[mythtv-users] Way OT: High-speed Data Service Delivery

[Richard Morton]

The key point of advantage between copper and fibre is protection from cross
talk and other interference. Fibre is pretty immune. On the other hand fibre
has a shorter lifespan is more expensive and is more fragile.

Virgin media uses fibre to the greenbox cabinet located every half mile or
so. From there is uses cheap coax to the home as two way, multi frequency
transmission media. Different frequencies carry different protocols.
Different protocols are used for different things. Tv streams, subscription
enablement, video on demand, tivo communication for ip streaming of online
content in a dedicated pipe to prevent really heavy internet usage affecting
bbc iplayer on tivo. telephone and internet use yet more frequencies.

Virgin media affectively keep the streams seperate and they can't interfere
with each other.

Bt has gone a different route with their 21st century network where
everything goes down a single pipe (except freeview which is still received
via ariel). Everything is controlled via quality of service where telephone
is likely very high priority and bittorrent is very low priority.

Bt are using copper to the exchange, with trials in newbuild areas of fibre
to the home. They are also enabling some other areas with fibre to the
cabinet.

The reality is electricity through copper and light through glass convey
signals at near enough the same speed.

Bare in mind that this is not the same as the how fast electrons move
through copper... its more a factor of how fast they react.

R



Please excuse brevity and pistakes this email was composed on a mobile
phone.

Thanks and best regards,

Richard
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