[LINK] DNS outage?

Stilgherrian stil at stilgherrian.com
Wed Jul 29 09:02:06 AEST 2009

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.


Stilgherrian http://stilgherrian.com/
Internet, IT and Media Consulting, Sydney, Australia
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