the Internet Backbone

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1

> 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

Avi

2

Can't anyone who takes full routes from any tier 1 provider
operate without a default route? And isn't it a reasonable assumption
that if you don't have a route somewhere, odds are they don't have a
route to you (assuming you do your own BGP routing) and so a default
route is mostly pointless anyway?

  What am I missing?

  DS

3

> 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.
>
> Avi

  Can't anyone who takes full routes from any tier 1 provider
operate without a default route? And isn't it a reasonable assumption

Yes

that if you don't have a route somewhere, odds are they don't have a
route to you (assuming you do your own BGP routing) and so a default

Yes/No

route is mostly pointless anyway?

Ok, why look through 30K routes instad of just sending all packets out the
default.

  What am I missing?

A lot.

Nathan Stratton CEO, NetRail, Inc. Tracking the future today!