A frequently asked question here at Multapplied, both through Technical Support and Sales Engineering is: How do I improve voice over IP quality with Multapplied’s SDWAN solution?

First, let’s take a look at the common enemies of good voice quality and the practical real-world effects they have.

• Latency – delayed packets, resulting in slurred speech

• Jitter – spikes in latency causing clips and ticks

• Packet Loss – occasional loss off syllables or words

• Network Congestion causing garbled voice and call drops

Multapplied’s SDWAN solution can deal with all of the above, resulting in clear, reliable voice quality for your customers both on and off net.  Let’s review our recommended steps for success.

  1. Properly rate-shaped lines – This is imperative to a high-quality of experience.  When you try to send more data over an internet connection than it can handle, you increase the latency, and under extreme conditions you will begin to induce significant packet loss.  With Multapplied’s built-in leg testing utilities, you can determine where the maximum usable ceiling of the internet connections to your site are, and then rate shape those connections accordingly.
  2. Quality of service – Refers to the ability of a network to offer an enhanced level of service to certain types of traffic. For example, Voice-over-IP (VoIP) traffic requires lower latency and jitter than web and e-mail traffic. Multapplied’s SDWAN can be used to implement almost any type of traffic management strategy.

The following table shows the sensitivity of some common applications to network bandwidth, latency, and jitter.

 

Bandwidth

Latency

Jitter

DNS

Low

High

Low

VoIP

Medium

High

High

Video conferencing

High

High

High

Web browsing

High

Medium

Low

E-mail

Medium

Low

Low

Web TV/video

High

Low

Low

A network with ideal QoS would give each application the level of  service it required, even when more than one application is active on the network. For example, VoIP traffic would receive low-latency, low-jitter service while web browsing traffic receives high-bandwidth service.

Leg Bandwidth adaptation – For temporary events that normal QoS and rate-shaping cannot deal with on their own, such as a badly degraded line or lines, Multapplied’s SDWAN provides another feature to help mitigate these events and keep your users Quality of Experience high.   Bonded Internet is able to adjust leg download and upload speeds when it detects increases in leg latency or packet loss. This helps ensure that latency and loss remain as low as possible on a leg and maintains performance of both latency-sensitive and bulk applications.

Leg latency can increase for a number of reasons. Environments that bandwidth adaptation can handle include:

1.      Leg download or upload speeds have been set higher than the bandwidth  the ISP provides and the leg is approaching 100% load.

2.      Leg speeds have been set properly for normal use, but equipment failure or environmental issues have reduced the bandwidth available from the ISP.

Bandwidth adaptation can help in the above situations because reducing the sending speed reduces the latency and packet loss rate of the leg.

Some networks have issues that allow a leg to come online before going offline again after a very brief amount of time. This causes problems with the performance of a bond. Keeping a flapping leg out of the bond until it stays online can prevent many quality of service issues.  Flap detection and removal is also available with Multapplied’s SDWAN product.