Leaf, > http://datatracker.ietf.org/doc/draft-murakami-softwire-4rd/?include_text=1 > > Section 4 > > The IPv4 prefix, IPv4 address or shared IPv4 address for use at a > customer site is created by extracting the IPv4 embedded address (EA- > bits) from the IPv6 prefix delegated to the site. … > > A mapping rule consist of the following elements: a Domain IPv6 > prefix and prefix length, a Domain 4rd prefix and prefix length, CE > IPv6 Prefix length, and a Domain IPv6 suffix and length. … > > Section 4.1 > > The only remaining provisioning information the CE requires in order > to calculate the 4rd address and enable IPv6 connectivity is an IPv6 > prefix for the CE. This CE IPv6 prefix is configured as part of > obtaining IPv6 Internet access (i.e., configured via SLAAC, DHCPv6, > DHCPv6 PD, or otherwise). > ---------------------------------------------------------------------------------------- > > Q1. Per the above description, the EA-bits of CE IPv6 prefix sounds from > IAPrefix (option 26) of IA_PD (option 25) in DHCPv6. And the length of CE > IPv6 prefix sounds a different one with the length of IAPrefix. Will the > length of CE IPv6 prefix + the length of Domain IPv6 suffix = (be equal to) > the length of IAPrefix?
no, the CE IPv6 prefix is the prefix delegated to the site. typically this is done with DHCPv6 and those prefixes are equal. > ---------------- > Section 5.1.1 > > <----------- CE IPv6 prefix (max 128) --------------> > +-------------------------------+------------------------+ > |Domain IPv6 prefix | EA-bits | > +-------------------------------+------------------------+ > ... > Figure 1: From a CE IPv6 Prefix to a CE 4rd Prefix > > Section 5.1.4 > > ... > Domain IPv6 suffix > | > +- - - - - - - -----------+- - > ------+--|-+----------------------------------+ > |Domain IPv6 prefix| EA-bits| ' | 0 | > +- - - - - - - -----------+- - > ------+----+----------------------------------+ > <- - - - - ------- max 64 ------------> > <- - - - - ----------------- CE IPv6 address (128) ---------------------> > > Figure 4: From 4rd Prefix to IPv6 address (shared IPv4 address case) > -------------------------------------------------------------------------------------- > > Q2. There is a conflict in Fig.1 with Fig.5. I guess there is a typo in > Fig.1. The max. length of CE IPv6 prefix sounds 64, right? in theory it could be any prefix length. up to 128. > Q3. BTW, what is the design purpose of Domain IPv6 suffix? the suffix need to be a well known value among all nodes within the 4rd domain. this is appended to create a full IPv6 address that is used to reach the tunnel end point (either on the BR or the CE). this could very well have been a well known value, but since there was some discussion on what it should be, it can also be provisioned. e.g. it could be ::, ::1, or follow the dIVI format. cheers, Ole _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
