nanog mailing list archives
Re: IPv6: numbering of point-to-point-links
From: Blake Hudson <blake () ispn net>
Date: Mon, 31 Jan 2011 11:13:08 -0600
All of the (mostly religious) arguments about /64 versus any smaller subnets aside, I'm curious about why one would choose /126 over /127 for P-to-P links? Is this some kind of IPv4-think where the all-zeros and all-ones addresses are not usable unicast addresses? This isn't true in IPv6 (of course, it's not strictly true in IPv4 either). Is there another reason?
I setup a p2p /127 link and found that BGP would not peer over the link; Changing to /126 resolved the problem. I never looked into it further because I had intended to use /126 from the start. My guess is that while BGP should be a unicast IP, Cisco's implementation uses an anycast in some cases, disregarding the configured unicast address. Just one practical example...
Current thread:
- IPv6: numbering of point-to-point-links Lasse Jarlskov (Jan 24)
- Re: IPv6: numbering of point-to-point-links Carlos Friacas (Jan 24)
- Re: IPv6: numbering of point-to-point-links Grzegorz Janoszka (Jan 24)
- Re: IPv6: numbering of point-to-point-links Marco Hogewoning (Jan 24)
- Re: IPv6: numbering of point-to-point-links bmanning (Jan 24)
- Re: IPv6: numbering of point-to-point-links Jack Bates (Jan 24)
- Re: IPv6: numbering of point-to-point-links Crist Clark (Jan 24)
- Re: IPv6: numbering of point-to-point-links Owen DeLong (Jan 24)
- Re: IPv6: numbering of point-to-point-links Randy Bush (Jan 24)
- Re: IPv6: numbering of point-to-point-links Blake Hudson (Jan 31)
- Re: IPv6: numbering of point-to-point-links Randy Bush (Jan 31)
- Re: IPv6: numbering of point-to-point-links Blake Hudson (Jan 31)
- Re: IPv6: numbering of point-to-point-links Randy Bush (Jan 31)
- Re: IPv6: numbering of point-to-point-links bmanning (Jan 24)
- Re: IPv6: numbering of point-to-point-links Gary Buhrmaster (Jan 31)
- Re: IPv6: numbering of point-to-point-links Seth Mattinen (Jan 31)
- Re: IPv6: numbering of point-to-point-links Carlos Friacas (Jan 24)
- Re: IPv6: numbering of point-to-point-links Skeeve Stevens (Jan 24)
- Re: IPv6: numbering of point-to-point-links ML (Jan 26)