Subject: [rohc] ROHC-FN initialising control fields

From: "Finking, Robert" <[email-masked]>
Date: Tue, 1 Aug 2006 14:17:17 +0100

One issue which has come up with ROHC-FN is the current lack of notation
for specifying the initial value of a field. In particular, for control
fields it is sometimes important to be able to specify an initial value
so that e.g. static encoding can be used for that field until some event
happens in that flow to give it a useful value.
 
The question is, how to notate the initial value of a field. The two
main alternatives are to specify the initial value inline, or in a
separate section. Example of inline syntax:
 
CONTROL {
  field == VALUE [ 16 ];
}
 
Example of separate section syntax:
 
CONTROL {
  field [ 16 ];
}
 
INITIAL_DEFAULT {
  field == VALUE [ 16 ];
}
 
The inline syntax is simple and neat, but has issues with how to notate
an initial value as well as specifying an encoding method to use for the
field (e.g. lsb), and may give the impression to the casual reader that
the field is always set to that value. The separate section is less
neat, but doesn't suffer from either of these problems, since it is in a
separate section though the reader may overlook it.
 
If anybody has a third alternative which has neither of the drawbacks of
the above two, suggestions are most welcome. Alternatively preferences
between the above two choices would be welcome also.
 
Thanks
 
Raffles
_______________________________________________
Rohc mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/rohc