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VSX 500 H.245 odd Round Trip Delay messages

Occasional Visitor

VSX 500 H.245 odd Round Trip Delay messages



VSX 5000 (release disconnects after showing a odd RoudnTripDelay value:


08:46:12.490 D (NOCAT)        H323Conn[0]: RoundTripDelay -1ms


<0> 08:46:40.225 D (NOCAT)        H323Conn[0]: (AudioTx) Channel disconnected
<0> 08:46:40.225 D (NOCAT)        H323Conn[0]: (AudioTx) Channel idle
<0> 08:46:40.225 D (NOCAT)        RSVP: closing tx reservation 0 to
<0> 08:46:40.225 D COMM NOTF      commChannel state 20 closing -1 G.722.1C_48
<0> 08:46:40.226 D (NOCAT)        RTPTxChan[0]: closed
<0> 08:46:40.226 D (NOCAT)        RTPTxChan[0]: associated with NULL
<0> 08:46:40.226 D (NOCAT)        RTPRxChan[0]: associated with NULL
<0> 08:46:40.226 D COMM NOTF      commChannel state 20 closed -1 G.722.1C_48
<0> 08:46:40.226 I COMM H323 CONN audioTx (G.722.1C_48) state: close


IP is asigned to a RMX 2000 (release


What does the record  "Round Trip Dleay -1 ms" mean? That's impossible.


Will the VSX 5000 drop a call in case the H.245 Round Trip Delay T109 (according to ITU H.245 standar) expires two times?


It seems that the endpoints come to decide that de H.245 control channel is idle and then the endpoint disconnects.



Thanks in advance.

Message 1 of 4
Occasional Visitor

Re: VSX 500 H.245 odd Round Trip Delay messages

I have attached the log file from the begining to the end of the call.

Honored Contributor

Re: VSX 500 H.245 odd Round Trip Delay messages



This means that VSX received no answer to the RoundTripDelay querry. The call is dropped because this happens two times in a row - at 08:45:42.492 and 08:46:12.490.

“Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns- the ones we don't know we don't know.”
― Donald Rumsfeld
Message 3 of 4
Occasional Visitor

Re: VSX 500 H.245 odd Round Trip Delay messages

Thank you Mike, I agree with you.


Nonetheless, please, examine a new log file I've attached. This time, you can see more than two "RoundTripDelay -1ms" messages before the endpoint drops the call.


So, I'm not sure if "RoundTripDelay -1ms" is a message that notifies us that a H.245 Round Trip Delay Request hasn't been ansewred by a H. 245 Round Trip Delay Response. So that, although I also think what you told me, I am not completely sure. Perhaps, as the VSX5000 sends these message every 30 seconds, I must focus my attention on time records.


The H.245 standar says: "The sequenceNumber shall be the same as the sequenceNumber in the RoundTripDelayRequest for which this is the response [...] Only the RoundTripDelayResponse message which is in response to the most recent RoundTripDelayRequest message is accepted. Messages in response to earlier RoundTripDelayRequest messages are ignored. [...]"


I wonder if "Round Trip Delay -1ms" means that the RoundTripDelayResponse message doesn't match the Request message and the endpoint logs a "Round Trip Delay -1ms" record. The endpoint has received a missmatch message which, at least, is usefull to consider that the channel is not idle.


As you can see, two "Round Trip Delay -1ms" messages is not necessary followed by the enpoint dropping the call.


Please, examine the new log file and tell me what you think.


Thanks you for your help.