the Internet Backbone

Curtis Villamizar curtis at
Tue Apr 9 03:49:16 UTC 1996

Some nits.

In message <[email protected][]>, Howard C. Berkowitz writes:
> Here are my first thoughts on a tiered model, with attributes of each tier.
> Top level (Tier 1):
>     -- provide transit as their principal business

principal IP business (some people provide voice services or do other

>     -- have at least some default-free routers

Span at least one continent with default-free routers.  Are able to
provide customers with default free routing as an option.

>     -- have connectivity at >1 geographically separated major exchange

Yes.  And span these with default free routers (ie: taking full
routing at two routers and defaulting in the middle doesn't count).

>     -- need special measures to deal with BGP scaling issues inside
>        their AS (or multiple AS) such as confederations, clusters, etc.

or multiple AS to deal with scaling... but if a really hefty router
comes along or we ever are able inject AS paths into the IGP, this no
longer applies.

How about connection speed?  At least a DS3 backbone?  A redundant
backbone (no single circuit failure can partition the provider)?

Can we squeeze in 1.5:

    -- provide transit as their principal business
    -- have at least some default-free routers
    -- have connectivity at >1 geographically separated major exchange
    -- do not have a default free backbone
    -- maybe cannot provide full routing to all but a few customers
    -- maybe not redundant DS3s

Nobody in particular in mind here.

> 2nd Level
>     -- provide transit within a geographic area
>     -- may have default-free routers
>     -- limit operations to a geographic area; may connect to multiple
>        exchanges within that area

Connection speed?  Is Nearnet (mostly New England) circa 1994
equivalent to some small provider with two T1s and a bunch of routers
in a limited geographic region?  Again, having an providing full
routing is a big factor too.

> 3rd Level
>     -- do not provide commercial transit services, although
>        they may incidentally provide transit among their customers
>     -- do not do BGP peering with any "downstream" organizations.
>        Their user base is part of their AS.
>     -- May peer with multiple upstream providers
> 4th Level
>     -- do not run BGP
>     -- Internet access through provider only

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