Subject: AP draft HPR spec

From: [email-masked] (Dave Finnie)
Date: Tue, 4 Oct 94 19:27:18 EST

All,

I have not yet completed my review of the HPR spec,
but here is what I have found so far:

(BTW, my PEDANTIC MODE is infuriatingly stuck on the
"ON" position :-))

* p6-3: 

  The calculation of the BIND PIU data length is incorrect.
  The assumption is the use of a FID2 (6 byte) TH yielding
  6 + 3 + 512 = 521. Since we are talking about NLPs here,
  FID5 should be used, yielding 12 + 3 + 512 = 527.

* p7-5:

  (Following on from Matthew's remarks.) The indication
  is that RS and CP NCE values may *never* change. Is this
  in fact never, or just for the life of a link ? If never,
  what is the proposed recovery algorithm if a node
  needs to be cold loaded. If for the life of the link
  (or other criterion) please indicate.

* p7-16:

  In the FSM, the description of state 4 should have
  the word "not" removed. Alternatively, the replace
  word "Partner" with "This".

* p7-21:

  I agree with Matthew's comments that a 30 min default
  value for the ALIVE timer is too high.

* 7-24:

  Segmentation and Reassembly. Forgive me if I have
  missed something here, but...How do you envisage
  RTP processing fitting into the node ? Specifically,
  would a new component exist that implements RTP
  functions ? That is my impression. If so, where does
  it fit in relation to PC and how does it interact ?
  Is PC a user of RTP ?

  What I am leading to here is: should PC segmentation
  + RTP segmentation be used together (i.e. RU 
  segmentation into FID5 PIUs + FID5 PIUs into NLPs). 
  There would seem little point. In addition, this
  could quite often produce poor performance, since
  RTP segments will often have smaller data segments
  than PC's knowledge of the link capabilities
  (since intermediate nodes in the RTP connection
  may have smaller link capabilities). Therefore
  each (large) PIU may be segmented into a reasonably
  large NLP + a small one.

  Could you please include a small paragrap or two
  describing the interaction, and if I am right, an
  indication that PC segmenting should be disabled
  over RTP connections ?

* p7-32: 

  Indicate "GREEN" is used if feeback is "RESTRAINT".

* p7-34: (near bottom of page)

  Rs = min(0.5 x Rs) is missing the second arg to
  min() function.

* pA-9:

  Discussion of a DATA field that is N bytes long, starting
  at sequence number x, should include sequence numbers
  x, x+1, ..., x+N-1 (not x+N). Similarly, the subsequent
  data field starts at sequence number x+N (not x+N+1).

* pA-29:

  The description of the length byte indicates that it
  includes the "reserved byte", but this byte appears no
  longer reserved (contains subarea route indicator).
  Also, bit 0 is the subarea route indicator, but so are
  bits 1-7. Is this just a typo and 1-7 supposed to be
  reserved ? If not, bits 1-7 need a different name and
  a description.

Having picked up on what you will notice are fairly trivial
points, congrats to all who contributed. It is a great
improvement over the original doco.

Dave