While a growing percentage of enterprises worldwide are transitioning their voice and telephony systems to more agile and flexible unified communications (UC) solutions, inconsistent quality and reliability challenges still prevent them from realizing the full potential of their UC investments. In many cases, the UC systems themselves are working perfectly fine – it’s the underlying network that causes intermittent issues and frustrations for end users.
Information from UC systems that support quality of experience (QoE) monitoring suggests that 60 to 80 percent of QoE problems are actually caused by issues with the underlying network. Such large numbers are particularly frustrating for application IT administrators, who have only minimal visibility into or control over the networks their systems must rely on. To address network-related QoE problems, the International Multimedia Telecommunications Consortium (IMTC) created a use case specification for automating UC QoE using software defined-networking (SDN).
IMTC also worked closely with the Open Networking Foundation (ONF) liaison to develop the use cases, as well as a standardized northbound interface (NBI) specification. Through an IMTC use case specification, video, and ONF technical NBI specification, IMTC presents the use case for what it calls Automated QoE Service using UC SDN. One of the key use cases of UC SDN is dynamically configuring the QoS of the network infrastructure to ensure a high QoE based on requested unified communications and collaboration (UC&C) traffic load requirements. The use case focuses on end user, real-time media application that communicate their bandwidth and traffic treatment to auto-program dynamic QoS policies across the network on a per session basis.
With VoIP based telephony, network operators traditionally have achieved high QoE by deploying a separate voice VLAN network that is exclusively designed for VoIP and isolated from bursty data traffic. Because UC&C systems deliver everything from video and instant messaging to web conferencing using the same converged IP network from a single converged endpoint, traditional approaches for managing QoS are inadequate in the modern world.
The IMTC use case specification explains how in a UC&C environment, QoS mechanisms such as QoS marking, admission control, and traffic engineering suffer from a number of shortcomings that make UC&C difficult to operate for large-scale deployments. For example, since UC&C endpoints mix latency sensitive voice and video traffic with non-real-time data traffic on the same device and network connection, it’s no longer possible to apply QoS markings to media traffic based on the device or VLAN from which the traffic originates, the de facto standard for IP phones.
The use case for automated QoE service relies on SDN controllers to access and control network elements and expose automated QoS APIs. Or as IMTC UC SDN Activity Group Co-Chair Chris Lauwers sums up simply in this video, “The opportunity with SDN is the ability to use abstractions to find out information about the network and tell the network to do something about it.” UC SDN allows UC&C applications to dynamically negotiate application treatment with the network and ensure any QoS configurations automatically match application requirements, which can change mid-session as users switch between modalities.
The use case explains how SDN essentially closes the loop between UC apps and the underlying network. The use case architecture conceptually proposes a new module called the “quality of experience module” to be part of the SDN infrastructure, either running in the network controller or somewhere with it. The automated QoE service module includes four submodules:
- Dynamic QoS Marking: applies the appropriate QoS markings to media flows associated with UC&C sessions and requests proper QoS treatment for that traffic
- Admission Control: decides the class of service (CoS) and bandwidth to be allocated in response to the application resource request
- Dynamic Traffic Engineering: governs the allocation of total available link capacity to different classes of service, as well as path selection based on available link capacity and requirements of the corresponding applications
- Policy: allows administrators to specify the desired policies and behaviors for the QoS marking, admission control, and traffic engineering modules.
While this standardized NBI specifications is new, there are various vendors such as Aruba Networks, Microsoft, HP, Extreme Networks, Meru, NEC, and Nectar that have been shipping UC SDN enabled products for some time. The benefit of having an open standard NBI is that it will help drive multi-vendor interoperability and broader adoption of UC SDN and NBIs across the industry.
By providing network QoS automation, UC SDN provides tremendous agility while improving UC performance, so that applications can actually start taking advantage of the network infrastructure rather than be hampered by it. To learn more, check out the following resources or get in touch with your UC and networking providers to better understand how they are supporting standards-based initiatives in the IMTC and ONF:
- IMTC UC SDN specification: “Automating Unified Communications Quality of Experience Using SDN”
- ONF NBI specification: “Real-Time Media NBI Rest Specification”
- IMTC video featuring Chris Lauwers, IMTC UC SDN activity group co-chair
- ONF Technical specifications ONF Technical specifications
- Get involved with the IMTC UC SDN activity group IMTC UC SDN activity group