[VOIPSEC] IPv6 and the demise (or not) ofNAT(wasRe: Interactive Connectivity Establishment (ICE))

[Randell Jesup]

Volker Tanger <vtlists at wyae.de> writes:
>Let's do some rough calculation: taking for example Voice, GSM codec
>(13kbit/s), SIP, RTP+RTCP, thus ~60kbit/s total bidirectional traffic
>for each conversation (including overheads). Thus a 1Gbit/s (eth
>interface) system will probably max out at around 10.000 simultaneous
>calls ethernet-wise. Pretty much suitable for the very most companies
>and campuses.
>
>For current video telefphony (Cisco Video Link) data only is 384kbit/s,
>thus with overhead probably a bit above 2 Mbit/s, thus maxing out the
>Gbit-link around 300 simultaneous calls. Which is a bit limiting,
>especially for bigger companies. 

        Overhead is mostly fixed per-packet overheads, not percentage-wise
anywhere close to audio overhead.  You do have roughly twice as many
packets, so total overhead is higher.  With 384K video and the same
audio as above, the total would be well under 500Kbps, not 2Mbps.  So
more like 1200 calls.

-- 
Randell Jesup, Worldgate (developers of the Ojo videophone), ex-Amiga OS team
rjesup at wgate.com