E1 R2 long PDD

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Feb 10th, 2008
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I configured E1 R2 on AS5350(12.4T),when I tried to send the call to E1 from VoIP, the call can go through, but the PDD is too long. The caller got long silence befor ring back tone came. From the log, AS5350 got Seizure ACK then spent more than 10s to get the ring back from the Switch. Is there any way to reduce the delay? Thank you.


controller E1 3/2

framing NO-CRC4

ds0-group 0 timeslots 1-15,17-31 type r2-digital r2-compelled ani

cas-custom 0

dnis-complete


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Paolo Bevilacqua Mon, 02/11/2008 - 02:31
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Which country is this? You need at lease one contry set under cas-custom.

David Lin Mon, 02/11/2008 - 07:00
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The far end device is Ericsson Switch in Bangladesh based on ITU-T Q.421/Digital R2 signaling. So I use Cisco default setting, "ITU" in the country parametter and it doesn't show in the configuration.


In Backward Signals, Group A-3 is for "Address complete, change over to reception of B signals". I didn't see it in Cisco log(VoIP-->E1).


Feb 10 22:06:38.797: //4450/1CAC0D003B00/VTSP:(3/0:0):-1:0:0/vtsp_request_call:

Progress Indication=0, Info Trans Capability=0

Calling Number=14168402255, TON=International,

Called Number=88028801234, TON=International, Feb 10 22:06:38.805: from Trunk(3): [0x8872]:(0/29): Tx SEIZURE (ABCD=0001) Feb 10 22:06:39.017: from Trunk(3): [0x8872]:(0/29): Rx SEIZURE_ACK (ABCD=1101)


Feb 10 22:06:51.565: //4450/1CAC0D003B00/VTSP:(3/0:0):29:0:0/act_setup_pend_alert:

Progress Indication=8, Signal Indication=1 Feb 10 22:06:51.685: //4450/1CAC0D003B00/VTSP:(3/0:0):29:0:0/vtsp_dsm_peer_event_cb:

Event=E_DSM_CC_MODIFY_MEDIA_IND


Feb 10 22:07:12.873: from Trunk(3): [0x8872]:(0/29): Tx IDLE (ABCD=1001) Feb 10 22:07:13.085: from Trunk(3): [0x8872]:(0/29): Rx IDLE (ABCD=1001)


The far end Switch also got Seizure ACK(Bit=1011), but it got the Bit 1000 during the silence after Seizure ACK.


I also enable dnis-complete, but it doesn't help. What other parametters could reduce the delay? Thank you.


Paolo Bevilacqua Mon, 02/11/2008 - 11:35
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Hi, the reality is nobody uses the too generic "itu standard" and each country has his own customization. For bangladesh, I would try country india.


If that doesn't help we can look at the trace in detail.

David Lin Mon, 02/11/2008 - 13:56
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Thanks for your assistance.

Actually, I tried India as the Country but it got signal failure.


David Lin Mon, 02/11/2008 - 14:30
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From the call log, I found AS5350 spent a lot of time on sending the digits of destination number to the Switch. Which parameter could help it? I also tried signal end-to-end and dnis-complete but same result. I attached the trace for your reference. Thank you.




Attachment: 
Paolo Bevilacqua Tue, 02/12/2008 - 04:54
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Hi,

Most of time is spent sending the full ANI, are you supposed to send it in full ?


Also I'm trying to understand what is digit "16" sent in between digits and if it mandatory to do so.

David Lin Tue, 02/12/2008 - 07:39
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Exactly. I don't need to send the ANI in this case. But how to disable it on AS5350(I don't configure ANI for E1 as ds0-group 0 timeslots 1 type r2-digital r2-compelled ONLY)? or it has to be done on the Switch side?

I'm also confusing on the msg which is different to AS5300. If we can remove "digit 16" then it will save half time in sending digits.

And is there any way to shorten the interval of sending digits. It takes 300ms for every digits.

Thank you again.

Paolo Bevilacqua Tue, 02/12/2008 - 08:13
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Try removing ani in ds0-group command.

To shorten digit


voice-port 3/2:0

timing digit 100


Paolo Bevilacqua Tue, 02/12/2008 - 10:38
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Ok, did a bit of research.


I don't think you can shorten the digit send time, because you're using compelled, this means the switch will invite router with a backward signal "16" to send the next digit. If it was not-compelled or semi-compelled, probably it would be possible to shorten digit time.




David Lin Tue, 02/12/2008 - 11:27
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Bingo,I removed the ANI and now the delay is much better.

I will ask the Switch operator to set up non-compelled instead. I think I can't use it right now coz i got disconnect immediately(Cause Value=42). By Semi-Compelled,it's working but the delay is same as Compelled.


Thanks a lot.

Paolo Bevilacqua Tue, 02/12/2008 - 11:46
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You're welcome. I take R2 like an hobby because it's so obscure.


Out of curiosity, if you can talk to the switch guys, what do they say if you ask for PRI? Why are they still using something that has roots in the 30's ?


David Lin Tue, 02/12/2008 - 12:49
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Yes, I also asked them to provide PRI but they can't.

Honestly,I don't like R2 at all and don't want to spend too much time on it. But I still spent a lot of time.

Fortunately, I found out the reason with your assistance. Appreciate for that.

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