7 Digit Dialing in a centralized call-processing model

Hey TE,

I have a client that has a CUCMBE box at a colo with a single PRI. The CTO negotiated with the carrier and they do not get charged for long distance. They have 8 sites, and my question is - how can I configure 7 digit dialing with respect to each site's respective area code?

This seems like a common setup, and I'm kinda at a loss as to how I would go about handling it.

FWIW the gateway is a 2901 configured with MGCP.



  • tokhsstokhss Member Posts: 473
    A simple number translation will do the trick for you. Also, you need to find out how many digits are being sent by the carrier..

    for example... someone outside the office calls an employee @ 555 666 7712.... the carrier will truncate the number to 7712 when sending it to the office.

    so find out if the carrier is sending a full 11/10 digits number, or 4 digits.. its normal for 4 digits to be sent unless specified otherwise.

    also, are you trying to do 7 digit dialing outside the office, or interoffice dialing? as in.. site 1 calls site 2.. 7 digits sent between each site.

    edit.. just realized its a centralized dialing.. so you have 1 router with CUCM co-located somehwere and each office is simply routing into the colo via the net?
  • shodownshodown Member Posts: 2,271
    8 sites with a single PRI. Thats not a good design. that allows for 23 calls with 8 offices that has to be at least 8 people. How many people are at each office? if you don't mind me asking.

    Next what is the geo location of each of the sites are they all in the same area?

    If they are not in the same area you need to make sure the provider understands that you will be sending numbers out your trunk that don't belong to the area code. Some allow it, some don't. The good thing is that since the PRI is at 1 site everybody will be dialing into the same site anyway, but all the locations may have to share the same area code.

    For 7 digit outbound dialing you will just need to create a route pattern that points to the gateway, or the route list, route group method. MGCP will take care of the rest just ensure you drop the 9 on call manager.

    Depending on how many users are at each site we can give you an idea on how to dial between sites. More than likely you will be able to use 2 digits for site codes and 3-4 digits for internal extensions, or you can just assign a block of extensions to a site, but then you can't use the same numbers over again, so the site codes give you amazing flexibility.

    For inbound dialing has already been discussed.
    Currently Reading

    CUCM SRND 9x/10, UCCX SRND 10x, QOS SRND, SIP Trunking Guide, anything contact center related
  • tokhsstokhss Member Posts: 473
    Sho.. i think the design is acceptable with the amount of users they have, which is most likely going to be low. they prob chose this method due to budget and are running CIPC eliminating any voice resources at each site. Lets hope they have SRST configured in case the server crashes.

    but nevertheless, we need more info here. =)

    throw up a quick sketch with more info Agent.
  • shodownshodown Member Posts: 2,271
    It has to be low. 1 PRI for 8 locations I wouldn't maka design like that, and I have worked several installs where there is centralized dialing, but there is always more than 1 PRI.
    Currently Reading

    CUCM SRND 9x/10, UCCX SRND 10x, QOS SRND, SIP Trunking Guide, anything contact center related
  • tokhsstokhss Member Posts: 473
    Sho.. the way i see it, your right about 1 pri not being good .. but, if cost is really an issue and since we dont know the requirements, im gonna say its just not important apparently. ;)

    what i dont get is why have call manager at all with such a minimal setup... CME could handle all of this easy peazy!
  • Agent6376Agent6376 Member Posts: 201
    First, thanks to both of you for your initial responses.

    Tokhss: We're receiving 10 digits from the carrier. I agree that the client will probably tie up their 23 lines, but alas this is what we have. The client negotiated with the carrier to not have any long distance charges, so the fact that the PRI/CUCMBE are colocated in a different area code won't hurt in this scenario. All inter-office calls are routed through the network, which consists of a 50mbps L2MPLS circuit at the colo, with each site having a single MPLS circuit (ranging from 20Mbps to 30Mbps) on the same VRF. So essentially...there is no internet failover, nor is there SRST support at each site. I raised the big red flag for 911 dialing, and I was told that users can use their cell to make those calls in case of an emergency.

    Shodown: Most of the sites are in the same area code, and all but one are in the same state. Not all sites are being cut over at the same time, and right now I have a traditional 7-digit local dialing with an 11-digit long distance dialing route-pattern in place. As for inter-site dialing, do you suggest having site codes, or is it acceptable to just have say 21XX = Site 1 22XX = Site 2. The client does not have more than 50 users at any particular site. The one that's coming up next week, for instance, has 35.

    Where it breaks down for me is this: Lets say I configure 7 digit dialing for site 1-6 which are all 504 area codes.
    First, there's a route pattern for 9[2-9]XXXXXX Drop the 9, prefix 1504 (carrier wants the 1 because it's "long distance" from the PRI's perspective)
    Then I configure 11 digit long distance dialing 91[2-9]XX[2-9]XXXXXX Drop the 9, no prefix. Now, lets say that site 7 is 612 area code, and site 8 is 985. As it currently stands, as soon as someone dials their 7'th digit after the access number, the number is routed with a 337 area code. How can I configure CUCM to do the same thing for the 612 and 985 area codes? TIA!
  • tokhsstokhss Member Posts: 473
    Site codes arent needed in this case, unless you plan on using overlapping extensions or plan on using some sort of CDR billing system and filter based on site code.

    As far as allocating extensions.. based on whats been provided, it appears you have a max user count of 300 users between site 1 - 6 (lets say 50 max per location) ... an additional 50 for site 7 and 8 bring a total up to 400 users.

    Try not to think of how many you have today, but how many you may have in the future. Give a buffer in the amount of extensions applied per site.

    Its your choice from here.. you can create the following like, creating 3 partitions .. one for each area code. Since the majority of your users are located in 504.. then set the majority of your block to that partition.

    so 504_PT = extensions 5000-5500
    612_PT = extensions 6000-6100
    985_PT = extensions 7000-7100

    Now im curious to the pstn block that been provided to you. Are the numbers in sequence ? whats your NXX/Sub scheme? or are the all over the place. This will better determine how to setup your dial plan.

    Also, can you confirm if WAN access goes down, there is no local pstn access? is this why you said the users can call with their cell?
  • Agent6376Agent6376 Member Posts: 201
    The numbers are all over the place with the exception of one block of 29 contiguous numbers. In all, there are around 50 numbers.

    EDIT: That is correct concerning PSTN connectivity. Each site only has WAN connectivity, with no failover procedures currently being implemented. (NOT my idea, and I have voiced concerns about it.)
  • tokhsstokhss Member Posts: 473
    This is a good one.. all area codes are on the same pri right? so since everything is shared, something needs to be unique.

    So im retracting my initial statement about site access codes.

    Just off the top of my head, i say you can go with prefix or translation patterns with an access code.

    so.. user will dial 96.1234567 , translation pattern kicks in and routes 1 612 123 4567
    next, user dials 99.1234567, translation pattern kicks in and routes 1 985 123 4567
    next, user dials 95.1234567, translation pattern kicks in and routes 1 504 123 4567

    keep in mind, for intersite calling, no need for site access.. user will dial 3-4 digit extension.
Sign In or Register to comment.