The Advanced Telecom Computing Architecture (ATCA) is an open standard optimized for next-generation telecommunications equipment that allows telecom equipment manufacturers to develop modular and interoperable hardware and software on a common platform. By using standard hardware and software building blocks from a variety of vendors, carrier-grade solutions can be developed in a shorter time and at a
reduced cost.

ATCA defines a packet-switched high-speed backplane that supports various standards, including Ethernet, Fibre Channel, Infiniband, StarFabric, PCI-Express, Advanced Switching, and RapidIO. With the focus on packet networks and high-speed serial interconnects, no backplane interface has been defined to distribute traditional TDM voice traffic. The assumption was that TDM interface modules would convert between TDM signals and packet protocols. As a result, designers must create their own architecture to support TDM.

The challenge lies in the fact that TDM traffic requires switching at DS0 granularity with minimal latency. Since voice service will remain a significant source of carrier revenue, even after the migration to packet-based and wireless infrastructures, the importance of TDM traffic distribution cannot be overlooked. This article will discuss three options for efficiently transporting TDM data in ATCA systems over an Ethernet fabric: I-TDM, proprietary TDM backplane, and TDM-over-IP.