nanog mailing list archives
Re: AS Path Loops in practice ?
From: David Barak <thegameiam () yahoo com>
Date: Thu, 11 Dec 2003 20:44:05 -0800 (PST)
--- "Stephen J. Wilcox" <steve () telecomplete co uk> wrote:
Most (all) large ISP's have a "customer ASN".This allows a customerto connect in multiple places, run BGP, and getsomething approximatingreal redundancy to that carrier. However, ratherthan allocate oneASN to each customer, all customers use the same"customer ASN".Yes, that means they must default to the provider(and/or have theprovider provide a default route) to reach theother customers usingthis technique.Perhaps I'm missing something having not done this myself but why arent the customers just using private ASNs? That would also remove the 'must default' clause. Steve
1) It would only remove the "must default" clause if the provider either stripped (or overrode) the local-as, or if all of the private ASNs were unique. That is a big headache. 2) Private ASNs are not, per RFC1918, supposed to be connected to the Internet, in much the same way that private IP space is not supposed to be connected to the Internet. This can also be solved by stripping/overriding. 3) One advantage of using a public, albeit common, customer ASN is that if a customer has RIR-allocated space, those IPs will make it onto the global table, and will not suffer the filtering which may be present for the provider's own routes. ===== David Barak -fully RFC 1925 compliant- __________________________________ Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing. http://photos.yahoo.com/
Current thread:
- Re: AS Path Loops in practice ?, (continued)
- Re: AS Path Loops in practice ? Robert E. Seastrom (Dec 08)
- Re: AS Path Loops in practice ? Joe Provo (Dec 08)
- Re: AS Path Loops in practice ? Robert E. Seastrom (Dec 08)
- Re: AS Path Loops in practice ? Joe Provo (Dec 08)
- Re: AS Path Loops in practice ? Ben Crocker (Dec 09)
- Re: AS Path Loops in practice ? Niels Bakker (Dec 09)
- Re: AS Path Loops in practice ? Leo Bicknell (Dec 09)
- Re: AS Path Loops in practice ? Niels Bakker (Dec 09)
- Re: AS Path Loops in practice ? Stephen J. Wilcox (Dec 11)
- Re: AS Path Loops in practice ? Leo Bicknell (Dec 11)
- Re: AS Path Loops in practice ? Jeff Aitken (Dec 11)
- Re: AS Path Loops in practice ? David Barak (Dec 11)
- Re: AS Path Loops in practice ? Stephen J. Wilcox (Dec 12)
- Re: AS Path Loops in practice ? David Barak (Dec 12)
- Re: AS Path Loops in practice ? Niels Bakker (Dec 09)
- Re: AS Path Loops in practice ? Robert E. Seastrom (Dec 08)