Re: IPv6 over IPv4 using GRE tunelling

Dear Mr.Mat,
  My query is on protocol type field in GRE header. If you are aware, GRE
header has protocol type field which specifies what payload packet it has
encapsulated.
My question is what should be the value of protocol type field in GRE header
if GRE payload is an IPv6 packet. As per RFC 1701, the protocol type field
in GRE header will have value 0x8000 if the GRE payload is IPv4 packet.
  Expecting your reply.

 Radhakrishnan
----- Original Message -----
From: "Mat Ford" <[email protected]>
To: "S.Radhakrishnan" <[email protected]>
Cc: <[email protected]>
Sent: Tuesday, April 22, 2003 14:09
Subject: RE: (ngtrans) IPv6 over IPv4 using GRE tunelling


> The ethertype for IPv6 is 0x86DD. Your example is incorrect - the
ethertype
> for IPv4 is 0x0800.
>
> Mat
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of S.Radhakrishnan
> Sent: 22 April 2003 05:50
> To: [email protected]
> Subject: (ngtrans) IPv6 over IPv4 using GRE tunelling
>
>
> Hi,
>       I am presently working on IPv6 transition project. I am have
> doubt on IPv6-over-IPv4 using GRE tuneling  mechanism.
> The following is a block diagram for IP as delivery protocol for
> a GRE packet which as an IPv4 packet as payload.
>
>
|---------------------------------------------------------------------------
> ----------|
> |IPv4 Header   |  GRE header    |   IPv4 packet as Payload   |
> |Protocol field |   Protocol         |
> |
> |value = 47     |  type = 0x8000 |
|
>
|---------------------------------------------------------------------------
> ----------|
>
> I would like to know as what value the protocol type in GRE header
> should have to carry IPv6 packet as payload with IPv4 as the
> delivery protocol for the GRE packet?
>
>
|---------------------------------------------------------------------------
> ----------|
> |IPv4 Header   |  GRE header    |   IPv6 packet as Payload   |
> |Protocol field |   Protocol         |
> |
> |value = 47     |  type = XXXX     |
> |
>
|---------------------------------------------------------------------------
> ----------|
>
>
> I will be very grateful if someone can help me by answering my query.
>
> Thanking you
> Radhakrishnan
>