ISDN PRI & D-Channel

eng_ahmedas

Dear Friends
I wish you are fine ...... I am really confused regarding ISDN PRI and i wish you could help me understand it ......... When configring my T1 using pri-group, I am using CCS style signal (ISDN for example) .... I can configure multiplie pri groups with each pri group have some timeslots and each pri group can be owned by different customers ....... For example:

Customer 1 may have timeslots form 1 to 6
Customer 2 may have timeslots form 7 to 15
Customer 3 may have timeslots form 16 to 23

As we know, their is deticated D-channel for signal (channel 23) ...... My question, Does the three customers will share the same D-channel and their ISP will use the same D-Channel to send signaling information to all of them ???

Best Regards

azaghul

Having worked in TDM voice for too long, I've never seen a divided PRI.

Its more typical to see a partial PRI, on Australian E1's we regularly see PRI-10's, PRI-20's and PRI-30's (full PRI). I guess it would be possible to divide a PRI but I'm fairly sure the Telco would baulk at the idea.

shodown

What is your end goal for a customer to share a PRI? I've never done it, but i have spilt up call managers for multiple customers and some even buy there our Voice router to ensure they only get billed for there calls.

drkat

I have indeed seen shared PRI's ... Woah.. bringing me back here..

So the provider has built in their switch a TG pointing to say customer 1 who is using timeslots 1-6 but 6 is set as the D channel and then it's broken subsequently for the rest of the slots per customer. This allows the provider to bring in X PRI's off the same facility .. MOST of the time however unless they know for a fact customer A is not going to want additional channels they dont stack it like this, but I have seen this done at my previous employment

Another fun configurationis when they take a T1 and break it up 16 channels of PRI and 8 channels of data where channel 16 is your D channel

They do this by bringing in the channels from the tdm side and merging the channels in a dacs with the data then delivers it to the CSU who then breaks it up off to the PRI and ethernet connections. My last place loved doing this

Not to get off on a tangent here, but if you ever get a chance to work with T1 facilities and getting into the digital cross connects and what not, it's a BLAST...

eng_ahmedas

Dear Friends
Thanks for your explanations and special thanks for drkat