Hi Thomas, On Sun, 07 Nov 2010 14:29:16 -0500 Thomas Narten <nar...@us.ibm.com> wrote:
> The document currently says: > > Routers MUST support the assignment of /127 prefixes on point-to- > point inter-router links. > > I fully support this. > > However, I believe that as far as routing is concerned, IPv6 continues > to be based on CIDR. There is nothing special about the 64 boundary > from a routing perspective. This, I believe the above should be > changed to the following: > > Routers MUST support the assignment of arbitrary length prefixes > (including but not limited to /127s) on point-to-point inter-router > links. > > I do not see any reason to restrict implementations to only supporting > /127s prefixes. > > Thoughts? In particular, I'd like to hear from operators as to whether > they want the functionality of being able to assign subnets of > arbitrary length, or whether it would be sufficient to only support /127s. > if the goal of this draft is to fundamentally mitigate the ND cache exhaustion issue, by preventing the ping-pong issue when ND NS/NAs are switched off (as implementations are commonly doing on point-to-point links), then anything other than a /127 on a point-to-point link won't prevent the pong-point issue. > Note: I am quite aware that stateless addr autoconfiguration uses > 64-bit Interface Identifiers (IIDs) and that the addressing > architecture says that addresses need to be formed using IIDs. However > these requirements relate to the formation of addresses. I am aware of > no architectural requirement (or justification) that says routing > should only be done on the first 64 bits of an address, regardless of > how an address was formed. > > Note: This does not mean I am in favor of or am suggesting any changes > to stateless addr config, or the IPv6 addressing architecture. I > believe the above can be made without changing those documents. > I think the Addressing Architecture RFC would need to be changed, as it stipulates 64 bit interface ids, which I think implies a maximum of 64 bit prefix lengths, unless these /127s were only permitted within 0::/3 - the impacted text is in 2.5.1 of RFC4291 - "For all unicast addresses, except those that start with the binary value 000, Interface IDs are required to be 64 bits long and to be constructed in Modified EUI-64 format." Regards, Mark. -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
