Presence and IntComm WG

[(Dennis Baron)]

> Does anyone have busy-hour call volume figures from a campus voice
> switch they could share?  With a few datapoints, I'd do this
> back-of-the-envelope analysis.

I haven't done this for years - but I was going to guess 3CCS/line busy hour 
usage.  Google got me one of Hennings' pages...

Source: http://www.cs.columbia.edu/~hgs/internet/telecom.html

> PBX and Central Office Dimensioning
> 
> Engineering and Operations in the Bell System (p. 125)
> type of office        CCS/hr  Intraoffice (%)
> Urban         3.1     31
> Suburban      2.7     54
> Rural         2.1     66
> Briley, Telephone Switching, p. 141: average origination: 3 calls/hour, 3 
> minutes/call (= 5.4 CCS/hour/subscriber)
> 
> Deutsche Telekom: 50% of local calls are shorter than 90 seconds
> 
> CCS: hundred call seconds/hour (fully used: 36 CCS) BHCC: busy hour call 
> capacity
> 
> roughly 10 calls (internal/external) per station per hour
> 
> GMD: 5 external lines per 100 stations; for 3 minute calls, 20 
> calls/hour/line; thus, 1 external call/hour/station. 

My back-of-the-envelope says that all MIT's external voice traffic will fit on
a singe DS3 - so if it all went out over I2 it would only take about  50mbps 
of
bandwidth.  That's not what's going to kill us - it's "Hi Ben, I'm going to
watch a movie - want to watch it with me?  I'll send you a stream and we can
make fun of the bad acting together."

                                Dennis


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