
		AT&T Laboratories Cambridge

ATM switches

Our ATM switches have been designed with simplicity in mind. The approach taken is very soft and modular which gives a flexible approach to cell switching with a minimum of special hardware. At the heart of the switch is an ARM 610 processor. In the local area, links consist of bi-directional coax cables driven at 100Mbit/second by TAXI chips. Converter boxes allow fibre to be used over longer distances. ATM Forum protocols are used up to the Network Link Layer, and we have adopted the AAL5 Adaptation Layer. Proprietary signalling code (MSNL) is currently used for virtual circuit set-up. The network consists of about of about 40 4-port switches and 20 8-port switches. There are about 200 Smart ATM Modules connected to the network. A topology determination service helps us keep track of things.

The 4-port switch has an aggregate throughput of around 200K cells/second.

The 8-port switch has an aggregate throughput of around 1M cells/second.