Re: [h323forum] Re: Codec negotiation question
Paul, Do you mean RFC 2508? In any case, Robert's point is indeed valid. This is where having a specialize GW that multiplexes the RTP streams for delivery over the long-haul is something practical. Perhaps we could take that up as a work item with SG16? It would be reasonable to specify how such an Gateway might function in order to trunk a large number of active calls over long distance. Anyone interested in such a work item? Paul ----- Original Message ----- From: "Paul Long" <plong@packetizer.com> To: <h323forum@mail.imtc.org> Sent: Monday, December 16, 2002 7:49 PM Subject: [h323forum] Re: Codec negotiation question
Robert,
Excellent point. I hadn't thought of that. I wonder what happened to cRTP. Anybody know? That would sure help.
Paul
On Mon, 16 Dec 2002 12:53:34 -0500 "Paul Long" <plong@packetizer.com> wrote:
I know lots of folks would like a means of expressing exact packetization, but isn't the solution trivial? All you need is a
FIFO and a few lines of code to re-packetize according to any internal requirements. Just write incoming frames regardless of size, e.g., 30fpp, to the FIFO, and read whatever size frames you want, e.g., 80fpp from the FIFO (only read if there are at least X fpp in the FIFO).
DSP hardware is not the only reason for wanting to have the remote endpoint send larger packets. We have many clients on long haul internet links (300ms+ ping times), often with a slow tail circuit (ISDN or even modem) and you REALLY want the other end to send more than one G.723.1 frame per packet to reduce the significant overhead that there is in
RTP.
It is unfortunate but true that there is no way of expressing a minimum acceptable number of frames per packet.
Regards, Chris
Davide,
There is nothing in the standard that requires the acceptance of an OLC or precludes terminating the call for any reason whatsoever so both EPs are technically compliant.
Packetization in TCS and OLC expresses the _maximum_ frames per
Paul Long wrote: packet,
but several vendors don't understand this simple concept and continue to produce products that expect an exact packetization. There is a good chance that that is why EP A is rejecting the OLC. It wants the channel opened at exactly 80fpp, although there is no way to express
small the this
in
H.323. IMO, if this is the reason, that product is broken.
Paul
Hi all,
I have a question about a codec negotiation. During H.245 negotiation, endpoint A (master) exports g711A-law with
packetization 80, endpoint B (slave) exports g711A-law with packetization 30. After that, endpoint A opens a channel with packetization = 20 ms. Endpoint B acknoledges the OLC and tries to open a channel with packetization = 30 ms.
Here Endpoint A rejects the OLC and the call is disengaged.
Does anybody can tell me which endpoint dosn't behave according to
the H323 standard?
Thank you in advance.
Davide
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