This vendor-written tech primer has been edited by Network World to eliminate product promotion, but readers should note it will likely favor the submitter’s approach.
Voice over IP uses the session initiation protocol (SIP) to convert phone conversations to data and send it through a public or private IP network instead of using telephone lines or fixed bandwidth T1 and T3 options. This can be a brilliant way to cut costs, gain flexibility and more efficiently use existing resources, but consider these issues to ensure successful implementation:
* Native SIP. Ask your carrier if their network was designed to deliver SIP end-to-end and the size of their local telephone number footprint. SIP is an open standard protocol used to enable VoIP. Make sure your carrier isn’t patching together multiple networks, which may or may not use SIP and could cause quality degradation and make troubleshooting issues more difficult.
A native network is designed to carry SIP because it is made for IP traffic. Non-native solutions use older TDM-based networks, but connect them together with new equipment. Each time data passes through one of these older connection points, quality is impaired and causes jitter or dropped calls. Choosing a non-native SIP network could lead to extra work for the implementation team, a more complex solution for the engineering team to support, and potential installation scheduling delays.
You may also need to invest in additional equipment for a non-native SIP solution. Many enterprises operate with a mixture of older, non-IP premise PBXs and key systems, while other sites have upgraded to IP-capable gear. Having to lease or purchase gateway devices to allow the aging gear to speak SIP will add cost and support complexity, the opposite of what IT leaders are solving for. Some service providers have designed intelligent support at the edge of the network that eliminates the need for extra converter devices. Seek them out.
* Capacity is King. Taking the time to consider all future bandwidth needs will assure quality voice service after implementation. Evaluate – and account for – all network traffic, including voice data, video and other elements that will now travel over the corporate MPLS network.
Bandwidth is defined as the ability to transfer data (such as a VoIP telephone call) from one point to another in a fixed amount of time. It is measured in terms of speed, latency, delay and jitter. The good news is that in the SIP world, bandwidth can be purchased in much smaller increments than fixed ISDN, in the form of Current Call Paths (CCPs). Some SIP trunking solutions that replace outdated ISDN and TDM access circuits allow call paths to be shared across all enterprise office sites, eliminating waste and cost.
* Enhanced Features. Every good plan starts by thinking about the “what ifs.” When you decide to implement SIP-based voice, keep in mind business continuity and disaster recovery (BCDR) plans. SIP based voice services are more flexible and programmable, so make sure your provider has designed inherent BCDR options into their SIP services. These services may not be an up-front offering by your carrier, but they remain a critical element of any voice plan. Are they included in the service, or are there extra costs? Consider:
- E-911 – This service enables emergency services to know the location of employees in distress. If managed properly, fire and rescue should be able to find someone within minutes. There are static and non-geographic versions, the latter being preferred for mobile workforces.
- Non-geographic E-911 – In today’s workplace, business travel is an expectation. Non-geographic services automatically pass along updated location data to emergency responders to locate an employees in the correct location.
- Built-in Redundancy – A practical, programmable feature that reroutes calls to another location in the event of natural or man-made disasters — meaning no calls are dropped.
- Call Path Sharing – This feature allows streamlined voice operations by offering an umbrella of calling capacity (CCPs) shared across locations – and state lines. Instead of each building needing, for example, 1,000 phone lines, your company can determine how many phone calls need to be placed at one time and share that session capacity across the business.
- Phone Number Coverage – This feature provides the ability to have a phone number that matches your office location’s area code. Not all service providers have a deep database of phone numbers.
- Non-geographic Telephone Numbers – This feature provides virtual presence and the equivalent of national FX, so it reduces the need for some legacy feature charges.
- Native PRI handoffs – This SIP trunk feature delivers a native ISDN-PRI circuit to a legacy TDM PBX or other office voice gear without the need to install a gateway or Integrated Access Device, so these business sites can also benefit from SIP services without spending capital to buy an IP upgraded device.
- Enable Unified Communications applications – Converting your voice network to SIP enables it to support whichever UC service you select, hosted or on premise, so employees can benefit from IM presence, voice and video collaborative tools.
* Breaking Barriers. Your telephony and data engineers may not talk to each other yet but they will need to work together. Make introductions now. Your company needs to understand data networks to design a SIP network. Look for a provider with professional services to design it effectively and efficiently. The solution for your company will be unique because it needs to take into account the legacy equipment, various locations and future needs of your team. As the landscape continues to evolve, so will your telephony plan. There is a reason they call it a journey, not a destination.
* Alert Your Stakeholders. A key part of implementation is letting end users know what changes to expect. Employees will need to be briefed on the new service and what that means to them – new headset, processes and procedures for making calls, and a new way to receive voicemails. Make a list of the perks, like the ability to connect to their work phone remotely for days when it makes sense to work from home, receiving voicemails as an email with the message spelled out in text and access to products, like Micosoft’s Lync platform that make interoffice communications simple and straightforward.
Covering the items in this list will help make sure your company reaps the rewards of SIP implementation.
Level 3 is a global communications company with a full portfolio of voice solutions.
This story, "5 keys to successful SIP implementation " was originally published by Network World.