years to upgrade their old analog networks to support the services and applicaitions under much demand.Subscribers are not longer complacent with slow data transmission and expensive special circuit for sending data and other information through the network

ATM was developed to support the broadband ISDN interface being defined for customer premise.Many vendor have placed ATM switch inthe hands of customers (philosopically), thinking this will meet the need of every businness and become a necessity in office buolding everywhere.Some have even been so bold as to claim that ATM will replace the local area network.

In reality ATM will only be found at customer premises where nothing else will deliver to the bandwidth required for video service.ATM would be much too expensive for the average business to deploy in place of a LAN, and certainly consitutes overkill for most daily business activities.But for university needing the 600 Mbps of badwidth and the hospital using the telephone network to send high resolution medical image, ATM and broadband ISDN are likely to be an integral part of their networks.

Narrowband ISDN will serve as the customer interface for the majority of subscribers, while ATM and broadband ISDN will become the transport mechanism within the telephone network to the destination.

ATM require a transmission facility capable of carrying the bandwidth (600 Mbps and higher).Syncronous optical network (SONET) is being deployed as the physical medium for ATM