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Tag Archives: Voice over Wi-Fi

Best Practices for Analyzing Voice over Wi-Fi (VoFi) with WildPackets

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    With 802.11n in full swing and 802.11ac rolling out next year, Voice over Wireless, or VoFi, is becoming more and more common in the workplace. Not only does this technology reduce cellular usage, but it also eliminates the issue of dropped calls at the office. Luckily for all of you, VoFi is also not a difficult technology to monitor and analyze with WildPackets.

    Scan Your Environment
    From a WildPackets perspective, VoFi data, like traditional VoIP, is just another data type on the network, so the first step in analyzing VoFi is no different than the first step in analyzing your overall Wi-Fi network – perform a scan of the 802.11 bands in use, 2.4GHz, 5GHz, or both. All that’s needed is a single, supported WLAN adapter for capturing traffic with OmniPeek, and you’re on your way. OmniPeek will scan through all of the channels you choose, dwelling on each channel for 500msec, or whatever dwell time you configure. A scan provides a great deal of information about not only your network, but the overall WLAN environment as well. The scan will identify all of your networks and APs (based on the location where the capture is performed), as well as all neighboring WLAN activity. Based on this information you may decide to do some channel reallocation to avoid conflicts with neighboring APs that are not under your control, or you may even decide to physically move some assets. The scan will also allow you to see the utilization of each of your APs, indicating potentially oversubscribed APs. Pay close attention to the wireless Expert events generated by OmniPeek, especially events like “Wireless RF Interference” and “Wireless Transmission Retries” which give you an overall indication of environmental issues that are affecting your WLAN performance, and which are likely to adversely affect VoFi performance.

    Zoom In On Your Network
    Now that you know exactly how your network fits in with your surroundings, it’s time to zoom in on your specific network. The best way to do this is to configure a supported WLAN adapter to capture traffic with OmniPeek on each channel in use by your WLAN, or at least each of the channels in use that can be seen from your current measurement point. This will give you complete, 100% coverage for all channels in use, making sure that you don’t miss any critical packets, and allowing for advanced inter-channel analysis like roaming. Identifying roaming events and measuring the overall roaming timing is critical for time-sensitive data like VoFi, as roaming latencies in excess of 150msec (not uncommon) will adversely affect VoFi call quality for any mobile VoFi user on your network.

    Zoom In On Your VoFi Calls
    As stated earlier, VoFi is just another data type on your network as far as OmniPeek is concerned, so if you’re capturing WLAN traffic you’re capturing VoFi traffic. There are several ways in OmniPeek to instantly isolate your VoFi traffic so you can get an immediate assessment. First, there’s the Voice and Video dashboard, which provides summary information regarding call quality, call volume (number of calls over time), and network utilization for VoFi versus all other data. A quick scan of the dashboard will let you know if you need more detailed analysis.  When you do, proceed to the Calls and Media views, which provide a detailed breakdown of each VoFi call. The Calls view provides detailed analysis regarding the signaling for each call, including a detailed, packet-by-packet bounce diagram so you can “see” the call setup in detail. The Media view breaks down each call into individual flows, since the packet path between the caller and the callee can differ from that between the callee and the caller. This view includes details of the quality of the actual voice transmission, including analysis of latency, packet loss, jitter, and MOS and R-Factor voice quality metrics. And if you’re really not sure how all of these metrics stack up regarding “real world” quality, you can play back either the entire call or just each leg of the call to hear what it really sounded like.

    Remember that VoFi is just another data type or application on your network, so analysis is similar to any other running app. Start by testing out your overall environment, the end user experience, and gradually dive deeper into your network to find the problem.

      The New TimeLine 2 Network Recorder is Well-Suited for Telepresence

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        Today, WildPackets announced TimeLine 2.0, the second installment of our premier network recorder and the fastest continuous network traffic capture and analysis solution to offer detailed network and VoIP statistics in real time.

        TimeLine sets a new standard in capture-to-disk speeds, offering unsurpassed network traffic collection and recording, quick data rewinding, simultaneous real-time network monitoring, and rapid search and forensic analysis of collected data. With TimeLine, network issues of any type can be identified, analyzed, reconstructed, and resolved quickly and efficiently.

        So, what’s new in TimeLine 2?
        With TimeLine 2’s ability to now display critical VoIP and network statistics in real time, including top nodes and protocols, call utilization versus network utilization, and call quality over time, it makes it easier than ever for network administrators to quickly pinpoint network issues. These capabilities are essential for businesses that are utilizing telepresence technologies and need to maintain network uptime.

        Additionally, network information recorded with TimeLine can be seamlessly analyzed with the latest edition of WildPackets award-winning OmniPeek Network Analyzer. OmniPeek gives network administrators complete visibility into the health of their networks in real-time.

        Advancements in the new version of OmniPeek include:

        • Compass, a new interactive dashboard that provides real-time visibility into key network statistics over long periods of time with on-the-fly data retrieval and complete OmniPeek analysis
        • Wireless 3-stream network analysis support for the latest 802.11n equipment
        • Call Data Records (CDR), which include key media quality and summary information
        • The ability to analyze over 2000 simultaneous calls to easily monitor

        If you’re at Interop Las Vegas this week, come visit us at booth #639 – we’ll be happy to give you a brief demo of what TimeLine can do for you. If you can’t stop by, check out our TimeLine OnDemand Webcast titled “The Need for Speed – No More Compromises!”

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

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            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.