Hi,

The comments from Stewart where placed in the link
https://datatracker.ietf.org/doc/review-bashandy-rtgwg-segment-routing-uloop-00-rtgdir-early-bryant-2017-05-30/
instead of being sent to the maling list.

I have cut-and-pasted the review comments from the link above and put my reply inline. See "#Ahmed"

Ahmed



--------


This is the review for this draft and replaces the one I incorrectly
submitted a few days ago.

I have submitted a third party IPR disclosure relative to this draft,
there is clearly an overlap with the IPR disclosed against RFC5715,
and SR. There may of course now be other IPR.

#Ahmed
IPR disclosure will be made

Subject to resolving the above, we should adopt the draft since SR
can clearly be used to provide two stage loop-free convergence.

======

   This document provides a mechanism leveraging Segment Routing to
   ensure loop-freeness during the IGP reconvergence process following
   a link-state change event.

SB> Whilst technically that is a completely correct statement many readers
SB> will interpret that statement as the provision of link protection
SB> when you provide this service for link and node failure and
SB> presumable for metric change.

#Ahmed
I do not understand what is the concern here?

   We use Figure 1 to illustrate the mechanism.  In this scenario, all
   the IGP link metrics are 1, excepted R3-R4 whose metric is 100.  We
   consider the traffic from S to D.

SB> There needs to be a note of the symmetry properties of the links.

#Ahmed
Agreed
 =========

   Stage 2: After C elapses, R installs the normal post-convergence FIB
   entry for D, i.e. without any additional segments inserted that
   ensure the loop-free property.

SB> The timers can usefully be advertised rather than configured
SB> (draft-bryant-rtgwg-param-sync)

#Ahmed
We will change the text to indicate that "C" can be determined in a way that is 
out of scope of the draft
 ==========

5. Security Considerations

   The behavior described in this document is internal functionality
   to a router that result in the ability to explicitly steer traffic
   over the post convergence path after a remote topology change in a
   manner that guarantees loop freeness. As such no additional
   security risk is introduced by using the mechanisms proposed in
   this document.

SB> I don't think that there are zero increased risks. For example
SB> the extended convergence delay and the presence
SB> of routers without this feature magnifies the impact
SB> of a link flap attack

#Ahmed
Actually I think the comment is not accurate. The mechanisms proposed in this 
draft moves the traffic to the post convergence path faster, or worst case, at 
the same speed without using these mechanisms. So  if the proposed mechanisms 
do not enhance security, they are not adding any more risk


On 6/14/2017 1:56 AM, Jeff Tantsura wrote:
Guys,

Please work on resolving Early review RTGDIR comments.
https://datatracker.ietf.org/doc/review-bashandy-rtgwg-segment-routing-uloop-00-rtgdir-early-bryant-2017-05-30/

Thanks!

Cheers,
Jeff


On 6/13/17, 13:36, "IETF Secretariat" <[email protected]> wrote:


     Hello,

     This is a notification from the ID list for Routing Area Working Group.

     Document: draft-bashandy-rtgwg-segment-routing-uloop,
     
https://datatracker.ietf.org/doc/draft-bashandy-rtgwg-segment-routing-uloop/

     Change:
     Request for Early review by RTGDIR Completed: Not Ready. Reviewer: Stewart 
Bryant.

     Best regards,

             The Datatracker draft tracking service
             (for the IETF Secretariat)







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