Denser Base Stations, DSLAMs, and Access Switches

PMC-Sierra's three new Inverse Multiplexers for ATM solutions may provide ten times the density of traditional T1/E1 ATM inverse multiplexer designs, enabling denser metropolitan networks.

by Wayne Kawamoto [February 26, 2001]

PMC-Sierra announced three Inverse Multiplexers for ATM products.

The PM7341 S/UNI-IMA-84 is designed to support an industry leading 84 T1 or 63 E1 links [definition] in a single device and is optimized for T1/E1 over fiber applications in Multiservice ATM switches, Metro-Optical Access switches, and Third Generation (3G) Wireless Base Station Controllers.

The PM7342 S/UNI-IMA-32 is designed to support up to 32 links and is optimized for high density T1, E1, or ADSL over copper applications in DSL Access Multiplexers (DSLAMs), Multiservice Access Multiplexers, and 3G Wireless Base Station Controllers.

For low link count applications such as Integrated Access Devices (IAD) and 3G Base Stations, the company's PM7340S/UNI-IMA-8 is supposed to support up to 8 T1, E1, or ADSL links.

According to the company, service providers offer broad availability for 1.5 Mbit/s T1services. But the explosive demand for high data rate applications such as videoconferencing and LAN interconnect is driving the need for access speeds beyond 1.5 Mbit/s. And the next standardized service rate beyond T1 is 45 Mbit/s T3, which is often 10 times the cost of T1, has limited availability, and provides more bandwidth than many users require.

IMA technology is designed to bridge the bandwidth gap between T1 and T3 by combining multiple low cost T1 lines into a single higher speed service at multiples of 1.5, 3, 4.5, 6 Mbit/s or higher. In addition to IMA over T1, the S/UNI-IMA family should also support multiplexing of E1 and ADSL links.

"PMC's S/UNI-IMA products can be used in applications that require greater than T1/E1 bandwidth but do not have access to a DS3/E3 line service," says Tom Sun, director of strategic marketing for PMC-Sierra's Access Products Division. "With IMA technology, a service provider can adapt easily to its customer's changing bandwidth requirements by either increasing or decreasing the number of T1/E1/xDSL links in an IMA group without equipment change."

Pricing and availability
The PM7341 S/UNI-IMA-84 and PM7342 S/UNI-IMA-32 devices are packaged in a 27x27mm2 416-pin PBGA and are priced at $584 and $335 respectively in 1KU quantities through distribution.

The PM7340 S/UNI-IMA-8 is in a 23x23 mm2 324-pin PBGA package and is priced at $125 in 1KU quantities through distribution.

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