TDM over Ethernet

 
If end user applications only required Ethernet access services, a Metro Ethernet connection along with an intelligent Ethernet NTU device or an Ethernet rate and media converter might be adequate to satisfy their needs. However, the installed base of TDM equipment and services is very large and continues to grow. In fact, the Metro Ethernet Forum (MEF) has defined TDM support as one of the five basic attributes that define carrier-class Ethernet. E1/T1 circuits are also extensively used in enterprise voice networks, requiring efficient solutions to deliver E1 over Ethernet transport.
 
Traditional PBXs use E1/T1/PRI circuits as the primary connections to service providers as well as for inter-facility voice trunking. Although many organizations are moving to replace these systems with IP PBXs, this transition will take years or decades. In fact, a large percentage of organizations have no current plans to move to VoIP – they are perfectly happy with their existing functional and reliable phone systems.

Once organizations begin using high bandwidth, low cost Ethernet connections for LAN traffic, they will naturally want to converge most, if not all, of their other types of telecommunications services—like their TDM PBX trunks onto Ethernet. But as just discussed, these other “non-Ethernet” services are typically TDM circuits that are not compatible with packet transport. 
 
RAD’s EtherAccess® product family employs an industry standard pseudo-wire or circuit emulation technology for transparently transporting E1 over Ethernet as well as T1 or E3/T3 TDM circuits over Ethernet, IP or MPLS networks. The EtherAccess product devices, based on RAD’s standardized TDM pseudowire technology, feature a variety of techniques for overcoming the challenges of packet delay variation (aka jitter), packet delay and packet loss as well as the absence of an inherent timing mechanism, which create a hostile environment when synchronously transmitting TDM over Ethernet.