On 1/28/13 12:56 PM, "Ole Troan" <[email protected]> wrote:
>Senthil, > >[...] > >>> The draft says that: >>> (a) The PSID is: >>> +--+---+---+---+---+---+---+---+---+ >>> |PL| 8 16 24 32 40 48 56 | >>> +--+---+---+---+---+---+---+---+---+ >>> |64| u | IPv4 address | PSID | 0 | >>> +--+---+---+---+---+---+---+---+---+ >> >> I believe this figure is misleading by placing the IPv4 address in a >>fixed >> location. Figure 3 and Figure 7 >> In the draft shows that the IID is not in a fixed location. Also, the >>text >> surrounding the above figure 8, says >> "The Interface identifier format of a MAP node is based on the format >> specified in section 2.2 of [RFC6052], with the added PSID field if >> present, as shown in figure Figure 8." >> >> >> But RFC 6052 doesn¹t have the IPv4 address in a fixed location as per >> section 2.2. So I think this figure is misleading. > >perhaps we should just remove the RFC6052 reference then? >with a 48 bits of PSID + IPv4 address. >I don't mind if it is just IPv4 address, but then someone need to drive >that discussion. I think the above figure should be clarified as an example when the prefix-length+EA <= 64. If the prefix length is greater than 64, the IPv4 address appears after the prefix length and U bits are overwritten. If we clarify the above two points and remove the reference to rfc6052, that would be fine. Thanks Senthil > >> | n bits | o bits | s bits | 128-n-o-s bits | >> +--------------------+-----------+---------+------------+----------+ >> | Rule IPv6 prefix | EA bits |subnet ID| interface ID | >> +--------------------+-----------+---------+-----------------------+ >> >> >>> (b) "If the End-user IPv6 prefix length is larger than 64, the most >>> significant parts of the interface identifier is overwritten by the >>> prefix." >>> >>> This is particularly unclear: >> >> True. >>> - What happens to the u octet? >> >> I guess that needs to be made clear in the draft. We struggled with that >> in our implementation. > >if we remove the 6052 reference, there is no u-octet. > >>> - And to the IPv4 address if the prefix is longer than /68? >>> - ... >>> >>> Of course, if a use case is provided where MAP-E would be actually used >>> with an IID shorter than 64 bits, it should be discussed. But: >>> - There is no such use case so far. >>> - Looking for one doesn't seem useful. >> >> I would like to see the IPv4 address be present from bits 96-127, no >>need >> for the PSID to be repeated again. That would allow us to go upto /96 >>and >> being consistent with RFC 6052 which allows one to configure a prefix of >> upto /96. > >just put the IPv4 address in the bottom bits, and allow it to be >overwritten by the prefix. >it is just there for 'pretty printing' anyway. > >cheers, >Ole _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
