Katrina Network Damage Report

Sun Sep 11 10:52:37 UTC 2005

 love IPv6 more than you guys would ever give to a sole. Shoot I could run a 
big ISP on a single 48. God bless America.

Bring it on... Why are you so afraid?

---
Alan Spicer (a_spicer at bellsouth.net)
----- Original Message ----- 
From: "Steve Gibbard" <scg at gibbard.org>
To: <nanog at nanog.org>
Sent: Sunday, September 11, 2005 12:35 AM
Subject: Re: Katrina Network Damage Report

>
> On Sat, 10 Sep 2005, Todd Underwood wrote:
>
>> interesting discussion.  at least we're talking about networking now.
>> :-)
>>
>> wrt sean's comment, the only thing i can think he means by 'partition'
>> is that the networks may have power may be in some routing table but
>> just not the routing table of any of renesys's (or routeviews or ripe)
>> peers.  in that case, i guess i would agree.  our use of 'outage' is a
>> special case of 'partition' where the whole internet is on one side
>> and it's possible that the networks in question are on the other.
>> they may route somewhere.  just not to the internet.
>
> The difference between a partitioning and a complete outage can depend a 
> lot on what's on each side of the partition.
>
> If my DSL line goes down, I suppose that's technically a partitioning.  I 
> can still get to the DNS server in the basement, or to my neighbors' 
> computers on my wireless network, but not to anything else.  Meanwhile, 
> the rest of the Internet can't get to anything in my or my neighbors' 
> houses, but is otherwise functional.  Complaining that that was anything 
> less than a complete outage would be at best extremely pedantic, since 
> there's likely nobody on my home network who particularly cares about 
> being able to get to other things on my home network.
>
> However, the same sort of partitioning can happen on a much bigger scale. 
> There are some countries or large regions that have several ISPs, an 
> exchange point they use to connect to eachother, locally hosted content, 
> and a single path out to the rest of the world.  In those areas, it's 
> possible for the international link to fail but for connectivity to the 
> nearby portions of the Internet to work fine.  In those cases, it's far 
> less clear-cut to say, "they don't have access to the Internet," and might 
> be more accurate to say that their part of the Internet had been cut off 
> from the rest of the Internet.
>
> (I gave a talk on this at NANOG and a few other conferences last spring. 
> The associated paper is at 
> http://www.pch.net/resources/papers/Gibbard-mini-cores.pdf)
>
> From what I understand of the Renesys methodology, the difference between 
> a partitioning and a total outage wouldn't be visible.  A router in a 
> region that wasn't able to send data to Florida wouldn't be able to send 
> data to your collector (which doesn't mean the Renesys system isn't really 
> cool for answering all sorts of other questions -- it is).
>
> That said, I haven't heard any reports of a large scale partitioning 
> happening in New Orleans.  It sounds like most of what was down was down 
> due to local infrastructure being under water or without power, so my 
> guess is that the Renesys view was pretty accurate in this case.  Thanks 
> for sharing it.
>
> -Steve
>
>
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