About the address allocation convention between ISPs

Teng Fei tfei at ipanema.ecs.umass.edu
Wed Jun 4 13:11:12 UTC 2003

Dear Mr. Wayrynen,

Thank you very much for your reply.  What do you mean by "unnumbered
interfaces"?  Also  could you please confirm my question that if the
customer's address block  was not obtained from the provider, it is also a
convention that the  provider will provider the /30 address for the
inter-domain link?

>From the replys, it seems to me that there is no way to tell which
link is indeed the inter-domain link, if the two ASes are peers.  But for
customer-providers, I can guess with confidence.  Could I get these
information from the IPSes' or PoP's website, about who are their
customers/peers?  And how exactly the addresses were assigned?



On Mon, 2 Jun 2003, Darin Wayrynen wrote:

> Hi Teng,
> >From my experience it is standard practice for the provider of the
> Internet connectivity to provide the /30 network IP addresses for
> connectivity between two networks.
> There are exceptions such as when using unnumbered interfaces, peering
> points that share a common subnet between multiple ISPs, and when two
> networks flip a coin on private peering interconnects (where generally
> neither side is the provider to the other) to determine who is going
> to provide the interface IPs.
> Darin
> >
> > Hello everyone,
> >
> > I have a question about the convention of address allocation between ISPs.
> > If a smaller ISP tries to establish connection with its provider, does
> > this small ISP configure one of the interface on its boarder router using
> > an IP address obtained from the provider, or it is the other way around,
> > that is, the provider uses one of the IP address belongs to the customer
> > to configure the provider's boarder router?
> >
> > I have this question because I am trying to identify the link between two
> > organizations from traceroute measurements.   How the addresses are
> > allocated will affect the identification of the inter-domain link by
> > exactly one hop.
> >
> > I am not sure if there is such a convention at all, or the address
> > assignment is randomly decided according to the agreement between the
> > customer and the provider?
> >
> > Since I know there are many seasoned network professionals on this mailing
> > list, I think it might be a proper question to ask here.  Would anyone
> > kindly be willing to share your experience?  Thank you very much!
> >
> > Sincerely
> >
> > Teng
> >
> >
> >
> >

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