>> >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.. :)
The tunnel service is mentioned just as an idea and described simply in
Teredo.
Silkroad is a tunnel broken similar mechanism and it overcomes the
known limitations
of tunnel broker that it can not work if the user is
using private IPv4 addresses
behind a NAT
box.