the Internet Backbone

Avi Freedman freedman at
Mon Apr 8 15:25:56 UTC 1996

> > Top level (Tier 1):
> >     -- provide transit as their principal business
> >     -- have at least some default-free routers
> >     -- have connectivity at >1 geographically separated major exchange
> >     -- need special measures to deal with BGP scaling issues inside
> >        their AS (or multiple AS) such as confederations, clusters, etc.
> 	Is this "on" the Internet or is it "the" Internet?
> 	(btw, I still take exception to the term default-free.  Taken
> 	 at face value, its just about as credible as a prior poster
> 	 who claimed that the tail end of his 28.8 modem was the internet
> 	 backbone. Proxy Aggregation is presuming some level of default
> 	 behaviour and needs to be considered as such.)

I understand your point re: default routing, but:
Default-free is still a useful distinction and is easy to see.
If you are a customer of a provider, you can easily traceroute to
a nonexistant IP address and see at what router it stops.

Now, many 2nd level providers that *could* operate default-free choose
not to.  Even if you have three or more sets of 30k+ routes each, it
takes balls to risk dropping packets that your customers want you to 
deliver just so that you can have the packet be dropped at your router
instead of at your (possibly backup) transit provider's router.

> --bill


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