nanog mailing list archives
Re: Choice of network space when numbering interfaces with IPv6
From: Franck Martin <franck () genius com>
Date: Sat, 16 Oct 2010 10:38:18 +1200 (FJT)
but then, can't we use ip unumbered on p2p links on cisco? ----- Original Message ----- From: "Mark Smith" <nanog () 85d5b20a518b8f6864949bd940457dc124746ddc nosense org> To: "Zaid Ali" <zaid () zaidali com> Cc: "NANOG list" <nanog () nanog org> Sent: Saturday, 16 October, 2010 10:21:03 AM Subject: Re: Choice of network space when numbering interfaces with IPv6 Hi, On Fri, 15 Oct 2010 12:26:13 -0700 Zaid Ali <zaid () zaidali com> wrote:
SO I have been turning up v6 with multiple providers now and notice that some choose /64 for numbering interfaces but one I came across use a /126. A /126 is awfully large (for interface numbering) and I am curious if there is some rationale behind using a /126 instead of a /64.
If you're not going to follow the IPv6 Addressing Architecture, which says /64s for everything, then the prefix length decision is pretty much arbitrary - there is nothing that special about /112s, /126s, /127s or /128s (or /120s or /80s) - they all break something in the existing IPv6 RFCs so once you've passed that threshold then you're really only choosing your poison. If you're going to go down that latter path, I'd suggest reserving a /64 for each link, and then using a longer prefix length out of that /64 when you configure the addressing, to make it easier if you decided to change back to /64s at a later time. Regards, Mark.
Current thread:
- Choice of network space when numbering interfaces with IPv6 Zaid Ali (Oct 15)
- Re: Choice of network space when numbering interfaces with IPv6 Jeroen Massar (Oct 15)
- Re: Choice of network space when numbering interfaces with IPv6 Scott Howard (Oct 15)
- Re: Choice of network space when numbering interfaces with IPv6 Nick Hilliard (Oct 15)
- Re: Choice of network space when numbering interfaces with IPv6 Zaid Ali (Oct 15)
- Re: Choice of network space when numbering interfaces with IPv6 Mark Smith (Oct 15)
- Re: Choice of network space when numbering interfaces with IPv6 Franck Martin (Oct 15)
- Re: Choice of network space when numbering interfaces with IPv6 Kevin Oberman (Oct 15)
- Re: Choice of network space when numbering interfaces with IPv6 Randy Bush (Oct 16)
- Re: Choice of network space when numbering interfaces with IPv6 Mark Smith (Oct 16)
- Definitive Guide to IPv6 adoption Brandon Kim (Oct 16)
- Re: Definitive Guide to IPv6 adoption Owen DeLong (Oct 16)
- Re: Definitive Guide to IPv6 adoption Joel Jaeggli (Oct 16)
- Re: Definitive Guide to IPv6 adoption Dobbins, Roland (Oct 16)
- RE: Definitive Guide to IPv6 adoption Brandon Kim (Oct 16)
- Re: Definitive Guide to IPv6 adoption Franck Martin (Oct 16)
- Re: Definitive Guide to IPv6 adoption Owen DeLong (Oct 17)
- Re: Choice of network space when numbering interfaces with IPv6 Mark Smith (Oct 16)