First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.
VeDSL : The Other Voice Choice
- — 25 July, 2000 14:28
Voice is king from a revenue perspective, which is the reason most data-centric providers look at options to offer a voice service. The voice over broadband market is still in the "let's test it and see if it works" stage. Many trials are going on using voice over DSL and cable modem technologies but there are no wide-scale deployments to date. VeDSL provides an option for DSL providers to enter the residential market quickly.
If you're thinking just what I need, more alternatives, hold on. This one might make life easier. Adding voice to a DSL circuit using traditional voice over DSL technology adds complexity to your network. It typically requires an integrated access device on the customer premises, ATM all the way to the IAD for voice transport, permanent virtual circuits (PVC) for voice transport and a gateway that reconstructs the voice packets to be received by the Class 5 switch via a GR-303 interface. VeDSL uniquely allows you to eliminate three of these components.
So how does it work? VeDSL transports voice within the physical layer while supporting plain old telephone service and standard DSL data access - there is no need to packetize the voice traffic into upper-layer protocols such as IP or ATM. Therefore, you avoid adding complex components to your network. VeDSL reserves a portion of the total DSL bandwidth for voice depending on the number of lines and allocates the remaining bandwidth for data applications. This bandwidth allocation is dynamic so when no voice lines are in use, the entire amount of bandwidth is available for data applications. Voice calls automatically take over their necessary bandwidth when activated. The bandwidth per voice line can be either 64K bit/sec or 32K bit/sec, depending on compression. Other voice line functionality such as caller ID, call waiting, etc., as well as dial-up access and fax transmissions are all supported.
VeDSL also lets you to offer voice without implementing a gateway, ATM to the IAD, and PVCs for voice transport. These are significant benefits for you. Gateways are rapidly progressing and quickly becoming carrier class. However, their existence in the network will probably require a change in the operation support system. Since the voice is transported at the physical layer, there is no need for the ATM to the IAD. This also eliminates the need for PVCs for the voice transport, resulting in cost savings and a less complex network. Echo cancellation is not as big an issue because VeDSL contributes less latency than voice over DSL technology.