The section on “reasons for using longer prefixes”, specifically: 5.2 <https://tools.ietf.org/html/rfc6164#section-5.2>. Neighbor Cache Exhaustion Issue
Intrigues me. How someone could exhaust my neighbor cache by targeting every address in my PTP /64 :) I dont think you really need SLAAC for PTP links anyway if you’re manually configuring those sorts of interfaces, which I do. Or I can just use link-local on internal PTPs. Other /64-ish features like RS/RA I don’t particularly need on PTP links. -c > On Jan 15, 2017, at 9:55 AM, Justin Wilson <[email protected]> wrote: > > But, as with anything, you have tradeoffs. > > Routers MUST support the assignment of /127 prefixes on point-to- > point inter-router links. Routers MUST disable Subnet-Router anycast > for the prefix when /127 prefixes are used. > > > Anything longer than a /64 will break SLAAC, neighbor discovery, and other v6 > “stuff”. If you don’t need these then a /127 is for you. Just know the > downsides of a /64 vs a /127. The RFC says you can do it, but it conflicts > with the before mentioned V6 stuff. Frankly I don’t care about conserving > IPV6 space. > > > > Justin Wilson > [email protected] <mailto:[email protected]> > > --- > http://www.mtin.net <http://www.mtin.net/> Owner/CEO > xISP Solutions- Consulting – Data Centers - Bandwidth > > http://www.midwest-ix.com <http://www.midwest-ix.com/> COO/Chairman > Internet Exchange - Peering - Distributed Fabric > >> On Jan 15, 2017, at 11:28 AM, Seth Mattinen <[email protected] >> <mailto:[email protected]>> wrote: >> >> On 1/15/17 8:08 AM, Justin Wilson wrote: >>> -assign a /64 for point to point links (aka the equivalent of /30s). >>> Again, don’t think in terms of host count. anything smaller than /64’s >>> breaks things. Some providers out there assign smaller blocks, but it >>> breaks things and isn’t RFC. Using a /128 is a hot debate at the moment. >>> Some folks are willing to live with the stuff that is broken. The whole >>> /127 or /128 debate came up due to security concerns mainly. >> >> >> Use of /127 on router links is RFC 6164 >> >> https://tools.ietf.org/html/rfc6164 <https://tools.ietf.org/html/rfc6164> >> >
