Subject: draft-ietf-6man-segment-routing-header issue #61 not solved

From: "Adrian Farrel" <[email-masked]>
Date: Mon, 23 Apr 2018 23:07:04 +0100

You have proposed to fix this by writing...
 
   o  Tag: tag a packet as part of a class or group of packets, e.g.,
      packets sharing the same set of properties.  When tag is not used
      at source it SHOULD be set to zero on transmission.  When tag is
      not used during SRH Processing it MUST be ignored.  The allocation
      and use of tag is outside the scope of this document.
 
I don't think this is right. If there is some future use of the Tag field that requires a transit or egress SRH node to process the Tag field, but still interwork with a legacy source implementation then you need that that legacy source MUST set the Tag to a predictable value (presume you would want zero).  So you need s/SHOULD/MUST/
 
You might also...
OLD
      When tag is
      not used during SRH Processing it MUST be ignored.
NEW
    An implementation that does not support processing 
    the Tag field MUST ignore it and MUST forward it
    unmodified.
END
 
However, all this said, it still seems a little odd to define a field and not say what it is for. Why not just make it a reserved field? Then a future document can come and define it if/when there is a purpose.
 
Cheers,
Adrian
 
From: Darren Dukes (ddukes) [mailto:[email-masked]] 
Sent: 23 April 2018 21:48
To: [email-masked]
Cc: [email-masked]; [email-masked]; [email-masked]
Subject: Re: WG last call review of draft-ietf-6man-segment-routing-header
 
Hi Adrian.  Thanks for your review of rev11. 
 
The following issue numbers were open by you and are closed in revision revision 12. Please respond to this email acknowledging the closures so Bob can record it.
 <https://trac.ietf.org/trac/6man/ticket/57> #57,  <https://trac.ietf.org/trac/6man/ticket/58> #58,  <https://trac.ietf.org/trac/6man/ticket/59> #59,  <https://trac.ietf.org/trac/6man/ticket/60> #60,  <https://trac.ietf.org/trac/6man/ticket/61> #61,  <https://trac.ietf.org/trac/6man/ticket/63> #63, 
 
 <https://trac.ietf.org/trac/6man/ticket/62> #62 is not closed yet, sending me specific examples would be useful.
 
 <https://trac.ietf.org/trac/6man/ticket/64> #64 Still open.  It contains your minor issues/Nits.  19 of which are fixed/resolvable in rev12, 6 remain open.  I’ll send a separate email on this.
 
Thanks!
 Darren