The MPLS WG Archive

[Kireeti Kompella <kireeti@juniper.net>]

On Tue, 23 Apr 2002, Eric Rosen wrote:

> 1. The penultimate  node pops the last  label off the stack,  creates a data
>    link layer frame with IPv4 as the protocol type, and transmits the frame.
>    The receiver  of the  frame checks the  first nibble  to see what  the IP
>    version is  and treats  the packet as  IPv4 or  IPv6 depending on  the IP
>    version.
>
> 2. The penultimate node pops the stack,  checks the first nibble to see what
>    the IP version  is, and creates a data link layer  frame with either IPv4
>    or IPv6  as the protocol type, depending  on the value of  the IP version
>    field.
>
> What I meant was 1; I'm not sure which Kireeti meant.

I meant 2.  One could do 1, I suppose, but that pushes the hack to
the IP stack.  2 keeps the hack within the MPLS stack.

Kireeti.