Jon Crowcroft writes:
weel, for toll quality speech, we can get down to around 16kbps per user, i.e. 4 per 64kbps, i.e. nearly 100 per 2Mbps, or 30,000 per 622Mbps...
now assume that out of the worlds 600M phones, 10% are active
This might be realistic but is actually on the higher side.
and assume that most calls (say 90%) are local then we need to tolerate a total of 6M calls....(this is WAY higher than they actually do...)
Exactly. The average active international call count for 3 million finnish telephones is less than a thousand. That would make the international call percentage 0.033% of active call minutes which sounds realistic.
assume that we build a path disjoint backbone, so continental locality is also kept reasoanbly well (and timezones help anyhow) - we need to support 600,000 calls on an Internet trunk...
And with the above more realistic figure, this number comes down to 20000. Which in order sounds still high knowing the infrastructure in existence to carry the calls.
so we are out by 20 times right now.....
Take a short look how many bits per second is actually in use between the continents and then figure out where the phone calls must fit :-)
ok, so we put in a 16 fold replicated backbone global grid...then we're there
but there are 800k web browsers in the UK after our interntational links anyhow, so we need to upgrade anyhow...
so they'd all suddenly get instantaeous reponse...
oh, the cost?
tricky one:-)
When we get more privately funded intercontinental cables like FLAG, the availability of bandwidth for a reasonable price will be here. Until then, we've just wait for the internet-aware cable investors to pop up. Note that it takes half a decade from a plan to a cable. Pete