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This site was created as a place to share stories, tips, and troubleshooting help with ShoreTel/Mitel systems. ShoreTel/Mitel is obviously the MOST exciting VoiP platform on the market right now, and we realized there was no centralized place to discuss this platform, but now there is. Please feel free to join and share your experiences.

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  • BRI versus PRI

    I'm getting familiar with my new Shoretel system, and am wondering what the advantages/disadvantages of BRI versus PRI are.

    My understanding is that in terms of using VOIP is they don't play much part of the system.

    We currently have 7x BRI services (ISDN 2) with 2 lines each. To accommodate this, we have had 2x Shoretel BRI switches installed. We don't have any Shoretel PRI switch.

    To consolidate the 7x 2-line BRI services into one or two PRI services, then how would I go about doing this?

  • #2
    (7 BRI's-Unusual) So basically you have 14 channels vs 23 channels on a PRI; so if you went with a PRI all you would need is one. I would look at the cost of a PRI vs the cost of the BRI's. But I would think it would be would be cheaper and a lot cleaner to go with the PRI. You would be ordering a new circuit if you went with a PRI, so all you would need is a ST T1 box and port over any number you may want to keep from your BRI's.
    Config DNIS/DID if needed and point main number to call flow.


    • #3
      SEMI is quite correct in the conclusion that it is basically a cost benefit analysis and that a PRI will probably be the neater solution. With 7 BRI's you will need at least 2 90BRI switches which to me says that you should probably just by a ShoreGear E1 (not T1 as in USA). Also, PRI in Australia normally comes in 10, 20 or 30 channels.

      To achieve this consolidation you would sign up with a carrier who can provide direct connect service (i.e. not resell Telstra ISDN PRI) and then you would port your numbers from the BRI to the PRI (Telstra won't let you keep your numbers if you stay with them). Your ShoreTel reseller will most likely be able to help you with that. We've done it many times.


      • #4
        Thanks, mmm yeah I thought that the config was unusual. It seems that the growth capacity of the system is limited to a further 1x more BRI until the second switch reaches capacity.

        What is the capacity of a single PRI switch though? On a PRI switch, if I got:
        1x ISDN 5 (PRI) plus
        1x IDDN 10 (PRI)
        then how much capacity would be left in the single PRI switch for future growth?

        I also want to connect a GSM Gateway to the system and some of those need a PRI interface to connect to.

        By the way, I have got a price for a new E1 PRI switch of $5800 plus tax (Australian).


        • #5
          A ShorGear E1 can take upto 30 channels, but only from one source. That is you can't use 10 of them from Telstra and 5 from a GSM gatewate. ISDN E1 is a point to point deal in this case. Each ISDN coming into the system needs to connect to a dedicated ShoreGear E1 switch.

          Your observation about expansion is correct with the BRI scenario. There could be good reasons to go BRI such as timing. Telstra will install ISDN2 in 10 working days where PRI can take 30 working days...


          • #6
            Thanks Jason. I'm not a phone expert, but all is starting to become clear.

            With the current setup with 2x BRI 90's, is there any advantage in redundancy? (such as N+1) etc?


            • #7
              OK, I didn't realise you were already up and running. If one of your 90BRI devices goes down the trunks on the other one should carry the work outbound. Inbound is controlled by the carrier. If you change to an E1 now you may find that the 90BRI's become a bit extra, but the can each run quite a few phones, 4 analogue extensions and sip devices if required. The normal rules about N+1 apply in either case.

              I do have a client that went from BRI to PRI so we just turned the BRI ports into IP phone ports.