Tag Archives: VoFi analysis

The Top Benefits of Voice over Wi-Fi (VoFi)

Much of today’s work is done on the move, meaning wireless networks are responsible for carrying much of the data that drives business. With voice over Internet protocol (VoIP) being the primary technology in use in the world of business telephony, the next logical step, voice over Wi-Fi (VoFi) is starting to make noise as well. VoFi offers a number of benefits for companies and their employees, more of whom are starting to take advantage of the technology. Here some of the biggest reasons to look deeper into the technology:

Cost Savings
For some business owners, opening the company’s monthly cell phone bill is pure terror. Making voice calls using Wi-Fi can actually eliminate the need to pay a mobile carrier bloated monthly fees and cut costs quite a bit. As long as there is a hotspot nearby you are good to go.

Far more than a mere buzzword, the amount and quality of work a company gets done is often the primary difference between success and failure. Increased mobile access gives workers the chance to make better use of what has traditionally been considered “downtime,” like traveling from one location to another. In other words, the flexibility of VoFi allows employees to make important calls from trains and planes across all terrains.

A major productivity driver, increased accessibility can boost customer relations by giving companies the ability to respond in a situation that needs immediate attention. For instance, VoFi can be a lifesaver when a decision-maker is out of the office but needs to be reached quickly to approve a service resolution. If customers are forced to wait for a problem to be resolved, frustration, decreased satisfaction and eventually customer churn can result.

For more information about WildPackets’ VoFi solutions, click here.

How to Get (and Keep) Control of Your Network Bandwidth

Garbled and choppy VoIP calls? Check. Slow Internet connection? Check. Loss of detail in video image? Check.

All these signs point to a case of bandwidth overload creating unacceptable network latency. With new protocols like 802.11n expanding the need for bandwidth with much faster data rates, it is more important than ever to have a thorough understanding of your network to prevent strain and overuse. Detailed below are ways to prevent latency issues associated with bandwidth overload.

Create a baseline.

An important first step in improving bandwidth management is to know the number of users and their bandwidth needs, as well as application bandwidth needs. This will determine the overall demand on the network and will help you allocate bandwidth appropriately. Networks have a rhythm, so be sure to assess these needs over a period of time, focusing on both daily and weekly rhythms. Once this baseline is established, you’ll have something to measure success against. Organizations can start this process by looking at their Internet connections, WAN links, WLAN environments, and data centers. A network analyzer is a great tool for creating baselines for both wired and wireless networks as it provides critical statistics in an easy-to-read PDF or web report. These analyzers allow organizations to identify problems in the network and validate performance and bandwidth utilization.

Pay attention to fluctuations in network resources.

New application introductions can tip the balance of bandwidth usage and have serious impacts on network performance. Visibility into network resource usage is essential to help network managers accurately meet user needs, particularly when bandwidth-intensive applications are in use.

Use dynamically-adjusting 802.11 WLANs.

802.11 WLANs have the ability to dynamically adjust to changing conditions and to configure themselves to make the greatest use of available bandwidth. These capabilities work best when the problems they address are kept within limits. To do this, you must understand the limits of the RF environment in the areas where wireless is to be deployed. Assess the overall area over space and time to get a quantifiable baseline of your environment.

Also, with the increased bandwidth of 802.11n, you’ll likely be considering applications like voice-over-wireless, which will require additional measurement techniques like wireless roaming to ensure proper operation of your network and ensure wireless quality. Be sure to plan wireless management upfront.

Prune your protocols/traffic.

Most networks have unnecessary traffic. Often, WLAN traffic has not been pruned and this can cause a clog in bandwidth. Check protocols that help manage the network like routing protocols, SNMP, etc. and determine if they have a purpose.

Constantly manage.

Networks and users are dynamic. They won’t always do the same thing twice and it is critical that organizations consistently and constantly review their network activity. It is important to see new trends approaching and make changes to your network to account for the behavioural changes in your organization’s user community.

VoFi Analysis: Get Started with our Guide to VoFi Monitoring, Analysis, and Troubleshooting

Online mobile VoIP (or VoFi) is coming. In-Stat anticipates 171.3 million users by 2013, with annual revenues projected at $10.8 billion (“Mobile VoIP – Transforming the Future of Wireless Voice; In-Stat In-Depth Analysis,” Frank Dickson, Sept. 2009). Previously on our blog we’ve talked about why VoFi and why now, specifically the benefits of VoFi. Now we’ll focus on VoFi monitoring, analysis, and troubleshooting.

Before you panic, take a deep breath. Analyzing VoFi traffic is basically the same as analyzing VoIP traffic. Remember though that wireless exacerbates factors such as jitter, latency, and packet loss that affect VoIP. Watch Using VoIP Metrics to Identify Network Problems for the specifics.

Begin at the Beginning: Your End User’s Call

When problems arise with VoIP or VoFi applications, you start in the same place. Your first step – before you begin to worry about statistics or packets – is to take the time to listen to representative calls. You want to hear what your end users are experiencing. Your ear will reveal telltale signs of latency, jitter, and packet loss. Be sure your VoIP analysis application supports playback of call audio, specifically the playback of individual RTP streams as well as the playback of the complete call. Without the audio, you can spend hours tracking down problems that aren’t due to either the application or the network – for example, clicking due to a damaged handset.

Take Your Network’s Pulse

Once you have listened to the call, you’ll want to take a look at what’s going on in your network.


Figure 1: Overview of Network Health

Immediately you see what you heard – the call quality was poor. The Mean Opinion Score graph gives an average over all calls occurring on your network. In this example there’s just one call, so you see the average for the duration of that call.

Dig Deeper

With Expert Events you’re able to verify what your ear told you.


Figure 2: Event Summary

With this call, you can see that there are a lot of physical errors: late packet arrival, retries, out of sequence packets, packet loss, excessive jitter, and more. With the cause identified, you can quickly begin to fix the problem. Looking at the call in its entirety, you’ll notice the call is closed, it had a successful ending – meaning the call wasn’t truncated – what CODEC was used, how long it was, and what the Mean Opinion Score was.


Figure 3: Call Statistics

In this example, the mean opinion score of 2.5 lets you know that the quality of the call was pretty poor. In the media view, you can drill down into each segment leg to determine why the quality was poor.


Figure 4: Call Details – R Factor, Mean Opinion Score, Packet Loss Percentage,
One Way Delay, Etc.

Understand the Differences between Wired VoIP and VoFi Calls

The next two figures show both a Wired VoIP call and a VoFi call packet-by-packet. (For an in-depth discussion of these calls, watch Anatomy of a VoFi Call: Packet-by-Packet.) You’ll notice that they’re pretty similar. The protocols used are different and with VoFi there’s the additional
step of authentication.


Figure 5: The Anatomy of a Wired VoIP Call

The differences involve: wireless segments instead of wired segments; signal interference; and wireless roaming.


Figure 6: The Anatomy of a Mobile VoIP (VoFi) Call

Learn More

Last week in Toronto, Joe Habib, Director of Global Services, presented “QoS of IP Telephony: Slaying the Three-Headed Beast of Jitter, Latency, and Packet Loss” at IT360. His presentation (PDF) is now available online. If you’re interested in ensuring QoS for your current (or future) VoFi deployment, you should definitely check it out.

In the presentation, you will learn:

  • What six factors contribute to poor voice quality
  • How to establish metrics for evaluating VoIP call quality
  • How to balance high-speed, bursty data requirements with
    requirements of high quality voice calls
  • How to capture data for VoFi Analysis and use VoIP metrics
    to identify developing problems
  • How to analyze a VoFi call packet-by-packet and verify voice
    quality with call playback