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"PRI Idle" timeslots always open with G729 configuration between 2 Meridian PBXs

Is it possible to configure support for the below described requriments with Cisco routers/devices?

Topology:

2 x Meridian SL-1 PBXes with a Cisco network between them to support the following requirements:

-QSIG CCS signaling, Euro ISDN, PRI net5

-The signaling channel (D-channel) is transparent (P2P)

-All B-channels (30) should be open towards the pbx’s in both ends

-No traffic to be sent over the wan  unless there is any calls going (spoofing)

-The pbx chooses which B-channel to use for a call, signals it, and the Cisco routers must then "unspoof" this channel

-Codec to be used G729

A collegue was suggesting this way to solve it:

-Configure all the channels on the PRI on the routers/gateways connected via PRI to the to be open permanently

-Congure timeslot 16 to 64kbps transparent

-Configure the othe timeslots to G729 and Voice Activity Detection to make sure no data will be transmitted unless there is any speach going over

Anyone configured anything simliar before?

I guess a challenge would be to have the timeslots open with g729 configured?

Best Regards

Ørnulf

7 REPLIES 7
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Hall of Fame Master

That is a normal configuratio with Cisco routers. You should engage a reputable consultant to put it in practice.

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Thats not an option and not much help. Its certanly not a very common configuration and TAC even could not give us any help on this.

I belive it is transparent CSS as described in this document I might need:

http://www.cisco.com/en/US/tech/tk652/tk653/technologies_tech_note09186a00800a96c1.shtml

With this post I was hoping for some feedback from other people that had done the same configuration incorporating Meridan PBXes and Cisco routers between like described above.

Best regards

Ørnulf

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In any case, you probably do not need transparect CCS. It is only needed for non ISDN signaling, but you have ISDN. Just confgiure switch-type QSIG, and router will realy any message to the other side.

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Paolo,

do you think that simply configuring switch-type QSIG would helps us achive the following requirements:

  • Have all the channels beeing up and connected permanetly.
  • Have the timeslot 16 set to 64kbps transparency
  • Have the other timeslots set to G729 og Voice Activity Detection.  (Target: to have no data going across unless there is a call going across(voice) )

Our customer calls this feature PRI-IDLE on their Meridians.

BR

Ornulf

PS: some links I am looking at to see if this is what we can use for configuration:

http://www.cisco.com/en/US/docs/ios/12_0/12_0x/feature/guide/tccs_7xk.html

http://www.cisco.com/en/US/tech/tk652/tk653/technologies_tech_note09186a00800a96c1.shtml

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Why you need the channels constanly open, as mentioned above,, if the PBX uses ISDN/Q.SIG, you don't need that.

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Paolo,

thanx for your reply. Its not crystal clear, but our customer tells us its because they have a propritary CDR application that actually do billing on voice activation detection on the permanent open channels.

I know, a very odd case, but thats the requirments we are met with.

So again in short, we need to configure:

"PRI Idle": Permanently open timeslots open with G729 configuration on the PRI between Meridian PBXs and Cisco router:

Topology: Meridian PBX-PRI-Cisco router-WAN-Cisco router-PRI-Meridian PBX

  • Have all the channels beeing up and connected permanetly.
  • Have the timeslot 16 set to 64kbps transparency
  • Have the other timeslots set to G729 og Voice Activity Detection. (Target: to have no data going across unless there is a call going across(voice) )

All inputs/suggestions to how to configure this on the Cisco routers are greatly appreciated.

BR

Ornulf

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Yes very strange, so there is another peice of hardware that do billing based on voice dectection? Can you identify it, personally. Note however that assuming such a thing, it would work on regular PRI as well, when detecting the transition from idle B channel, to open-idle, to to open-voice.

That is because many customers often don't know exactly how things are done. They wouldn't be customer otherwise.