Re: RFC2460bis and draft-previdi-6man-segment-routing-header-08

[[e-mail]]

>>> How about something like this:
>>> 
>>>    Extension headers are only allowed to be added to packets at
>>>    the source node.
>>> 
>>> I think that was always the intent and this would be a clarification to the specification.
>> Bob,
>> "source node" might not be sufficiently specific in the case of tunneling, and "added" can be read as their insertion is somehow independent and we want it to be coupled with the insertion of an IPv6 header.
>> 
>> I think what we want to say is that extension headers can only be placed in packets by the same node that is placing the base IPv6 header in the packet. Hence they can not be added unless a preceeding IPv6 header is also added.
> 
> Good suggestion.

what about:

   1.  If the SRH specifies the complete path from source to
        destination, the router places the SRH directly in the datagram
        itself.

   2.  If the SRH only specifies a subset of the path from source to
       destination, the router uses IPv6-in-IPv6 tunneling [RFC2473] and
       places the SRH in the outer IPv6 header.  Use of tunneling
       ensures that the datagram is delivered unmodified and that ICMP
       errors return to the source of the SRH rather than the source of
       the original datagram.


which is verbatim from RFC6554.

cheers,
Ole