XO - a Tier 1 or not?

Justin M. Streiner streiner at cluebyfour.org
Tue Jul 28 15:30:47 UTC 2009

On Tue, 28 Jul 2009, Charles Mills wrote:

> Trying to sort through the marketecture and salesman speak and get a
> definitive answer.
> I figure the NANOGers would be able to give me some input.
> Is XO Communications a Tier 1 ISP?

Do the best of my knowledge, no.  The definition of 'Tier 1' is something 
of a moving target based on who you ask, but the most commonly stated 
criteria I've seen over the years are:
1. The provider does not buy IP transit from anyone - all traffic is moved
   on settlement-free public or private interconnects.  That's not to say
   that the provider doesn't buy non-IP services (IRUs, lambdas, easements,
   etc) from other providers on occasion.
2. The provider lives in the default-free zone, which is pretty much a
   re-statement of point 1.

I'll leave discussions about geographical coverage out of it for now.

That said, I don't think XO meets the criteria above.  I'm not 100% 
certain, but I don't think they're totally settlement-free.  Other 
providers like Cogent would fall into this bucket as well.

However, I also wouldn't get too hung up on tiers.  Many very reliable, 
competent, and responsive providers providers but transit to handle at 
least some portion of their traffic.  It also depends on what sort of 
service you need.  For example, if you need a big MPLS pipe to another 
country, there are a limited number of providers who can do that, so they 
would tend to be the big guys.  However, if you just need general IP 
transit, your options open up quite a bit.


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