I'm less familiar with Teredo, but there is a 6to4 scenario where an IPv4-based 6to4 host wants to access a native IPv6 host. In this scenario, the two hosts must communicate via a 6to4 "relay" that handles encapsulation/unencapsulation between 6to4 encapsulated IPv6 and native IPv6. Dependent upon on how "close" routing-wise the 6to4 relay is both hosts, it is possible for the routes taken between the two hosts to be very inoptimal and asymmetric.
If both end-points are IPv4 hosts with 6to4 encapsulated IPv6, then yes, the route taken can be as optimal as the IPv4 route. Bill Cerveny On Thu, 20 Aug 2009 12:34 +0200, "Pascal Hambourg" <[email protected]> wrote: > Hello, > > Ivan Shmakov a écrit : > > Do I understand it correctly, that the 6to4 and Teredo tunneling > > transition mechanisms work by establishing ``implicit'' tunnels, > > Yes, you can say that. > > > and, thus, are subject to the already existing IPv4 routing, > > The tunneling packets are. > > > while 6in4 routes the packets via the chosen IPv6 provider? > > 6in4 is just the encapsulation method (protocol 41) used by 6to4, and > one of the encapsulation methods used by some IPv6 tunnel brokers (which > are what you call "IPv6 providers" I guess). > > > Thus, it seems sensible for a single host to always implement > > Teredo or 6to4, even if as an addition to 6in4, in order to > > utilize the existing IPv4 routing. (Consider, e. g., two > > friends with hosts connected to the network of some IPv4 > > provider; the use of 6in4 implies that the traffic will be > > routed via yet another, possibly distant, IPv6, provider, while > > with either Teredo or 6to4, the packets will be routed directly > > via the IPv4 provider's network, resulting in lower latency, > > bandwidth consumption, etc.) > > IPv4 routing between two hosts may not be straightforward either. > > > May it therefore make sense for all the IPv6-compatible network > > software to support source IPv6 binding? > > Not more than for a classic multihomed IPv4 host, IMO. > > > -- > To UNSUBSCRIBE, email to [email protected] > with a subject of "unsubscribe". Trouble? Contact > [email protected] > -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
