Hi Ole, > -----Original Message----- > From: Ole Troan [mailto:[email protected]] On Behalf Of > Ole Troan > Sent: Monday, March 21, 2011 6:31 AM > To: Rémi Després > Cc: Xu Xiaohu; [email protected]; [email protected]; Templin, Fred L > Subject: Re: [Softwires] [dhcwg] fwd: > NewVersionNotificationfordraft-guo-softwire-6rd-ipv6-config-02 > > Remi, > > >> ... > >> any of the automatic tunnelling mechanisms could be used > as transport for "native addressed" IPv6 service (e.g. > ISATAP, 6to4, 6rd, ...). > > > > > > Since 6to4 addresses have a transition-specific format, I > don't think they can be considered as native. > > (OTOH, that is legitimately that 6rd addresses can be > called native because they cannot be distinguished from IPv6 > addresses that are routed by ISP's without any tunnel anywhere.) > > > > Since ISATAP only concerns IID's, an ISATAP address > > - is native address if the IID is prefixed by a native /64. > > - is a transition-specific address if it starts starts with > the 6to4 prefix 2002::/16. > > > > Do we agree on this more detailed analysis? > > I think we're talking about different things. > > what I think Fred was suggesting was that it should be > possible to delegate prefixes using DHCPv6 PD (and addresses > for that matter) over various types of tunnels. the > prefixes/addresses delegated/assigned would then be entirely > independent of the link-layer addressing (IPv4), and purely > use the automatic tunnelling mechanism for transport.
Right; in that case, the IPv4-embedded IPv6 addresses are used as next-hop addresses in forwarding table entries only, and rarely get used as source/destination addresses of packets sent over the wire. Returning to Xiaohu's question, there are several advantages to using non-IPv4-embedded native IPv6 prefixes: 1) native IPv6 prefixes that do not include an IPv4 embedded address can remain in service even if the CE's WAN interface IPv4 address changes. 2) no ISP-interior IPv4 addresses are exposed to the outside world. 3) there would be more stability in name-to-address resolution databases (e.g., the global DNS). 4) there would less incidence of site renumbering, since the CE could always request and receive the same (set of) native IPv6 prefixes. 5) multi-addressing is possible if the CE wants to request multiple IPv6 prefixes. > similar to BGP tunnelling. I don't really know anything about this. Does it do IPv6 prefix delegation and route optimization? Thanks - Fred [email protected] > cheers, > Ole _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
