TDMoIP vs. VoIP - Matching Technology to Requirements

Why migrate to IP? – Connecting traditional voice, video and data over IP/Ethernet/MPLS networks has become an attractive alternative to running parallel voice and data networks. It saves money on call and leased-line service charges, while consolidating management, cutting maintenance costs, and increasing user productivity. This is achieved by converging two important traffic types onto one infrastructure and takes advantage of the simplicity and efficiency of IP routing and Ethernet switching.

Obstacles – Since Voice over IP (VoIP) was first introduced in the mid-90s, many industry analysts, service providers and vendors expected it would be the future technology of choice for both carrier and enterprise telephony services. Nevertheless, multiple standards and technological immaturity, compounded with the recent economic downturn, have considerably slowed VoIP adoption rate.

Benefits – The merits of VoIP based services, compared with traditional TDM and Leased-Line based solutions lie in the compression and packetization of the voice traffic (enabling cost-effective transmission), as well as in the switched architecture that further optimizes switch resources and allows for effective service oversubscription. Voice switching is particularly important in environments where the existing PBX/switch facilities are inadequate. It is of lesser importance in typical trunking applications with denser traffic, where the added value of switching can be outweighed by the simplicity of a non-switched solution.

Price – The benefits of VoIP deployment come at a price. This is in the form of forklift upgrades of core and edge infrastructures offered by the newer VoIP insurgents or adaptation of existing equipment by incumbent legacy switch vendors who are promoting a less radical migration path to VoIP.

Future – While VoIP is constantly growing, carrier conservatism and a tremendous installed base of feature-rich legacy PBXs in the enterprise environment will cap VoIP growth rate in the short term until either economics change, technology issues are resolved and/or existing equipment is depreciated. This creates an opportunity for a more evolutionary solution that will benefit from the merits of both worlds: the quality of service and rich feature set of yesterday’s technology, with the cost effectiveness of tomorrow’s backbones.

Pseudowire Emulation using TDMoIP (Time Division Multiplexing over the Internet Protocol) is a transport technology developed by RAD Data Communications that extends T1, E1, T3 or E3 voice or data circuits across packet-switched networks simply, transparently and economically.

TDMoIP vs. VoIP – In this paper we compare TDMoIP Pseudowires with VoIP. We see how TDMoIP psuedowire multiplexing technology enables better bandwidth utilization (up to 60% less generated traffic compared with VoIP) and how its transparency to standard and proprietary signaling protocols eliminates the need for forklift upgrades and PBX fine-tuning. We describe how TDMoIP pseudowire works and show 12 sample applications, such as trunking, cellular backhaul and enterprise PBX connectivity over IP.

RAD manufactures both VoIP and TDMoIP pseudowire products.