MeGaCo PropertyParm formatting question

Peter-Henry Mander erlang@REDACTED
Wed Aug 21 15:08:59 CEST 2002


Hi Hakan,

Thanks for that very pertinent remark about the local and remote 
descriptor, I may need to rethink how to acheive my aim.

Could it be that the ASN.1 really ought to have a 
LocalRemotePropertyParm to avoid ambiguity?

Pete.

Hakan Mattsson wrote:

>On Wed, 21 Aug 2002, Peter-Henry Mander wrote:
>
>pete> Hello everyone,
>pete> 
>pete> I've learnt and been using Erlang over the last couple of weeks to build 
>pete> a Gateway Emulator for testing purposes. So far it's been a successful 
>pete> project, with good results in staggeringly little time. 
>
>Great!
>
>Pete> So what do I need to do for each case of extraInfo?
>
>Nothing. In other contexts where extraInfo is allowed, you
>should use it exactly as you have done.
>
>You can however not use extraInfo in the context of local
>and remote descriptors. At least not when using the textual
>encoding. But I do not think that it should be used in the
>binary encoding either (even if it not is explicitly prohibited
>in the RFC).
>
>According to the RFC, the ABNF representation of local and remote
>descriptors are limited to be a plain octet string containing SDP
>info. This seems fair enough.
>
>Unfortunately the corresponding ASN.1 representation (in the RFC) is
>mapped to the more generic PropertyParm structure. This means that it
>it seems to be syntactically correct to use the extraInfo stuff when
>using ASN.1, while it is has no corresponding representation in ABNF.
>
>Even if our protocol stack allows the usage of extraInfo for the ASN.1 
>encoding, I suggest that you submit a question on the Megaco list before
>you use the extraInfo stuff in the context of local and remote descriptors.
>I doubt that it is allowed.
>
>/Håkan
>
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