Leveraging your Wi-Fi network for use with VoIP

Network convergence is all about running both voice and data services over one single consolidated network.  For a wired network, that makes sense.  IP phones connected to an Ethernet network jack are now commonplace.  But what about your wireless, or Wi-Fi network?  Can that also become part of this converged network and be used for VoIP as well?

In this article, we’ll explore the ways in which corporate as well as shared Wi-Fi infrastructure can be leveraged to become part of your single, unified, converged network, seamlessly supplying you with high quality and secure VoIP services throughout your campus or business.

What VoIP needs

IP packet-based data networks weren’t initially designed to carry time-sensitive real-time services such as voice.  In order to accommodate this convergence, they have had to be modified, tweaked, and improved, to adequately transmit such services.  Mechanisms, including Quality of Service (QoS) as well as security protocols are employed to ensure both the level of quality as well as confidentiality of voice conversations.

For wired networks, this has indeed been achieved, and properly provisioned networks will provide high-quality and secure voice conversations with ease.  However, the wireless medium has some inherent characteristics that make both quality and security somewhat more challenging to attain.  These problems are by no means insurmountable, nevertheless, they must be addressed and mitigated.

Inherent problems of Wi-Fi for voice services

For many network professionals, one of the greatest obstacles to deploying voice over a Wi-Fi network is not the technical hurdles, but the administrative ones.

Wi-Fi has received a bad rap.  It’s true that compared to a wired network, it is more susceptible to security and quality issues, due to its very nature.  As a result, this has reached the ears of many managers and executives, giving the impression that Wi-Fi is unsuitable for voice services.  Well, this is simply untrue.  With the proper precautions, and with an appropriate network design, all of these issues can be alleviated, and such worries can be put to rest.

Among the characteristics that can potentially be problematic for the implementation of VoIP, the two most quoted and feared issues are described below:

Security – Signals from wireless devices as well as those from the access points that serve them are propagated in all directions through space and can thus be intercepted by any wireless transceiver within range.  Voice traffic over a wireless network is susceptible to the same vulnerabilities as those that all wireless traffic is exposed to.  Even so, the privacy expected for a telephone conversation is almost sacred and thus telephony is looked upon as something much more vulnerable than data, whose confidentiality must be protected at all costs.  Telephone conversations should remain private, period, and it is often this human psychological insistence that is the most difficult to overcome.

Quality – Data networks, including wireless networks, are not naturally suited to transmit real-time time-sensitive media such as voice and video.  The quality of the voice is subject to the timely and consistent transmission of voice packets.  Data networks are naturally “bursty” in the way they transmit data, but Wi-Fi networks induce an additional complication which involves the quality of the connection itself.  This depends upon the distance between the device and the closest access point, as well as upon the interference that may be present at any time.

What does VoIP over Wi-Fi look like?

When we talk about voice services over a wireless network, it typically involves a VoIP endpoint (a physical IP phone, softphone on a laptop, or an app on a smartphone) connected to a corporate Wi-Fi network, or to a Wi-Fi network administered by a third party (i.e. your business partners’ premises, a hotel, or coffee shop).  Some VoIP providers, such as Grasshopper actually incorporate a service called “Wifi Calling” which specifically leverages Wi-Fi networks for communication.  Now for connections on your own corporate network, you have control over how it is designed and functions, but when you’re connected to someone else’s Wi-Fi, you are obligated to use the network “as-is”.

So for voice over Wi-Fi, there are two approaches.  One that deals with optimizing your own corporate Wi-Fi network for optimal and secure voice performance and the other that deals with optimizing your endpoint to ensure security and quality regardless of which Wi-Fi network you are connected to.

Corporate Wi-Fi network optimization

If you have a Wi-Fi network within your company or campus, don’t use it only as a benefit for your guests.  Take advantage of it by optimizing its use with voice applications.  In order to tackle both real and perceived problems with wireless, consider the following best practices:

Wi-Fi Network security – Security for wireless networks is a robust and mature technological discipline.  Wireless networks are by their very nature, vulnerable to security threats that wired networks are immune to.  Even so, Wi-Fi security has developed to a point where correctly designed networks are considered as secure as their wired counterparts.  These same security principles should be applied to the fullest in order to ensure that IP telephony running over wireless networks enjoys the highest level of quality and confidentiality possible.

Network coverage – One of the reasons why voice quality may suffer is that the IP telephony device in use may physically be at the edge of the nearest wireless access point’s range.  When this happens, frequent retransmissions and packet errors occur, which in turn, increases jitter and packet loss which are two of VoIP’s worst enemies.  In such cases, the wireless connection may revert back to a slower Wi-Fi standard resulting in even more network congestion.  When designing the network, it is not unusual to overprovision coverage by increasing the number of access points.  Voice users are psychologically much more sensitive to intermittent connectivity than data users and limited overprovisioning for this purpose can be a solution for this.

Quality of Service – Whether deploying voice over any network, wireless or not, QoS mechanisms are a vital part of that deployment.  This is even more important when applied to a wireless network.  Network congestion, signal interference, frequency sharing with other users, and poor signal quality will all occur at one time or another on a Wi-Fi network, no matter how well designed it is.  This means that events such as packet delay, packet loss, or jitter can take place, all of which can be devastating to voice.  A properly provisioned and designed wireless network will eliminate these effects by utilizing the appropriate QoS mechanisms.  These should be configured on the wireless network and should also be normalized with those applied to the wired infrastructure to which it connects.

Enable roaming – Voice over Wi-Fi provides freedom of movement.  Nevertheless, this freedom requires that one access point will be able to hand off a wireless telephony user to another access point as the person moves from the coverage range of the first to the second.  This feature is called roaming, and not all access points support it.  If this type of movement is important to you, make sure that your Wi-Fi infrastructure supports it.

Optimizing your voice endpoint for use on third-party Wi-Fi networks

There are times where you will not be at your office, but on the road, at a customer’s site, or even at home and you’ll want to use your voice services on your mobile device.  Services such as GoToConnect and RingCentral, allow carrying your corporate number with you on your smartphone or laptop and connecting to a local Wi-Fi network is the ideal way to log on to these services.  In such cases, you are connecting to a Wi-Fi network that, for all you know, has absolutely no security or QoS configured at all!  Here are some pointers that will help you ensure both high quality and conversation confidentiality:

• Use a VPN: VPNs are services that encrypt the traffic of your mobile device in such a way so that even if your wireless transmissions are successfully intercepted, they will not be decipherable to the attacker.  This allows you to freely use your voice services over any Wi-Fi network, without regard for the security measures employed on the network itself.
• Get as strong a signal as possible: There is literally nothing you can do to improve the wireless infrastructure of a third party’s network.  The only attempt you can make is to physically position yourself so that you get the strongest signal possible (see your Wi-Fi signal strength bars on your device), making sure that you are not on the “edge” of the wireless network coverage area, thus ensuring you minimize transmission errors due to weak signals.

Conclusion

Wi-Fi networks are not something to be feared when it comes to using them for voice services.  They should be embraced, as they enhance the user’s experience by providing flexibility and freedom of movement.  By taking the appropriate precautions and performing the suitable best practices, using a wireless network for voice can become safe, secure, and highly productive for employees and executives alike.