Silvano Rebai - Fotolia
The company introduced this week Versa SD-WAN technology that formulates a mean opinion score (MOS) for communication traffic and lets network engineers set policies that trigger specific actions if the score falls below a baseline. MOS is a number from one to five that indicates the voice or video quality at the destination end of the circuit. Satisfactory voice calls, for example, are typically in the 3.5 to 4.2 range.
Versa has developed algorithms that determine the MOS of each call based on metrics extrapolated from Real-Time Transport Protocol (RTP) and Real-Time Transport Control Protocol (RTCP) traffic flows. RTP combines its data transport with the RTCP. The latter lets monitoring applications detect packet loss and compensate for delays that lead to jitter.
Other factors used to reach a mean opinion score are the codecs used in a company's voice over IP and video conferencing application. In general, codecs compress digital data to move it faster over the network and then decompress it at the destination point. In doing its work, however, a codec causes some degradation in quality.
Network engineers can set policies that tell the Versa SD-WAN to take specific actions when the MOS is too low. Those steps could include changing the transport of the data flow, moving other traffic off the route to increase available bandwidth and cloning the communication traffic so it can be sent across multiple circuits.
Analysts split on value of MOS in Versa SD-WAN
Other SD-WAN vendors, such as VeloCloud, which was recently acquired by VMware, also provide mechanisms for monitoring and taking corrective actions to help maintain voice and video quality. In general, most products take into account common network problems, such as the loss of packets or delay in their delivery.
"The added support [within Versa ] for real-time voice and video will help ensure good-quality communications are maintained," said Mike Fratto, an analyst at Current Analysis, which is owned by London-based GlobalData.
Not all analysts, however, agreed that MOS scoring would improve voice and video calling.
"My guess is that this won't improve calling all that much, because SD-WAN solutions are already looking at things like jitter, latency, etc., for voice traffic," said Irwin Lazar, an analyst at Nemertes Research, based in Mokena, Ill. "They also can't deal with factors inside the LAN, such as poor Wi-Fi performance that can adversely impact call quality."
At its core, SD-WAN lets engineers steer traffic across multiple links, such as MPLS, Long Term Evolution and broadband. The connections they choose depends on the needs of the applications generating the traffic. Companies can select MPLS for data that needs a high-level of reliability, while using cheaper broadband for less sensitive data flows.
Vendors have added WAN optimization, firewalls, routing and quality-of-service features for communications as differentiators and to demand higher prices for their SD-WAN platforms.
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