Fw: Where is the edge of the Internet?
Tim Griffin
griffin at research.att.com
Wed Nov 6 16:01:06 UTC 2002
Paul Vixie wrote:
> here's what i came up with while trying to explain "the edge" elsewhere.
> 1 - Connection Taxonomy
> 1.1. The Internet is a "network of networks", where the component
> networks are called Autonomous Systems (AS), each having a unique AS
> Number (ASN).
Even if this reflects the original intent of ASNs, it certainly does not fit
current reality. Let's call any set of networks under a unified administrative control
an Autonomous Routing Domain (ARD). ARDs should not be confused with ASes (an
implementation detail). They are distinct for these reasons:
1) Most ARDs do not have an ASN -- they are statically routed "at the edge".
2) Many networks "at the edge" use private ASNs.
3) Many ARDs share a provider provided ASN -- RFC 2270.
4) Many ARDs are implemented with multiple ASNs. Internap is probably an extreme
example. But even UUNet's global ARD (AS701, 702, 705 ...) reflects an implementation
choice (one that Sprint does not seem to follow with 1239, for example).
---tim
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