tiers?

Fri Jul 18 16:53:36 UTC 1997

Interesting Tier 1.  You'd only have 2 Tier 1s in this case, MCI with
their OC12 backbone and Sprint with their OC3 backbone.  UUNET, ANS, BBN
(the other big three) operate a DS3 backbone--UUNET is not yet at OC12 to
the best of my knowledge.  Put things into persepective.
> 
> A number of ISP's and backbone providers (national and international) all
> colocate on our facilities.  One of the most asked questions I recieve from
> everyone is the question asked regarding Tiers.  I have come up with IMHO a
> response to them that seems to be well accepted.  Now I'm not saying this
> is true in all instances, but it seems acceptable.
> 
> I define a Tier 1 network as a company who has a robust OC3 backbone and
> peers at a majority of the major NAPs (and private peering) in the U.S. and
> around the world.  Now, this OC3 backbone should not only go East to West
> but North to South,be somewhat fault tolerant, and provide reasonable
> connectivity to ISP's throughout the country and serve as gateway
> connections to international backbone ISPs.  If you use this loose
> definition of Tier 1 network, you see immediately you have the big 10 or 15
> who are very selective in choosing their peering partners.
> 
> A Tier 2 network could be defined as a DS3 backbone (maybe with some OC3
> but a majority DS3) who would have a large amount of bandwidth East to West
> or North to South but does not have as large a communications
> infrasturcture or network mesh as a Tier 1 provider.  These companies would
> peer at some of the major NAPs (plus private peering) but would also appear
> as many of the other exchange points where the Tier 1 providers wouldnt
> bother appearing.  These Tier 2 players may peering with some ot the Tier 1
> but not all of them.  Or even if they should because their network is not
> as robust as the Teir 1 they would fall into the Tier 2 catagory.
> 
> A Tier 3 network provider I consider to be a Regional backbone company.
> This is a company to has a minimum of a 10 meg backbone within a region.
> This is a company who is providing transit services to other smaller ISPs
> within his region.  He may connect at some of the regional exchange points
> or conduct private peering with other Tier 3 providers in his area.
> Typically this level network would not peering with a Tier 1 at all and
> most Tier 2 providers will not peer either.
> 
> Below Tier 3 are the ISP ranks, or smaller ISPs.
> 
> Using this type of philosphy for defining Tiers could work with the U.S.
> Domestic network providers but falls apart when you begin looking at a
> global view.  There are companies who would be considered a Tier 1 provider
> within their own country but when they run their own bandwidth to the U.S.
> they are often times considered a Tier 2 or lower Tier network when looking
> for peering partners.  As such they are often forced to purchase transit
> from the U.S. Tier 1 or 2 providers.  With this there is still an
> inequality when trying to apply a Tier structure on an international basis.
> There is no throught to the cost of the communications lines and and
> sometimes the benefit that can be derived through a peering process with
> international backbone networks (those with DS3 international lines).  I'm
> not saying this is true in all instances, but it appears to the the norm
> rather than the exception.
> 
> I think, IMHO, that by using this approach, combining both the size of the
> physical network, technology and peering provides a starting point for
> looking at or trying to define a Tier Structure.  Will this work in all
> cases??? I doubt it because there are always exceptions.  But it is a
> starting point for looking at networks from a global view.
> 
> Rick
> Telehouse America
> (718)355-2559
> 
> P.S.  The opinions present above are personal and in no way reflect the
> views of Telehouse....:)
> 
>