Honest Cogent opinions without rhetoric.
peterattelia at gmail.com
Wed Mar 8 13:34:53 UTC 2006
On 3/8/06, Todd Underwood <todd-nanog at renesys.com> wrote:
> On Wed, Mar 08, 2006 at 01:56:00AM -0500, alex at pilosoft.com wrote:
> > (from Marty)
> > > From a global perspective, the top 12 (I stopped at Cogent since you
> > > are asking about them) service providers whose customers and peering
> > > partners reach the largest number of networks are listed below. You can
> > > make some fairly interesting assumptions on your own:
> > <snip>
> > This gotta be the most meaningless metric ever. What does "reach"
> > mean?
> now, that's a bit harsh. 'incompletely specified in this email',
> perhaps, but 'meaningless'? come on. :-)
> the marketing description for those rankings is: "Identify service
> providers who are responsible for meeting Internet transit needs
> (directly or indirectly) of significant numbers of large customer
> networks within a given market, including both customer and peering
> in actual, technical detail, what that means is that we take global
> routing data (routeviews-style), determine the relationship of every
> edge (customer, provider, peer), and weight the 'downstream cone' (a
> caida term that is useful here) of each provider by the scaled prefix
> space and the degree to which that provider actually provided transit
> to that prefix space over the course of time. it's critical to
> integrate across time and across lots of peers in this process.
> otherwise, the position of your peers and leaks come to dominate the
> this metric (one of several that we've begun calculating daily) isn't
> perfect, but we've found that for large SPs it matches expectations of
> people familiar with traffic flows.
> > Note that many Cogent customers, while using Cogent for outbound, prefer
> > not to announce any routes to Cogent for political reasons (or prepend or
> > depref their routes). So, that metric won't be exactly helpful.
> this is, in fact, a useful point. detecting and compensating for
> asymmetric routing is difficult in a metric such as this, although
> it's probably not impossible.
> todd underwood +1 603 643 9300 x101
> renesys corporation chief of operations & security
> todd at renesys.com http://www.renesys.com/blog
What i would do is construct an RFP with specific questions about
capacity, availability and locations (plus other things i can't
remember right now) so that I knew what i was getting into with any
provider on if they were congested. We see them all the time for
large deals, and i'm sure other providers do too. A decision to
purchase from supplier A vs. B should not be done lightly, and without
some due diligence pertaining to where YOUR traffic may be coming from
or going to. Perhaps a spread sheet of some sort that allows you to
consolidate all the responses.
Good Luck Peter Cohen
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