Early Review of draft-decraene-rtgwg-backoff-algo-01
review-decraene-rtgwg-backoff-algo-01-rtgdir-early-shand-2015-05-13-00

  
  
    I have been assigned as Routing Directorate QA reviewer for this
    document. 




The following web page contains a briefing on
      the QA process.




​

https://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDirDocQa







The document is clear and concise and
      succinctly describes a proposed standardised SPF backoff
      algorithm.  This seems a useful step forward. The algorithm is not
      overly complex.







While suggested values for the various
      parameters are given, what is not clear to me is whether the
      intention is that these (or at least an agreed set) of these
      values are intended to be standardised as well as the algorithm.
      It would seem that different values might be suitable for
      different networks, but presumably the intention is that all the
      routers in a particular network SHOULD have the same values. Some
      discussion of this would be helpful.







I assume that "rib computation time" is the
      time that a RIB computation is to be (or was) STARTED? Obviously
      the FIB will not be updated for some time after this, in some
      cases for quite a long time after this! Does this delay need to be
      taken into account? I appreciate that in many cases it is
      difficult to ascertain reliably exactly when a FIB update has been
      completed. 







In reading the document I spotted the following
      nits.







Intro para 3







"some back-off algorithm have"







presumably algorithms








      and


      "to enforce that all routers


         triggers their SPF







presumably trigger













Bottom of page 3 


      "SPF_DELAY back to INITAL_WAIT. e.g. 5 seconds."







obviously should be INITIAL_WAIT








      4. Principle of SPG algorithm







3rd para







"and the while


         waiting for its stability,"







"and while waiting" would be better.








      6 Impact on micro-loops







"FIB are installed"







The FIB is installed







or







FIBs are installed




















      Mike