Marko is right. There are some security issues which limit the use of the /64, /127 can mitigates all security issues. Allocate /64 and use /64 for point-to-point when vendor fix there issues, until then configure /127 out of the /64 on each interface.
The following RFC can help understand the use of /127: draft-kohno-ipv6-prefixlen-p2p 2012/9/13 Marko Milivojevic <[email protected]> > Again, there are some sound reasons for it (which I can't remember > now), but I believe it has to do with the consistent assignment > policies. > > -- > Marko Milivojevic - CCIE #18427 (SP R&S) > Senior CCIE Instructor - IPexpert > > On Thu, Sep 13, 2012 at 8:16 AM, CJ Infantino <[email protected]> > wrote: > > What's the point of that? Is it to allow yourself to migrate back to a > > /64 in the event the /127 causes issues? > > > > CJ > > > > Sent from my iPhone > > > > On Sep 13, 2012, at 10:16 AM, Marko Milivojevic <[email protected]> > wrote: > > > >> There are some good reasons for it. The recommendation is still to > assign /64 blocks for p2p links, but configure them as /127. > >> > >> -- > >> Marko Milivojevic - CCIE #18427 > >> > >> :: This message was sent from a mobile device. I apologize for errors > and brevity. :: > >> > >> On Sep 12, 2012, at 14:22, Bal Birdy <[email protected]> wrote: > >> > >>> Marko which rfc references /127 recommendation? From my understanding > /64 are required to support NDP features, given you only have ie neighbor > this is a not pointless. So is this why they have moved away from the hard > and fast /64 everywhere rule. > >>> > >>> Thanks > >>> > >>> On Sep 13, 2012 7:17 AM, "Marko Milivojevic" <[email protected]> > wrote: > >>> I'm curious - why would you use /126 instead of RFC-recommended /127? > >>> > >>> -- > >>> Marko Milivojevic - CCIE #18427 (SP R&S) > >>> Senior CCIE Instructor - IPexpert > >>> > >>> On Wed, Sep 12, 2012 at 7:30 AM, Max Kamali <[email protected]> wrote: > >>>> Bal, > >>>> > >>>> I use /126s for point to point links (only) in production and they > work just > >>>> fine. Tuscany networks created a fantastic free IPv6 subnet > calculator, aka > >>>> TN IPv6 calculator. > >>>> > >>>> -max > >>>> > >>>> > >>>> -----Original Message----- > >>>> From: [email protected] > >>>> [mailto:[email protected]] On Behalf Of Bal Birdy > >>>> Sent: Wednesday, September 12, 2012 3:41 AM > >>>> To: [email protected] > >>>> Subject: [OSL | CCIE_RS] Stupid question time - IPV6 VLSM > >>>> > >>>> Ok I know that it's stipulated that IPv6 should be a /64, and never > really > >>>> change, but I came across some slides talking about using /126 or > /127s for > >>>> point to point links (which sparked a discussion at work). Thinking > along > >>>> the lines of the /30 concept with IPv4, for arguments sake, if I > wanted to > >>>> work out what IP addresses I can manually configure on either end of > my p2p > >>>> link, that's using IPv6, am I right in saying I use the same approach > as > >>>> with IPv4 for working out the IP addresses. > >>>> > >>>> So if I say a /126 is - 1111111111111100 in binary. The last two bits > give > >>>> me networks of 0,4,8 and so on. with usable ip's of 1,2 and 3. Now > the 3 > >>>> comes into play as there's no concept of broadcast in IPv6 (!?), so > why do > >>>> we need the broadcast IP as previously required for IPv4??? > >>>> > >>>> Is this technically correct? > >>>> > >>>> Thanks > >>>> Bal > >>>> _______________________________________________ > >>>> For more information regarding industry leading CCIE Lab training, > please > >>>> visit www.ipexpert.com > >>>> > >>>> Are you a CCNP or CCIE and looking for a job? Check out > >>>> www.PlatinumPlacement.com > >>>> > >>>> http://onlinestudylist.com/mailman/listinfo/ccie_rs > >>>> > >>>> _______________________________________________ > >>>> For more information regarding industry leading CCIE Lab training, > please visit www.ipexpert.com > >>>> > >>>> Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com > >>>> > >>>> http://onlinestudylist.com/mailman/listinfo/ccie_rs > >> _______________________________________________ > >> For more information regarding industry leading CCIE Lab training, > please visit www.ipexpert.com > >> > >> Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com > >> > >> http://onlinestudylist.com/mailman/listinfo/ccie_rs > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
