Le 15 oct. 2010 à 11:14, Dong Zhang a écrit : > Hi Remi, > > The IPv6 host address is directly obtained by an indication message from the > 6a44 server. Here is the format of the IPv6 address. > +-------+-------+-------+-------+-------+-------+-------+-------+ > | ISP 6a44 prefix (D) | Customer IPv4 |NAT ext| Host IPv4 | > | | address (N) |port(Z) | address > (A) | > +-------+-------+-------+-------+-------+-------+-------+-------+ > According to the draft, N:Z is the address and port used on the CPE NAT44's > external side. > _ .-------. > Host / \ CPE / \ 6a44 Relay > +------+ . IP . +-----+ . IPv4 . +-------+ IPv6 > |6a44-C|--| no |--|NAT44|---| Provider |--O 6a44-S|-- network > +------+ . NAT . +-----+ . network . +-------+ > ^ ^ \ _ / ^ \ / | ^ > | A | '---.---' | | > | A:W <-> N:Z | | > | | | | > | | | | > | <- - - - - IPv6/UDP/IPv4 - - - - - -< | > | | > | | > < D.N.Z.A (/128) - - - - - - - -IPv6 - - - - < D (/48) > > Is the A:W<->N:Z mapping created staticly? Or dynimicly?
Dynamically when the 6a44-C starts operation. It then remains static until the 6a44 client or the NAT is reset. > When the host reqests the IPv6 address to the 6a44 server, the server gives > the host IPv6 address and liftime directly. If the mapping on the CPE is > allocated dynamically, how does the lifetime of the allocated host IPv6 > address will be set? An ISP that doesn't plan any customer renumbering can give this lifetime a very large value. It is only when a renumbering is planned that, a short lifetime is useful. > I mean this lifetime should longer than the expire time of the mapping on the > CPE. It is because if the mapping is deleted first and the host still uses > the IPv6 address embeded N:Z. It will arise problem. For instance, the CPE > may allocate another port, A:W<->N:Y. > > Therefore, there may be two ways to solve this. > a) set the lifetime of the allocated host IPv6 address shorter than the > expire time of CPE NAT44. Thus, the host is able to re-request its IPv6 > address within the NAT mapping expire time. The host ensures that its current NAT44 mapping is maintained with the same timeout as SIP for the same purpose (see in section 6 - the "Waiting for having to refresh the NAT-binding" state.) This is expected to be enough. Actually, it is still unclear to me whether the lifetime in IPv6 Address Indication is useful enough to keep its presence. Since the NAT-binding-refresh time of 29 seconds is already rather short, compared to the timing of renumbering operations, I would be interested in views of others on this. Regards, RD > b) require the CPE comply with endpoint-independent mapping in > RFC4787,RFC5382. But for this behavior, the premise is the host re-send the > address request message must use the same source address and port, A:W. Thus, > the NAT can provide the same N:Z. > > I suppose this should be clarified in 6a44 draft, if I am correct and not > missing someting. > > > Thanks. > > > > > 2010-10-15 > Dong Zhang > _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
