Subject: [Megaco] Usage of LocalControl,Local and Remote Descriptors !

From: "Simran Chadha" <[email-masked]>
Date: 30 Jan 2003 08:58:19 -0000

Hi List,

Can you please help me with clarifications in my understanding of sections 7.1.7 and 7.1.8 on the use of LocalControl,Local and Remote Descriptors.

As per draft-ietf-megaco-3015corr-03, in section 7.1.7,
If the value of a Reserve property is True, the MG SHALL reserve resources for all alternatives specified in the Local and/or Remote descriptors for which it currently has resources available. It SHALL respond with the alternatives for which it reserves resources. If it cannot not support any of the alternatives, it SHALL respond with a reply to the MGC that contains empty Local and/or Remote descriptors. 
The use of two negations - "cannot not" in the last statement will imply that - If it can support any of the alternatives, it SHALL respond with a reply to the MGC that contains empty Local and/or Remote descriptors.
I don't think this is what is meant to be conveyed here. 

Also in section 7.1.7 the first para starts - If the value of a Reserve property is True, .....
while the second para starts - If the value of a Reserve property is False, ....
Now as there are two Reserve properties - one Reserve Group and the other Reserve Value, One could be False and the other could be True. Then in this case what will be the inference - Should para 1 apply or para 2 ? Both the paras would seem to be mutually exclusive in what is needed to be done.

Also statements like "if it cannot support any of the alternatives ... " - will have two meanings.
1. Any -  Not even one - NONE of the alternatives is supported.
2. Any -  Atleast one   - While a few alternatives can be supported, a few might not be.

The protocol needs to be more clear on such aspects in the documents henceforth. The English language is understood in different parts of the world. Variations to agreed usage of the language terms will make it difficult for new users of Megaco protocol, like me.

Can someone please educate me on the exact usage and meaning of LocalControl,Local and Remote Descriptors ?

Thanks and awaiting comments and clarifications

Simran Chadha