The Aptela VoIP test measures the quality of your existing network connection in relationship to the Aptela network. The test analyzes four areas to determine if your network is VoIP-ready.

To run the Aptela VoIP Test, visit:

http://www.aptela.com/voiptest/

What do the VoIP Test results mean?

Firewall

The Firewall phase of the test checks the traffic flow between necessary ports from Aptela?s network to yours, and vice versa.

Any issues that arise through this portion of the test are easily resolved through configuration settings on your router or firewall.

Line Quality

In this phase of the test, three sub-tests are performed: Latency, Jitter, and Packet Loss.

Latency

Latency measures the amount of time a packet of data takes to travel from your network to Aptela?s and back. For VoIP to function properly, travel time must be under 100 ms / round trip. (For reference, Jitter should average less than 90 milliseconds from coast-to-coast.) High Latency numbers will result in echo or choppy calls.</p>

Jitter

Jitter is the measurement of variation within the Latency testing. For example, if one packet of data arrives with a Latency measure of 10 ms and the next arrives with a measure of 50 ms, the Jitter measures 40 milliseconds. In general, some Jitter is always present; however, it should rarely measure above 10 ms.

High Jitter can result in the phone dropping packets. IP phones only buffer a handful of packets, and they may drop if lag time is too high. Each packet is a tiny portion of the call so if this happens too often, the call becomes choppy.

Packet Loss

Packet Loss occurs when data is lost in transmission between your location and Aptela. Packet Loss causes choppy calls.  This value should 0% normally.  Results 2% and above will result in noticeable call quality issues.

Packet Loss and Jitter both are caused by congested networks or under-performing equipment. Congestion can be hard to track down as it can be either at your network level, your ISP, or in the wider Internet traffic. For example, a fiber cut on one major provider can impact other providers as traffic is re-routed to new routes. Congestion can also happen from hard-to-pin-down causes like daily Microsoft Windows updates or employees streaming radio or video to their computers.

It is important to note that each component of line quality (Latency, Jitter, and Packet Loss) can have different effects when unsatisfactory levels of one are present with another. e.g. Latency combined with high Jitter and Packet Loss indicates a congested network or under-performing equipment. Latency with no Packet Loss and low Jitter is generally more of a result of distance or a very poor configured route table by your ISP.

A Note on Routers and Firewalls

When in use, VoIP passes a continuous stream of traffic over your network. Some routers and firewalls are not designed to efficiently handle the constant traffic. Additionally, if you are using VPN or Firewall features of the router, this can introduce more load on the equipment. Therefore, it is advisable that you have the proper equipment for your needs. If you have any questions on optimal equipment or network / router configuration, please talk with your Aptela representative or IT professional.

SIP Initialization

This phase of the test attempts to create a SIP handshake between your location and the Aptela server. This test is similar to the Firewall test, but it checks to see how your firewall impacts the handshake. Success in this part of the test is positive, however any failures do not necessarily mean that you cannot place calls. It most likely suggests that the firewall or router is masking some of the info. A common example is a firewall that has SIP transformations turned on or many Cisco routers that perform header re-writing.

Speedtest

The Speedtest analyzes the upload and download speeds between your network and Aptela?s. The actual speeds may differ from the rated connection of your line due to traffic passing through several network providers along the way. Speeds can also be affected by existing traffic on your network.

From the speedtest you can estimate the number of simultaneous calls that can be handled by your network. The methodology is to take the smaller of the two numbers (likely the upload) and divide by 100. The resulting number is the number of concurrent calls you effectively handle without impact to call quality.

Summary

If you have questions on any part of this test, please talk with your Aptela representative. As long as sufficient bandwidth exists, most issues can be resolved with some minor configuration adjustments.

Quality of Service (QoS) is always recommended in VoIP environments. Please consult with your IT professional on setting up a Quality of Service (QoS) enabled network. Aptela can provide support and documentation, but QoS is best handled by a professional familiar with the local network and requirements.

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