Vance Shipley <vances@xenitec.on.ca> (09/28/90)
This thread has taken us into a discussion of Voice Packetization. One of my favourite subjects in telecom! As has been noted, virtually ALL voice traffic is carried over circuit switched channels with fixed, dedicated, bandwidths. No extra traffic capacity is realized when breaks in the conversations take place. By packetizing the voice traffic, and using common circuits to route it, utilization would be optimized. I'm sure the Digest will hear many reasons why this is not currently done, why it shouldn't be done on public networks etc., but I wish to put forward an ideal application for transmission of voice information by packet technology. VOICE MAIL NETWORKING! Many voice mail systems on the market have networking capabilities; Meridian Mail, Octel and others. The way they "network" is by allowing users to compose messages locally and then the system batches many messages for later transmission. One call is placed to the remote system and the messages are played back along with the necessary DTMF commands. Now remember that these same voice messages were digitized and compressed for storage on the system when they were recorded. Now they are uncompressed and turned back into analog for transmission and put back on disk at the receiving end! Now this may be neccesary in a multi-vendor public network but what about the corporate ISDN network? The way it should work is this; a user calls another user at another location and he is forwarded to voice mail. He hears the outgoing message of the other user but is connected to the local voice mail system, for composition of a message, automatically. The expensive, circuit switched, long distance connection is dropped. Once the message is digitized, compressed and stored it is ready for transmission. A connection is established to the far end voice mail system again, but this time it is a packet connection. In the ideal situation it is over the D-channel of the TIE lines to this location using what would otherwise be unused bandwith (in ISDN PRA the D-channel is allocated 64K which is far more than it needs for most applications). This scheme takes advantage of the compression techniques inherent in voice mail systems, the lack of a real time delivery need and the unused bandwith of existing facilities. Should be a winner don't you think? Any comments? Vance Shipley SwitchView - The Linton Technology Group Waterloo, Ontario (519)746-4460 vances@ltg.on.ca.UUCP