Re: [ncrg] Network Complexity Research Group: Meeting in Paris

["Michael Behringer (mbehring)" <[e-mail]>]

Hi Paul, 

> -----Original Message-----
> From: Paul Mockapetris [mailto:[e-mail]]
> Sent: 21 January 2012 06:03
> To: Michael Behringer (mbehring); [e-mail]
> Subject: Re: [ncrg] Network Complexity Research Group: Meeting in
Paris
> 
> I live in Paris, so I'm expecting to attend.  This isn't really a
> proposal for an agenda item, though if it piques anyone's interest,
> I'm happy to discuss.
> 
> I have a question (not being a router person):
> 
> 1. BGP seems to be one of the the preferred lab animals for
> complexity folks, or at least the canonical example.
> 2. We have been hearing that scalability of the current routing
> system is a big problem (at least for core routers),
>     e.g. RFC 4984, not to mention NDN

Routing has been discussed, because it's what people in the room
understand. (My take)

Personally I'd be quite interested to hear thoughts on the complexity of
other systems as well, for example DNS (to pick a completely random
example ;-)   DNS works obviously very well, thus the complexity is
organised in a way that does NOT lead to catastrophic failures, thus my
feeling: We can learn something here. 
 
> Has anyone done a good description of the factors involved and their
> relationship?
> 
> i.e. simplistically
> 
> Cost_router=Cost_interfaces + Cost_Backplane + Cost_Route_Calculations
> 
> Cost_interfaces = K1 * Number_routes * Number_interfaces
> 
> Cost_Route_Calculations = K2 * Number-routes * log(Number-routes) *
> Updates_sec
> 
> etc, etc.

So Keith Jones did a lot of work on TCO, which I think is a quite neat
"metric" for complexity, if well done. (see soap box 3 on this page:
http://networkcomplexity.org/wiki/index.php?title=Agenda) 
This goes down the bits and pieces, but (afaik) doesn't look into the
cost of a route update though. Intuitively, a more complex routing
algorithm consumes more CPU cycles thus costs more. Probably however
this is too far from monetary cost to make sense to compare?

You find some random collection of thoughts on 
http://networkcomplexity.org/wiki/index.php?title=Definition

> Obviously, it will vary somewhat between IPv4 and IPv6 because
> addresses are bigger, and whether you are implementing a lot of VPNs,
> interface speeds, etc, etc.
> 
> But it seems like fundamental limits would lurk wherever there are
> exponential or superlinear or linear costs that would be good
> guidelines in system design.  The utility of the model would be to
> make it easier to think about the scaling properties of say, LISP vs
> NDN.

Something to elaborate on. Personally, I'd be quite interested to hear
your thoughts in more detail. Would you be prepared to do a presentation
at the NCRG?

Michael

> 
> At 05:42 PM 1/20/2012, you wrote:
> >Just a short note that the NCRG will have a meeting at the upcoming
> IETF
> >in Paris. The slot is not yet known.
> >
> >This is also a call for agenda items: If you would like to present
> your
> >work on network complexity, please let us know!
> >
> >See:
> >http://irtf.org/ncrg
> >http://networkcomplexity.org/
> >
> >Michael
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