Digital Cross-Connects

Posted: 08/1999

Digital Cross-Connects
Gone But Not Forgotten
By Charlotte Wolter

The digital cross-connect (DCS), long a staple of low-bandwidth voice switching, is not about to be swept away, even with the likes of TransMedia Communications Inc., San Jose, Calif.; Castle Networks Inc., Westford, Mass. (acquired by Siemens AG subsidiary Unisphere Solutions Inc., Burlington, Mass.), Convergent Communications Inc., Englewood, Colo.; and Sonus Networks, Westford, Mass., incorporating cross-connect functions into their next-generation "softswitching" platforms.

Alcatel Network Systems, Richardson, Texas, has announced a new cross-connect, the 1630 GSX Global Synchronous Cross-Connect system, which it is calling a multiservice delivery platform. The product is aimed at carrier central offices (COs) now using manual cross-connects or Alcatel's own less-integrated products, and allows them to upgrade to an integrated narrowband/wideband unit without traffic interruption.

The network interfaces on the new product range from DS-1 and E1 to OC-3 and STM-1 with plans to migrate to OC-48. The product includes a nod to the growing importance of data with frame relay and asynchronous transfer mode (ATM) capabilities. The current matrix supports 8,000 DS-1 equivalents, with any mix of narrowband and wideband provisioning, and is planned to expand to 32,000 DS-1 equivalents.

Kent Novak, senior director of product management and marketing for narrowband systems, Alcatel Network Systems, says vendors are still serving a market where "more than 90 percent of all data circuits around the world are less than a DS-1, or less than 128kbps (kilobits per second). In voice services 98 percent of all traffic is narrowband."

However, the product strategy is to expand the functions beyond narrowband grooming. "We have a narrowband product," Novak says, "then we will expand to small wideband, then to termination of wideband equipment, then to data applications." Future plans call for direct interfaces to OC-3 and OC-12, enabling carriers to eliminate an add/drop multiplexer.

The programmable switch startups seeking to compete in the CO Class 5 switch space have almost all incorporated cross-connect functioning in some way, says telecommunications analyst Deborah Mielke, Treillage Network Strategies Inc., McKinney, Texas. "All these companies are trying to be the bridge between the old and the new. Castle set out to take over some of the DCS functions. Sonus not as much. Salix Technologies [Inc., Gaithersburg, Md.] started out not to and ended up doing it because of what customers asked for."

Nevertheless, that does not do away with the cross-connect market, Mielke says. "Carriers still have to groom transmissions, and there is still lot of low-speed bandwidth. There is still a lot of 56kbps frame relay, and it's not going away," she says. "It will change as carriers' customers start looking to do voice and data over one pipe, but that is still a couple of years away."

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