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Technology Stocks : LAST MILE TECHNOLOGIES - Let's Discuss Them Here -- Ignore unavailable to you. Want to Upgrade?

To: Frank A. Coluccio who wrote (11560)	6/25/2001 10:59:47 AM
From: MikeM54321	Respond to of 12823

Frank- There has been a lot of confusion about cable voice. I think you are correct. Ray was assuming(as in his video conferencing example) it would be VoIP over the public Internet. But cable IP voice would be only taken to the headend where it would be passed onto the PSTN as you state. -MikeM(From Florida)

To: Frank A. Coluccio who wrote (11560)	6/25/2001 12:46:16 PM
From: Raymond Duray	Read Replies (1) \| Respond to of 12823

Hi Frank, Thanks for the explanation of the MSO VoIP network solution. Seems that I wasn't clear on the concept. Since the MSOs are in need of a softswitch vendor, or a link to the PSTN, with a concommitant access charge, that the economics of this solution don't make the least bit of sense to me. Particularly in light of the fact that CableLabs seems to have given up on the concept of competing on "life-line" service. Anyone done any "back of the envelope" calculations on what the MSOs could expect to sell this VoIP service for? The only way I see them selling it is as a LD meter killer, i.e. offering unmetered long distance telephony for a fixed monthly fee. Comments welcomed! -Ray

To: Frank A. Coluccio who wrote (11560)	6/25/2001 3:33:51 PM
From: DenverTechie	Read Replies (1) \| Respond to of 12823

Frank, I wanted you to know that you have captured the gist of the matter regarding cable MSO IP Telephony (we don't even call it VoIP anymore BTW). The IP Telephony monikor is meant to signify that cable "VoIP" is carrier-grade. That is, that it has equivalent quality with PSTN voice traffic. That is not to say that CableLabs (which is as much a political institution as much as a technical one) has "given up" on the idea of carrier grade primary line service in its PacketCable initiative. To satisfy the requirements of all its constituents though, it has to incorporate many compromises, which starts to move us away from primary line service. Suffice it to say, the individual MSOs have not abandoned the IP Telephony carrier grade primary line model at all. Far from it. As to how IP Telephony QoS is maintained throughout the entire network connection, you have nailed it down well. First, IP Telephony was never intended to operate over the public Internet. It has 2 distinct flavors, as you point out. The "easier" IP implementation is actually only IP Telephony in the access network. Once at the headend, the voice signal is converted to TDM by use of an IP to TDM Gateway device, usually installed at the headend. Then the transport network brings the voice traffic to the existing Class 5 switch (either owned by the MSO or a partner) for connection to the traditional PSTN. The call is terminated at the far end by either the MSO's IP network or the PSTN. Because service providers like AT&T can provide both the local access, the transport, switching and LD network, the economics of this type of solution are well grounded. The other type of IP Telephony is what is dubbed "end-to-end IP Telephony". In this case, you install a soft switch and various other server mechanisms to take the place of the monolithic Class 5 PSTN switch. The functions are not so much physical as logical (that is, it does not matter where in the network the box resides as long as it has logical connectivity to the rest of the network). There are several ways we control QoS and obvious impairments such as latency and jitter. The main component is what we call the "managed IP backbone". This type of private IP network has network management that determines the route the voice call will take through the network, determine how many router hops it will take and automatically reroute the call if it will take too many hops and thereby introduce too much delay. It thereby restricts the number of routers the call goes through on a managed basis, such as specifying the call cannot traverse more than 7 backbone routers (as an example only). Of course, on the far end, the terminating point may not be on an IP Telephony enable access network, so an IP to TDM Trunk Gateway is needed to access the local PSTN switch on the far end. There are currently trials underway and planned deployments of both types of IP Telephony which are set to be carrier grade primary line service right now at several major MSOs. Hope that clarifies things a bit more, let me know if you have any other questions on this.