Mike, the figure only partly solves the problem. The text that I referred to does not reflect what is in the figure, so this should be corrected. Furthermore, since the values that statusDeterminationNumber can take on are in the range 0..(2^24-1). The "modulo operation" with 2^24 has no effect whatsoever. It would seem that the real intent is that the _absolute_ value of the difference between the received statusDeterminationNumber and the locally generated statusDeterminationNumber determines which party is to become the master and which party is to becomes the slave. If the difference is smaller than 2^23 then the party that received the masterSlaveDetermination message becomes the master. Otherwise it becomes the slave. In the case that the two numbers are equal, the result is indeterminate. Regards, Frank ----------------------------------------------------- Frank Derks |Tel +31 35 6893238 | ServWare |Fax +31 35 6891030 | Philips Business Communications|P.O. Box 32 | |1200 JD Hilversum | |The Netherlands | ----------------------------------------------------| E-mail: mailto:frank.derks@philips.com | WWW: http://www.sopho.philips.com | ----------------------------------------------------- mike.nilsson@bt.com on 03-05-2001 16:04:45 To: Frank Derks/HVS/BE/PHILIPS@EMEA2 cc: Subject: RE: The use if statusDeterminationNumber in masterSlaveDeterminat ion Classification: Frank, The answer is in Figure C.4(v) of H.245. Best regards Mike Nilsson -------------------- Mike Nilsson Advanced Video Services

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-----Original Message----- From: Frank Derks [SMTP:frank.derks@PHILIPS.COM] Sent: Thursday, May 03, 2001 1:51 PM To: ITU-SG16@MAILBAG.INTEL.COM Subject: The use if statusDeterminationNumber in masterSlaveDetermination

C.2.1.4/H.245 states the following:

"If the terminal type numbers are the same, the statusDeterminationNumbers are compared using modulo arithmetic to determine which is master

If both terminals have equal terminalType field values and the difference between statusDetermination field values modulo 2^24 is 0 or 2^23, an indeterminate result is obtained"

The first sentence states that "modulo arithmetic" must be used to compare the numbers. I would say that that's a rather vague way of describing how the comparison must be done. Furthermore it does not tell me what the result must be for a terminal to be determined to be the master!

According to the second sentence, I know how to obtain an indeterminate result. So any result that is not any of the two specified values is not indeterminate, but I still do not know what the meaning of the result is. "Modulo arithmetic" is, however, introduced, but it is not clear whether this is the modulo arithmetic referred to in the first sentence. Furthermore, what is the significance of a result of 2^23?

I assume that the same rules that apply to the comparison of the terminalType field apply (i.e. the terminal with the higher value becomes the master), but this is not stated explicitly.

Regards,

Frank

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