Cisco CME with PBX integration
Hello all,
In this, document i will tell you how to successfully integrate Cisco Call manager Express (CME) with any third party PBX with examples. This process is called PRI Trunking or PRI integration.
Recently i was into PRI integration with 3 Cisco routers (Cisco 3945, 2951 and 4130) with IRIS lite PBX.
Integrating a PBX is not a that hard as we think, but it's bit sensitive. Sensitive in the sense while during the PRI integration we just need to be careful while assigning the parameters, they should match at both ends, i.e., on PBX side and CME side as well.
The very first thing to consider for PRI trunking is "cable". Yes, the cable which needs to connected between PBX and CME should be a cross over cable. For connecting a cross over cable, at cisco side we should connect to 1,2 4,5. In PBX side we need to check the cross connects and connect them accordingly. ( To be frank i am not sure on cable connectivity, but i am lucky to have good cabling guy with me during my implementation).
In this, document i will tell you how to successfully integrate Cisco Call manager Express (CME) with any third party PBX with examples. This process is called PRI Trunking or PRI integration.
Recently i was into PRI integration with 3 Cisco routers (Cisco 3945, 2951 and 4130) with IRIS lite PBX.
Integrating a PBX is not a that hard as we think, but it's bit sensitive. Sensitive in the sense while during the PRI integration we just need to be careful while assigning the parameters, they should match at both ends, i.e., on PBX side and CME side as well.
The very first thing to consider for PRI trunking is "cable". Yes, the cable which needs to connected between PBX and CME should be a cross over cable. For connecting a cross over cable, at cisco side we should connect to 1,2 4,5. In PBX side we need to check the cross connects and connect them accordingly. ( To be frank i am not sure on cable connectivity, but i am lucky to have good cabling guy with me during my implementation).
To check if the cable is connectivity is correct or not, we can verify it by the below command:
Router#debug isdn q921
//this command gives information on frames transmission between the pbx and cme.
Router#terminal monitor
//it gives you the console messages on your vty lines, if you are not getting any then give the command:
Router#conf t
Router(conf t)#logging monitor
Router#show isdn status
//this command gives us the information if the PRI trunk is established successfully or not.
//in this output we get layer - 1 and layer -2 information, which represents layer -1 means physical connectivity and layer - 2 is protocol based. (we will discuss layer 2 below)
If your physical connectivity is good, then you should see the "layer -1" "activated" if there are issues with you cable then it shows "Deactivated".
Take better help fro cabling, if you require. Because in my earlier deployment, i have troubleshooted for 8 hours and finally identified it as a cable issue. :( make sure it didn't happened with you.
After the layer - 1 is established, then go for layer -2 establishment, it will done only when the protocols on both ends match exactly.
Before going into configurations we need to understand 2 terms: network and user ( in cisco routers master and slave).
In PRI integration one device will act as network (provides the clock rate information to user device) and the other should be configured as user (Do not send clock rate information, expects to receive clock information from the other end). If the clock rate is not synchronized then the pri link will not be established, make sure to configure both ends respectively. I recommend to configure the PBX as network and cme as user, cause cme supports lot of features where few traditional pbxs won't support. By configuring pbx as network, then cme gets the related configuration as is.
layer - 2 parameters include:
isdn switch-type ?
framing ?
line-code ?
These are to be provided by the pbx guy, buy in my case the pbx guy is not aware of any and i found the switch-type by looking at his device configuration. I am from india and the device which i have seen, used switch-type qsig, other locations may use different.
Router#conf t //set the card type
Router(configure)#card type e1 0 1 //select the slot here accordingly, here my slot is 0 and 1 is port
Router(configure)#network-clock-participate wic 1
Router(configure)#network-clock-select 1 E1 0/1/1
Router(configure)#isdn switch-type <select accordingly>
Router(configure)#controller <?> <???>
if your card type is T1 then you need to use, ds0 group in the below configuration, if it's a E1 card then you need to use pri-group
Router(configure)#pri-group timeslots <1-31> //select the no. of channels
Router(configure)#voice-port 0/1/1 //select your module/slot/port accrodingly
Router(configure-voice-port)#bearer-cap speech
//This is important, without this command sometimes you may face issue with audio in calls.
Router(configure)#interface Serial0/1/1:15
Router(configure)# no ip address
Router(configure)# encapsulation hdlc
Router(configure)# isdn switch-type primary-qsig
Router(configure)# isdn incoming-voice voice
Router(configure)# no cdp enable
by this time, you should be able to get your PRI link UP. You can verify that by the below command:
Router# show isdn status
here, in the Layer - 2, it should show "Multiple_Frames_Established". Otherwise, try changing the switch-type, framing and line-codes.
That's it guys.. follow the blog for further configurations.
