Hi,
I understand that Tunnel Adapter LAN is for
encapsulating IPv6 packets with an IPv4 header
so that they can be sent across an IPv4 network.

Few queries popped up in my mind based on this :-

1.
Why is the numbering for the Tunnel adapter LAN
not sequential ? It is like 6,7,12,13,14,15,16.
A strange numbering scheme ?!
I tried to figure it out by thinking of some arithmetic
series. But, it does not seem to fit in. There is
a huge gap between 7 and 12. Any ideas ?

2.
What is the need for so many number of
Tunnel Adapter LAN connection ? Can you tell me a
scenario that requires all of those ?

3.
If i do 'ipconfig', Apart from ethernet adapter LAN
details, i get a series of statments as below -
Tunnel adapter Local Area Connection* 6
Tunnel adapter Local Area Connection* 7
Tunnel adapter Local Area Connection* 12
Tunnel adapter Local Area Connection* 13
Tunnel adapter Local Area Connection* 14
Tunnel adapter Local Area Connection* 15
Tunnel adapter Local Area Connection* 16

Except for the *16, all the other Tunnel Adapter
Local Area Connection's show Media Disconnected.

I did 'ipconfig /all' to get more information.

16,15,14,12 are Microsoft 6to4 Adapters
13,6 are isatap Adapter
7 is Teredo Tunneling Pseudo-interface

I understand that the above are for autmatic
tunneling so that the tunnel endpoints are determined
automatically by the routing infrastructure.

- 6to4 is recommended by RFC3056 for automatic
tunneling that uses protocol 41 for encapsulation.
It is typically used when an end-user wants to
connect to the IPv6 Internet using their existing
IPv4 connection.
- Teredo is an automatic tunneling technique that
uses UDP encapsulation across multiple NATs.
That is, It is to grant IPv6 connectivity to nodes
that are located behind IPv6-unaware NAT devices
- ISATAP treats the IPv4 network as a virtual IPv6
local link, with mappings from each IPv4 address
to a link-local IPv6 address. That is to transmit
IPv6 packets between dual-stack nodes on top
of an IPv4 network.
That is, to put in simple words, ISATAP is an
intra-site mechanism, while the 6to4 and Teredo
are for inter-site tunnelling mechanisms.

But, why Teredo is alone enabled by default in Vista ?

4.
If i do 'ipconfig /all', why only one Teredo is present
while four 6to4 are present ?

I searched internet for answers to the above queries
,but unable to find clear answers.

Any ideas ?

Thx in advans,
Karthik Balaguru