North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: Routescience?

  • From: Mike Lloyd
  • Date: Tue Aug 21 21:08:07 2001


Jonas Luster wrote:
> * Sean Finn sez:
> > The RouteScience PathControl product which was announced
> > today
> >
> >  - supports active and/or passive measurements
> What does that mean in 'non-buzzword' speak? In other words, if you'd
> talk to someone who's actually seen a router at one or two occassions,
> what would you tell him/her?

A quick description is that PathControl optimizes the BGP decisions for
a multihomed organization.  It passively measures performance over all
egress paths, in a manner described below.  If active measurement to
selected destinations is required, it can be configured, but we view
that as strictly a supplemental source of data.  An organization would
only actively probe endpoints who agree to such exchange; typically,
that might involve remote offices or B2B partners. (Ideally, one
PathControl would talk to another.)  

Bottom line: PathControl does not automatically send unsolicited test
packets to anyone.

> Is this YAPM (yeat another ping misuse), ROTEG (route optimization
> through esoteric guessing) or something completely new such as (cough)
> Gibsons 'nano-probes'?

IMHO, it's NOTA. (None Of The Above); but a more detailed description is
called for ...

> So, if I am, say, yBay, a large used panties and fake celebrity
> autograph auction house, how would I, given the diversity of my 
> clients, do any optimization?

The details of the measurement method were written up in Network World
yesterday; see

In short, the PathControl device serves a component of HTML content,
and by watching the detailed TCP behavior, it gains information on
the end to end latency and loss characteristics of every path out of
the organization.  

The measurements are tailored to the NLRIs an organization actually
uses.  We find that this greatly cuts down the number of updates we must
send to deliver effective results.  Few "stub" organizations talk to
even 10% or 20% of the full table at a time.

PathControl then offers advice in the form of BGP updates to the edge
routers.  The prefixes, the rate of change and the factors to optimize
can be constrained, between CLI commands on PathControl and the
conventional filtering offered within BGP on the edge routers.  (FWIW,
PathControl marks any updates it sends with NO-EXPORT, as one more part
of ensuring that the changes are not propagated outside the AS.) 

Obviously, I'd be more than happy to discuss this further; off-list may
be a better context for any really detailed conversation.

Mike Lloyd
CTO, RouteScience