implementing VoIPTransitioning from TDM (Time Division Multiplexing or traditional phone service) to SIP (Session Initiation Protocol or Voice over IP) should be a consideration for any decent sized, multi location business.  SIP offers advantages like cost savings and scalability.  With SIP it’s possible for a company to maintain a single network, for all its voice and data transmission, instead of two separate networks. The transition can be complicated, however, and should be well planned.

Here are some items to be aware of before transitioning to SIP: 

Availability and interoperability:  SIP with local calling capability is not available from every carrier in every location.  Also, a carrier’s SIP service and edge devices need to be compatible with a company’s IP PBX (phone system) equipment.  It’s important to check a carrier’s equipment compatibility certification to determine if their service will be compatible with your company’s equipment.  This can best be accomplished during the Request for a Proposal (RFP) process, by providing each potential vendor with a list of locations and equipment to determine if there are any serviceability or compatibility issues.

Existing infrastructure: With SIP, voice communication rides over an organization’s data network.  If an organization isn’t currently transmitting voice over their data network, they’ll need to add bandwidth to manage the increase in traffic.  Otherwise, the company could experience dropped calls and network congestion.

Contractual issues:  Even if you would be receiving SIP service from your existing TDM provider, it’s important to understand what effect your existing contracts will have on your ability to transition to SIP.  You’ll want to determine if there will be penalties due to early termination or resulting from revenue shortfalls.

Pricing inconsistencies:  What calls are deemed local and the number of concurrent calls that can travel across the provider’s network are just two pricing components that could vary amongst carriers.  It’s important to use the RFP process to bring more visibility to each bidder’s pricing structure. 

911 Emergency Services:  TDM utilizes static circuits for voice communication.  The circuit is established and exists whether it is in use or not.  It’s much easier to establish the location of the calling party with TDM, facilitating emergency service dispatch.  SIP is not static, making adherence to 911 guidelines more of a challenge.  A SIP provider must maintain interoperability with the local exchange carrier (phone company), the Public Safety Answering Point, their customer’s E911 server and an E911 database.  E911 compliance cannot be taken lightly; it could literally be the difference between life and death.  E911 might not be as critical for a company operating out of a single structure, but it is hugely important for a company with multiple locations, including buildings with multiple floors and corporate campuses.

Call Security:  With TDM, there are fewer entry points for potential security breaches; a threat would need access to a company’s PBX or physical access to the telephone wire.  With SIP, there is much more exposure because it utilizes the internet.  Carriers should encrypt the voice stream and SIP protocol.  Companies considering SIP should determine if their infrastructure provides a secure foundation for SIP.

As you can see, there is much to be considered before transitioning from TDM to SIP.  It might be a good idea to solicit outside help from an experienced company, like CarrierBid.  If you would like to receive more information, please contact CarrierBid today or complete the form on the right side of this page.  

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