[LINK] DNS outage?

Kim Holburn kim at holburn.net
Wed Jul 29 17:51:50 AEST 2009

On 2009/Jul/29, at 1:02 AM, Stilgherrian wrote:
> On 29/07/2009, at 8:39 AM, Jan Whitaker wrote:
>> What ever happened to the Internet rerouting itself so it 'can't be
>> broken'? Or was that always a myth? I thought its resilience was one
>> of its big selling points.
> That re-routing is what BGP does: Border Gateway Protocol is the
> routers talking to each other to indicate which are the best routes
> for traffic to follow.
> But... it depends on what scale you're looking at things.
> If you look at the heavily cross-links nexus between major ISPs in one
> city, then yes there will be re-routing when a single router fails.
> But if a ship's anchor breaks a major fibre link, and it's one of only
> three or four links into a country, then bang! There goes a
> significant proportion of your capacity, because there isn't anywhere
> else for it to be routed. Everything gets slowed
> Dig up the 200-pair copper cable that's running down your street, and
> the whole suburb gets blacked out completely. There is NO redundancy
> at that level. Or at many other points.
> "The Internet" isn't one thing that's of equal reliability or
> redundancy. It's a patchwork of many, many disparate networks held
> together with string and Blu-Tak. It's a wonder the damn thing works
> at all.

I have wondered for a long time why it's called a "net".  The  
underlying topology of the "net" for a very long time has been a star  
or galactic topology with the main centre in the US.  I think that's  
gradually changing but for a long time most packets from or to  
Australia went through the US.  If you have a topology like that it's  
not going to be able to reroute if something near the centre goes wrong.

2008 and still most of our traffic goes through the US hmmm:


Kim Holburn
IT Network & Security Consultant
Ph: +39 06 855 4294  M: +39 3494957443
mailto:kim at holburn.net  aim://kimholburn
skype://kholburn - PGP Public Key on request

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