Re:Teredo vs Silkroad

>> >On Fri, 21 May 2004, Eiffel Wu wrote:
>> >> As compared with the Teredo, Silkroad has the following
>> >> strongpoints:
>> >>
>> >> 2. Silkroad can deploy without the support of relay, while the
>> >> Teredo needs the relay which advertises the reachability of Teredo
>> >> Prefix.
>> >
>> >That's not really true, I think. You can deploy Teredo using your
>> >own, arbitrary prefix, ("internal Teredo server"), and to the rest of
>> >the Internet, it looks like native IPv6 service.
>>
>> Cited from Teredo:
>> Teredo relays are IPv6 routers that advertise reachability of the
>> Teredo service IPv6 prefix through the IPv6 routing protocols.
>>
>> Teredo address format:
>>   +-------------+-------------+-------+------+-------------+
>>   | Prefix      | Server IPv4 | Flags | Port | Client IPv4 |
>>   +-------------+-------------+-------+------+-------------+
>>
>>    - Prefix: the 32 bit Teredo service prefix.
>>    - Server IPv4: the IPv4 address of a Teredo server.
>
>Yes, but look at the definitions:
>
>========
>2.5     Teredo IPv6 service prefix
>
>   An IPv6 addressing prefix which is used to construct the IPv6
>   address of Teredo clients.
>
>2.5.1   Global Teredo IPv6 service prefix
>
>   An IPv6 addressing prefix whose value is XXXX:XXXX:/32.
>   (TBD IANA; experiments use the value 3FFE:831F::/32, taken from a
>   range of experimental IPv6 prefixes assigned to Microsoft.)
>=========
>
>in other words, there can be multiple Teredo IPv6 service prefixes.
>Anyone can establish one just if the operator has a /32 prefix to
>spare. Many probably don't :).
How many ISPs have a /32 prefix ?
As i know, now there are no ISPs that have a /32 prefix in China.
Moreover, There are thousands of million NAT users in China, which will need
many of Teredo relays and corresponding Teredo /32 prefixes. When does Chinese
ISPs have so many /32 prefixes ? i don't think the day will come soon.

>> >> 3. Silkroad supports all types of NATs, while Teredo doesn't support
>> >> symmetric NATs.
>> >
>> >Obviously, this could be added very easily to Teredo as well, but it
>> >would require that Teredo servers would act as tunnel endpoints, and
>> >there would not be direct tunneling. That would burden the servers to
>> >that it would probably be undesirable.
>>
>> Whether or no, Teredo does not support symmetric NATs.
>
>See section 6. If you used Teredo just as a tunnel service, it would
>work with symmetric NATs as well. I don't think many people would
>want to deploy the servers like that though.. :)