Solutions for Optimizing Multi-Site Voice Networks
IndustryView | 2014

One challenge businesses face when implementing a Voice over Internet Protocol (VoIP) system is how to allot enough bandwidth for voice traffic. The task of managing traffic becomes even more complex when businesses have Internet connections at more than one location.

Based on the results of a recent Software Advice survey, this report will identify the networking technologies that multi-site businesses can use to effectively unify VoIP systems in an IP communications network.

Key Findings:

  1. Web-based apps suffer from more network issues (cited by 31 percent of respondents) than video (12 percent) and voice calls (11 percent).
  3. Only 9 percent of respondents say they “never” experience network problems; moreover, even fewer (1 percent) say they experience them “very often.”
  5. Twenty-one percent of respondents stream music at work, while 14 percent use workplace Internet connections to make personal voice and video calls.

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Unifying communications systems at multiple sites can save businesses money on operational costs and phone bills. However, multi-site networking can pose technical challenges. Because VoIP calls are transmitted as network packets on Internet connections that also carry many other kinds of data, they are subject to quality issues that don’t affect traditional voice services.

Internet connections supporting VoIP systems must therefore offer a consistent level of available bandwidth to ensure high-quality audio. To enable VoIP communications between multiple sites and establish a smoothly functioning phone system, businesses must understand each site’s unique bandwidth requirements.

With this in mind, we surveyed employees in business networks with multiple sites to identify the problems they face, and which bandwidth-intensive activities they engage in that threaten the performance of voice networks. Our survey focused on employees in organizations with at least two locations that communicate over the public Internet.

Users Have More Problems With Web-Based Apps Than VoIP Calls

One of the major goals of network optimization is improving the performance of business applications (such as VoIP software) for end users. Given this, we wanted to find out if employees in multi-site networks are satisfied with the performance of their communications solutions.

We asked respondents to identify which of their everyday, online work activities is most impacted by network issues. Surprisingly, few cite VoIP calls or videoconferencing, even though both modes of communication are relatively sensitive to minute changes in the performance of IP networks.

Thirty-one percent, however, identify the use of Web-based applications (i.e., software accessed as a service using a Web browser) as the activity most likely to be impeded by network problems.

Moreover, respondents seem to have just as much trouble with everyday Web browsing, wireless Internet and downloading large files as they do with VoIP calls or videoconferencing. These findings suggest that IP communications tools have been refined to the point where they work just as well as, if not better than, other Internet-enabled applications.

Online Activities Affected by Network Problems

Online Activities Affected by Network Problems

Jean-Francois Rey, product marketing manager at Alcatel-Lucent (a vendor of IP communications and networking solutions), explains that VoIP applications may function more smoothly than other Web-based applications thanks to a technology known as Quality of Service (QoS) engineering.

QoS refers to how data packets transmitted over IP networks are “tagged” to establish different priority classes for the transmission of different types of network traffic. QoS is enforced by VoIP hardware (e.g., a router).

QoS settings can be configured by administrators using the software interfaces for these devices. In some cases, however, network engineering may be necessary when businesses need to increase the overall level of bandwidth to adequately establish QoS. Network monitoring software on the sides of both the service provider and the customer can help to determine whether QoS mechanisms are operating effectively.

Generally, voice packets are assigned the highest priority class to ensure that voice applications continue to perform smoothly in sub-optimal network conditions. Web-based applications that are less sensitive to network problems are assigned a lower class of priority. Ironically, this can mean that Web-based applications function less smoothly than voice applications in certain network environments (as evidenced in the above chart).

Rey explains that, “In some organizations, the VoIP traffic engineering and application traffic engineering are not handled by the same teams.” This can lead to a disparity in performance.

In other network environments, Rey continues, business applications may have been assigned the same priority level as personal applications, instead of being prioritized through QoS. This can jeopardize the performance of business applications if enough employees are simultaneously using the network for personal activities. (We’ll touch more on this later in the report.)

Severe Problems Are Rare in Multi-Site Networks

Though telecommunications veterans live by the mantra that no network is problem-free, most respondents (89 percent) say that problems are relatively rare in their networks. One factor that may explain these findings seems to be the effective use of IT resources in respondents’ organizations.

  • Frequency of Multi-Site Network Problems

    Frequency of Multi-Site Network Problems
  • IT Staff in Organizations With Multi-Site Networks

    IT Staff in Organizations With Multi-Site Networks

We found that almost half of respondents work in organizations with an in-house IT team—paralleling the nearly half who “rarely” experience network problems. Digging further into this data, we compared respondents with and without full-time IT personnel to see how often each group experiences network issues.

