Hi Jacni
2011/8/18 Jacni Qin <[email protected]>: > > On 8/18/2011 3:24 PM, Washam Fan wrote: >> >> Hi, >> >>>> It seems to me, when delegating CE ipv6 prefix, a longest match might >>>> be used. But when forwarding a IPv4 packet, a longest match is >>>> useless, because domain 4rd prefixes don't overlap. >>> >>> Why? Sorry, I don't follow. The domain IPv4 prefixes can overlap. >> >> if domain 4rd prefixes overlap, when a CE forwards a ipv4 package, it >> will get confused. because, let's say, two rules matched, it doesn't >> know which domain ipv6 prefix is used to build outer ipv6 destination >> address. > > There could be, > 1.{2408:db8:100::/40, 10.10.1.0/24, 48} > 2.{2408:db8::/32, 10.10.0.0/16, 48} > > just make sure that the ":100" + ".1.0/24" are excluded when assigning the > CPE IPv6 prefixes to CPEs which will select the second rule to calculate the > IPv4 prefixes. For traffics to these CPEs, longest match of IPv4 prefix will > work. > Got you now, thanks, washam > Cheers, > Jacni >> >> Thanks, >> washam >>> >>> Cheers, >>> Jacni >>> >>>> Thanks, >>>> washam >>>> >>>> 2011/8/17 Rémi Després<[email protected]>: >>>>> >>>>> Le 17 août 2011 à 03:10, Jacni Qin a écrit : >>>>> >>>>>> hi Remi, >>>>>> >>>>>> On 8/16/2011 4:27 PM, Rémi Després wrote: >>>>>>> >>>>>>> ... >>>>>>> As already discussed privately, I don't know realistic cases where >>>>>>> two >>>>>>> rules would have IPv6 or IPv4 overlapping prefixes. >>>>>>> Consequently, it seems that "longest" match, while being permitted, >>>>>>> doesn't need to be a requirement. >>>>>> >>>>>> If there are multiple ways for CPE to decide the IPv6 prefix, we have >>>>>> to >>>>>> specify the order of priority. e.g., firstly check if there is any >>>>>> implication assigned along with the rules, no? then choose the >>>>>> "longest" >>>>>> match. >>>>>> BTW, I think the longest match is not bad. >>>>> >>>>> It isn't bad, agreed, because it gives the same result as first match >>>>> when prefixes don't overlap. >>>>> It shouldn't however be made a _requirement_ if there is no well >>>>> understood use case because that additional complexity, small but real. >>>>> >>>>> Whether there may be realistic configurations where prefix overlap is >>>>> useful remains AFAIK an open question. >>>>> I have serious doubts, but no time now to argue in details. >>>>> IMHO, It's up to those who argue in favor of longest match to provide >>>>> at >>>>> least one realistic example (if there is one). >>>>> Then we will agree (or discuss). >>>>> Is that fair? >>>>> >>>>> Cheers, >>>>> RD >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> Softwires mailing list >>>>> [email protected] >>>>> https://www.ietf.org/mailman/listinfo/softwires >>>>> >>> > > _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
