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noggin11,936 posts since 26 Jun 2001
You would expect redundant main and reserve circuits routed via different geographical routes to be used for ITN contributions to ITV surely?

You would also expect them to be routed via independent routers (or at least salt and peppered input/output cards) to minimise single points of failure. I'm sure someone can find a SPOF if they look hard enough though...

(In most BBC studio operations the sound desk is still a SPOF - backup mini-sound desks are no longer being installed AIUI - though modern sound desks have a high degree of redundancy engineered in I suppose. Vision mixers are usually backed up by an emergency cut, there is usually a TX path that can bypass a router, and lighting usually have backup stores to allow a known good DMX salvo to be sent to all lamps to set up a basic plot)
Markymark4,178 posts since 13 Dec 2004
Meridian (North) South Today
Salt and peppered?


A station router will typically have several hundred inputs and outputs. You can route
any single input, to any single, or multiple collection of destinations.

Typically the router will be made up from a series of 16, 24, or 32 input and output cards

For instance a 512 x 512 router might have Qty 16 32-input cards, and 16 output cards.

If a card should fail, you lose (in this example) a bunch of 32 inputs or outputs. So, you spread important sources and destinations across several cards.

It doesn't give 100% resilience, unless you also have redundant crosspoint and CPU cards (Crosspoint cards do the actual routing, and the CPU is the router's brain)

Further reading

http://www.snellgroup.com/products/routing/routing-overview/overview

(Other router manufacturers are also available)
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Telly Media and elmarko gave kudos