Subject: [Capwap] Review of resolution to issue 226

From: "David T. Perkins" <[email-masked]>
Date: Thu, 18 Jan 2007 15:57:25 -0800 (PST)

HI,

Below are comments for the resolution with date 2007-01-11
to issue 226:

1) The "Disc" state has a transition labeled "d" to "Sulking".
    This is a typo. It should be labeled "e".

2) There is a problem with transition "b" and notifications
    "n4", "n5, and "n6". The notifications should go to the
    "Disc" state, and transition "b" should be from the
    "Disc" state to the "Sulking" state.

3) The semantics for a WTP going through a list of ACs is not
    well specified. That is, does a WTP send Discovery requests to
    all ACs, and wait for responses to all ACs. Or does it send
    a Discovery request to the first AC in the list, wait for
    a response, and if none, then send to next. Likewise, if
    it tries to "join" to the first AC, and that fails, it seems
    like it should try to join with the next in the list. Also,
    when the WTP has no success joining with all the ACs in the
    list, it seems that the WTP should then send a broadcast
    Discovery Request.

4) It appears that there is a mismatch in semantics between
    DiscoveryCount and MaxDiscoveries.
    That is, DiscoveryCount is per AC, and MaxDiscoveries appears
    to be the total for all ACs.

5) The description for transition "Sulking to Idle (f)" specifies
    behavior for the AC. An AC is never in the Sulking state,
    and this should be removed.

6) The description for the "Join to Configure (g)" transition also
    describes the "Configure to Image Data (h)" transition. And the
    descriptions conflict. This is a messy description. (This will
    be addressed in the new state diagram proposal.)

7) The description for "Configure to Image Data (h)" says the
    WTP "determines that its version number is different". This
    needs to be fixed. (This will be addressed in the new state
    diagram proposal.)

8) The transitions "Configure to Reset (k)" and
    "Image Data to Reset (m)" are similar and the descriptions
    should be essentially identical. However, they are very different
    for both the WTP and AC. Also, don't see how notifications
    "n5" or "n6" could be valid, since they cause transitions from
    state "DTLS Setup" to the "Idle" state. But DTLS is in the
    "DTLS Run" state. Need help.

9) Not sure that the description for "Configure to Run (p)" is
    appropriate for the WTP. (This will be addressed in the new
    state diagram proposal.)

10) The "Run to Run (q)" needs to include downloading a new image
     to the WTP. (Note, I haven't verified the list of operations
     to make sure it is complete and correct.)

11) The letters for state transitions "r" and "s" are switched
     between the diagram and the descriptions. (That is, there is
     a simple typo.)

12) The "Run to Reset (r)" description says that either the WTP or
     AC may initiate, but the specific descriptions for the WTP and
     AC describe only the AC initiated behavior.

13) The "Run to Image Data (s)" should not occur (or possibly be
     only optional for low end WTPs, and a different op code be
     used than used for "image transfer operations" while still
     in the Run state.

14) To include "c1" in the state machine seems a little strange,
     since it is typically done only one time in the life time\
     of the WTP and AC, and as specified it is done for the WTP
     but not for the AC. (Thus, I'd remove it.) The same can be
     said for notification "n1".

15) The "c2" transition is shown coming from both the "Idle" and
     "Disc" states. It should be only in the "Disc" state.

16) The diagram shows the "c4" transition to the "DTLS Idle"
     state. It should be to the "DTLS Setup" state.

17) The description of "n3" says that FailedDTLSSessionCount is
     set to zero. Well, this variable is not used in the rest
     of the state machine, and it is confusing to mention it here.

18) The description of "n4" says that FailedDTLSSessionCount is
     set to zero. This doesn't seem correct. As specified, a
     WTP will continue to establish a session that the AC rejects.

19) the descriptions of "n6" and "n7 should include a reference
     to the good explanations found later in the text.

20) The first sentence of section 2.4.2 is not quite correct,
     since the meaning of "discovery" is changed from how it
     is used earlier.

21) The last paragraph of the message that has the sentence
     beginning with "DTLS decapsulation errors consist of ..."
     uses the terminology "authentication". This term means
     "message integrity checked" and "endpoint identity
     authenticated checked". Thus, it is a little confusing.
     I'd either replace "authenticated" with the appropriate
     phrase that included "integrity checked", or put both
     terms with the second one in parentheses.

Regards,
/david t. perkins

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From: "Pat Calhoun (pacalhou)" <[email-masked]>
Date: Tue, 23 Jan 2007 06:35:31 -0800

Dave, I just got to this e-mail after posting updated text for issue
226. I will take a look at the issues below, and determine whether they
are still relevant to the new state machine, and if so, will get them
fixed.

Thanks for the comments.

Pat Calhoun
CTO, Wireless Networking Business Unit
Cisco Systems

> -----Original Message-----
> From: David T. Perkins [mailto:[email-masked]] 
> Sent: Thursday, January 18, 2007 3:57 PM
> To: [email-masked]
> Subject: [Capwap] Review of resolution to issue 226
> 
> HI,
> 
> Below are comments for the resolution with date 2007-01-11 to 
> issue 226:
>