  • Frequency of Multi-Site Network Problems: With Full-Time IT

    Full-Time IT Frequency of Multi-Site Network Problems
  • Frequency of Multi-Site Network Problems: Without Full-Time IT

    No Full-Time IT Frequency of Multi-Site Network Problems

The presence of full-time IT personnel clearly has an impact: 51 percent of those in organizations with full-time IT report that problems are rare in their networks, while this number drops to 38 percent for organizations without full-time IT.

Though it’s possible to successfully link systems without full-time IT personnel on staff, this data suggests that such employees can improve the performance of voice networks for organizations attempting to unify their phone systems across multiple sites.

Session Border Controllers Can Ensure Interoperability Between Systems

According to Mike Reinhart, senior product marketing manager at 8x8 (a provider of cloud-based unified communications and call center solutions), the effective use of IT for multi-site organizations requires more than just hiring full-time personnel.

Many businesses, he says, inherit “key systems and on-premise IP PBXs at multiple sites that may or may not be from the same vendor or generation. This creates a number of challenges for IT staff, as they have to figure out the different functions and capabilities of each site.”

Alcatel-Lucent’s Rey adds that this type of setup also creates headaches for end users. He recalls situations where companies “had legacy systems with old versions, and so their employees had different user experiences with phones and applications depending on where they were.” Thus, by centralizing communications systems, organizations can simplify life for both network teams and end users.

One way to achieve a centralized setup is to use a device known as a session border controller (SBC). This device stands between an organization’s local area network (LAN) and the public Internet in order to control VoIP traffic and other multimedia traffic based on the Session Initiation Protocol (SIP).

SBCs perform a number of functions, such as securing corporate networks by cloaking their structure from the public Internet. They can also ensure that equipment at different locations communicates effectively.

David Tipping, vice president and general manager of the SBC wing of Sonus (a vendor of SBCs and other networking solutions), explains that “an enterprise may have ‘Brand X’ IP PBXs in one location and ‘Brand Y’ in another. As a result, these networks speak in different ‘languages’ (i.e., protocols and codecs) and have trouble connecting.”

This situation can be resolved by the use of an SBC, which can “normalize, transcode and translate the various SIP variations,” Tipping explains. “This ensures calls are routed correctly, with the most efficient use of the network at the lowest cost.”

Many Employees Engage in Bandwidth-Hogging Activities at Work

Though QoS engineering and hosted solutions can fix many of the problems facing voice networks, employers still need to vigilantly manage their networks. This is because, according to our survey, many employees decrease the overall amount of available bandwidth through the various personal activities they engage in at work:

Most Common Bandwidth-Hogging Employee Activities

Most Common Bandwidth-Hogging Employee Activities

While personal Web surfing (reported by 46 percent of our sample) may be a waste of employee time, it’s not as much of a threat to voice traffic as activities involving streaming media.

Streaming demands much more bandwidth than Web browsing or downloading, since packets have to arrive in a timely fashion to ensure high-quality audio and video. Thus, the fact that 21 percent of employees are using their employers’ Internet connections to stream music at work testifies to the importance of QoS tagging.

Rey explains that some clients “like the QoS tagging for voice traffic, and ask to tag application traffic in the same way, perhaps to differentiate application traffic from music streaming, Facebook browsing etc.

By differentiating vital business application traffic from traffic generated by employees’ personal activities, organizations can avoid the problems with Web-based applications that were widely reported by our sample and improve the performance of their voice networks across sites.

Reinhart notes that the bandwidth needs of each physical site in a corporate network need to be individually evaluated, both because workers use bandwidth in different ways and because bandwidth constrictions frequently occur on the “last mile” of the organization’s connection to an Internet service provider (e.g., the leg of the network that actually reaches the business’s premises).


Respondents in our sample reported fewer problems with VoIP applications than with other Internet-enabled applications. This suggests that IP voice networking technology has improved dramatically since the early days of VoIP. In fact, users report more problems with normal Web-based applications than with applications for VoIP calling and videoconferencing.

Moreover, we see that organizations report a relatively low occurrence of perceptible networking issues overall—even those without full-time IT personnel to handle network engineering. This suggests that IP communications networks have improved to the point where many multi-site VoIP deployments are highly successful.

That said, some degree of network engineering is inevitable as organizations scale their phone systems to include multiple sites—especially if different sites are supported with hardware from different vendors.

Even though network issues are inevitable, their impact on vital business operations can be kept to a minimum using the practices and technologies in this report.


To find the data in this report, we conducted an online survey of seven questions, and gathered 228 responses from random employees in organizations with voice networks including multiple sites. All survey questionnaires undergo an internal peer review process to ensure clarity in wording.

Sources attributed and products referenced in this article may or may not represent partner vendors of Software Advice, but vendor status is never used as a basis for selection. Interview sources are chosen for their expertise on the subject matter, and software choices are selected based on popularity and relevance.

Expert commentary solely represents the views of the individual. Chart values are rounded to the nearest whole number.

If you have comments or would like to obtain access to any of the charts above, please contact

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