VoIP Dial Peer Question

Unanswered Question
Oct 25th, 2007


I have the following topology

ext 200-->CME-A--WAN---CME-B---> ext 300

on CME A i have a VoIP DP to CME-B and vice versa. On CME-A I also have a POTS DP with the same pattern to CME-B what with higher preference for failed calls over IP.

What is happening is if i place the first call from ext 2xx to 3xx it goes over IP. If I hang up and dial the same number it routes over PSTN, and the next time I try it goes over IP....

If I take out the backup route over PSTN, I get a sucessfull call over IP, and the next call fails, and succeed again on the next call.....

What is going on?

running CME 4.2

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Paolo Bevilacqua Thu, 10/25/2007 - 09:05


your DPs have same preference hence taking calls round-robin. Configure preference as you prefer under dial-peer. Lower wins.

Hope this helps, please rate post if it does!

p.holley Thu, 10/25/2007 - 12:05

No that is not it. I should have mentioned i have that already setup. Voip DP is left with default preference and the POTS DP has preference 10.

Any more ideas

Paolo Bevilacqua Thu, 10/25/2007 - 12:12

Type "show dialplan number XXX" on the router doing that and check yourself. If the DP is matched by interdigit timeout, add "timout" after the number in above.

p.holley Thu, 10/25/2007 - 12:20

ok XXX here is the DP number? when you mention add timeout after the number above, what number are you refering to?

One more thing in regards to this issue, when i take out the pots DP, why is it that I can make a call on the 1st try, but not on the 2nd attampt, but can on the 3rd, so on and so forth on the VoIP DP.

Paolo Bevilacqua Thu, 10/25/2007 - 12:23

That would be "show dialplan number 300" if you have you haven't used T in destination-patter.

This will tell you in which order the DP are matched. If you repeat the command and they are ins some way same preference, you will see the order changing.

p.holley Thu, 10/25/2007 - 12:34

Just issued the command several times and the order of the preference remain the same, with VoIP DP preference 0 and the POTS DP preference 10 for the same destinatio-pattern.

Paolo Bevilacqua Thu, 10/25/2007 - 16:56

Ok, what is happening, is that the preferred DP fails one half of the times, so it re hunts to pots DP and succeeds. Another way to confirm that, try "huntstop" under preferred DP and calls should fail each other time.

Question is why it fails ? Check routing table for session target. Also check the terminating router "debug voip dialpeer". If you set "session protocol sipv2", the output of "debug ccsip message" is easy to read, unlike the h.323 debug.


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