Le 2013-01-28 à 17:30, Ole Troan <[email protected]> a écrit : > Remi, > >>> I believe the prefix length > 64 should be allowed. >> >> >>> It is upto the >>> operator to choose the prefix length of their choice. >> >> Agreed. >> No one suggest to say the contrary. >> >> Yet, operators have the constraint of RFC 4291 that "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". > > I am not aware of any implementations that restrict the prefix length to 64. > I'm not aware of any implementation that applies any meaning to any bits in > the interface-id. > I'm aware of operators using prefix lengths longer than /64. > > actual deployment and implementation trumps text. that doesn't even use > RFC2119 language. > (and I know after annual discussions with one of the authors that the > intention with that line was not to make IPv6 classful.) > >> >> The draft says that: >> (a) The PSID is: >> +--+---+---+---+---+---+---+---+---+ >> |PL| 8 16 24 32 40 48 56 | >> +--+---+---+---+---+---+---+---+---+ >> |64| u | IPv4 address | PSID | 0 | >> +--+---+---+---+---+---+---+---+---+ >> (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: >> - What happens to the u octet? > > that's up to the operator. > >> - And to the IPv4 address if the prefix is longer than /68? > > it gets overwritten by the prefix, isn't that what the text says?
Partially overwritten, yes, thus creating confusion, for no known reason to justify it. I wonder what use of the IPv4 address could one imagine in this case? > > >> - ... >> >> 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. > > huh? > provider wants to deploy with a prefix length of 128? single tunnel end point > address. isn't that obvious? Obvious, no! Could you please complete an example with a CE address and its BMR? Thanks, RD > > cheers, > Ole _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
