I don’t know who wrote the BBC article about the YouTube blocking incident, but whoever it is seems to think that it has something to do with “faster” routes. (It doesn’t. c|net’s story explains what actually happened.)

I sent them a detailed message about correcting this, but the story currently still reads

“Essentially, Pakistan Telecom took over some of the net addresses assigned to YouTube. Crucially the path it offered to this group of addresses was faster than the usual one used by the hardware, or routers, that speed traffic around the internet. Pakistan Telecom let this address change propagate to the routers of one of its partners - PCCW. Routers are constantly in search of faster ways to get the data passing through them to its destination so news about this faster path started propagating across many of the net's routers.”

which is of course nonsense.

Edge routers don’t work by choosing “faster” routes. Most of their decisions are driven by the commercial dealings and network policies of their operators; only after those have been taken into account will they consider AS path length, which isn’t necessarily related to the number of hops a packet will take (e.g. because an AS may need to pass it between edge routers somehow), let alone the round-trip-time.

The problem was caused by Pakistan Telecom advertising a more specific route (i.e. a route to a smaller range of IP addresses) than the one advertised by YouTube. Had that advertisement remained within Pakistan, it would have been fine; unfortunately for whatever reason it was allowed to propagate out of Pakistan and into the wider Internet.