In house VOIP systems

Posted on 2014-08-21
Last Modified: 2014-10-07
We are currently using a third party hosted VoIP solution and would like to move it in house. Our structure includes the necessary hardware to host a heavily virtualized network including exchange, IIS, SQL clusters and DFS. What I need to know is how to host our VoIP ourselves. I will need to know what equipment that is required, any software requirements and a basic explanation of how it ties together. (where do I get my dial tone from in order to utilize my equipment.)

We currently use Cisco asa5510 firewalls and have a high speed cable internet.
Question by:ICantSee
    LVL 7

    Expert Comment

    VOIP is voice over internet protocol May i know what is your purpose of VOIP? voip has no any major requirement on the equipment. It really depends on what you do with your VOIP and i believe the software and some equipment like pos system you can get from your vendor.  If your voip has anything to do with internet line then i think is better for you to set QoS.
    LVL 3

    Expert Comment

    Depends on what you would want to accomplish. Do you want an internal phone system only? Do you need it to send and receive calls from the outside (land lines)? If so, what type of lines are you going to use? E1 ISDN? IP trunk? that would define what type of telephone interface board or gateway you would need. Go to sangoma site to get a glimpse of the options. Then, as tankergoblis stated, it's just software.
    LVL 11

    Expert Comment

    by:Bryant Schaper
    You already are familiar with Cisco, if your needs are basic, I would recommend a cisco ISR router, 29xx series with CallManager Express on it.  You can connect IP phones to the it.  It will have all the basics.  There are other options like asterisk but Cisco will give you the best support, besides Shoretel and other phone vendors.  Be prepared to spend some coin, but may be cheaper than the hosted solutions over time, and you will have a address how you are bringing in the voice lines from the PSTN, PRI, ISDN, or SIP Trunk, or straight FXS ports with analog lines.

    Author Comment

    Thank you for the replies.

    Basically we need a phone system that gives us the ability to call anywhere we need to, receive calls from anyone who wants to call us, voice mail, etc.

    I understand and like the ISR router with Call Manager Express idea. What I don't understand is how I get the dial tone. The phone numbers need to be ported away from the third party that we are using now and end up somewhere that we can use them... right? If that means I have to pay a phone company like Verizon then what is the advantage of the CallManager Express?

    When we first looked into VoIP we looked at so called "in-house" solutions that were many thousands of dollars (10,000 +) and included a server and software. Do your replies mean that I do not need a dedicated server?

    We have 6 locations. We want the locations to be able to three digit dial each other. We also need the ability of the home office receptionist to handle the calls for all locations.
    LVL 3

    Assisted Solution

    The Dial tone in IP phones is simulated by the phones. There is no tone since you are using SIP for the transport of all the phone information from de CME inwards. With rules you can have each site handle its own traffic.

    Basically you have this:

    PSTN (public telephone network) ----copper wire----> Cisco ISR / ip pbx ----> VoIP (via tcp) in your network.

    so the dial tone ends in the CME of the cisco ISR or IP PBX. (you can even have an IP trunk from your telephone provider and save a lot of money in gateways). Then the calls are handled internaly over tcp (the call) and udp (the audio) so if you have an internal (reliable) network that connects all the sites, you'd be done with a cisco 1900/2900 with cme.
    LVL 11

    Accepted Solution

    You can get dial tone a few ways, ISDN, T1, Analog and SIP are the most common.  Real question is how many external calls do you want to be able to make/receive at the same time.  For example a PRI handles 24 calls.

    All of these would terminate to the router for Call Manager to use.  The reason you would use a provider and manage your own pbx is that it is cheaper right.  You can use a hosted solution but they will bill you monthly for the provider service and for renting their equipment, as such you will have monthly bills.  Certainly your due diligence is a cost analysis and ROI.

    Yes a new system will have a hardware cost too, router, phones and licensing.  You may not need a server depending the complexity of your setup.  Cisco offers call manager on the router in the firmware, and you can add a unity express card for voicemail.  But it depends how big you are.  For example, we run 250 phones and 17 locations and have our two call manager servers in a colocation facility.  We bring in two sip trunks from the local Telco and they provide 75 sessions on each so we can handle 150 external (either incoming from the pstn or outgoing to the pstn) calls.  The system was very expensive, servers and phones totaled about $350K.  But over the expected life of the system and the ability to handle our calls better we save a bundle.

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