FYI - SIP-H.323 interworking discussion for IETF BOF

Joon Maeng joon_maeng at VTEL.COM
Mon Mar 13 09:08:44 EST 2000

Comments inline:

"Johan Gerhardsson (ETX)" wrote:
> Hi folks,
> To clarify things:
> It seems that my writing was a bit sloppy when I wrote the problems about TTL and SEQUENCE OF... on the interop. I intended to describe two different problems:
> 1) GK cannot increase TTL in RCF.

This is true.

> 2) Mandatory parameters of type SEQUENCE OF ... can have empty list.

This is also true.

> 1)
> h323v2, 7.2.2:
> "The Gatekeeper may respond with an RCF containing the same timeToLive or a shorter timeToLive.".
> As I see it, according to this, a GK is not allowed to increase the timeToLive value proposed by the endpoint in RRQ, regardless if the endpoint makes a full registration or a keep-alive registration.
> I think it should be possible for the gk to do it.

I disagree.  As the endpoint is permitted to renew its registration any time up
to the assigned time to live, allowing the GK to increase time to live would
have no effect whatsoever (the endpoint would send keepalives at whatever
frequency it always wanted to).  There would be no effect, so there's no reason
to change.

As for your second point about SEQUENCE OF being permitted to have an empty
list, this has always been the case.  Is there a specific problem with this?
It looks more like a (true) observation than a problem to me!  I doubt you'll
get ASN.1 changed in existing stuff to make things SEQUENCE [1..something] OF
rather than SEQUENCE OF (even if such a structure is permitted - any ASN.1
experts wish to comment?).

Dr Chris Purvis -- Development Manager
ISDN Communications Ltd, The Stable Block, Ronans, Chavey Down Road
Winkfield Row, Berkshire.  RG42 6LY  ENGLAND
Phone: +44 1344 899 007
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