Stephen M. Bellovin wrote: >If you're doing >uncompressed voice (compression makes this effect worse), a 1500 byte >packet holds 214 ms of voice at the (U.S.) standard rate of 56K bps. >That's already beyond the delay budget, just for that one hop,
On the other hand, that's assuming POTS-grade audio quality. Some people could have use for higher-quality audio. For example, radio stations prefer to use high-quality audio when doing interviews with people in remote locations. Musicians could use CD-quality audioconferencing to practice together remotely (for example, if Big Stars from different continents are preparing for a live show together); at 176K bytes/second, a 1500-byte MTU is less than a single millisecond, meaning you'd have to route more than 1000 packets per second. (And that's just for stereo; And then there's video; given FTTH, it could be practical for a TV news program to do an IP-based videoconference when it needs to interview somebody remotely. Since by then we'd be talking about HDTV, they'd need a huge bit rate; individual frames could easily turn out to overflow the 1500-byte MTU. I know this is stuff that's been talked about for a long time, and has remained impractical (I used to work in videoconferencing); but the biggest part that makes it impractical has been bandwidth. FTTH would increase that bandwidth, so it does seem like something for a body working on FTTH to consider. /========================================================\ |John Stracke |Principal Engineer | |[EMAIL PROTECTED] |Incentive Systems, Inc.| |http://www.incentivesystems.com |My opinions are my own.| |========================================================| |Cogito ergo Spud. (I think, therefore I yam.) | \========================================================/
