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Frame Relay and ATM Access

Frame Relay and ATM are specialised types of access (data) service which have only recently become available in Australia,(some capital cities only) from the major suppliers. They provide higher data rate access, typically from a few Mbps up to 155Mbps for ATM.
 

Frame Relay "Committed Information Rates"

Access to a frame relay network is typically available at a "port speeds" of 2Mbps. The port speed is the rate of the point-to-point physical link between a user's premises and the frame relay service.
 
Internally, the frame relay network is engineered on the basis that not all nodes will continuously attempt to transmit at their full port speed all of the time. In fact, each port is only guaranteed reliable service at an agreed "Committed Information Rate" (CIR). This is typically much less than the actual port speed, even down to 0bps. It is possible for a frame relay user to transmit up to the port speed -- in other words, continuously. However, the network is engineered so that reliable frame delivery becomes less and less probable as the average offered data rate rises above the CIR: ultimately, the network is permitted to drop frames.
 

ATM Service

ATM service is commonly used as an "integrated" (data/voice/video) service connecting multiple sites of larger businesses. A "virtual circuit" (perhaps of specified "sustained information rate" (SIR)) is configured within the ATM network, terminating at the ISPs POP. Use of technologies such as this only make sense in terms of an overal "communications architecture" for an organisation.
 
Lecture 15: Internet Topology and Structure Copyright © 2004 P.Scott, La Trobe University Bendigo.

Useful links

Kim Davies' Australian ISP List has details of all (known) ISPs operating in Australia.
 
Telstra Bigpond Direct
 
NSFNET history
 
Ameritech's Chicago NAP
 
Google Links to Internet History pages
 
Another bit of NSFNET history
 
The aus.net.access newsgroup sometimes has interesting discussions about Internet access in Australia.
 

The tutorial for this lecture is Tutorial #15.
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