IP Communications

Years ago, when the concept of Quality of Service (QoS) got going in an effort to make Voice-over-IP (VoIP) phone calls sound as good as conventional toll calls on the Public Switched Telephone Network (PSTN), someone got the bright idea of assigning voice and other “real-time” communications packets a “high priority” so they would be delivered before other classes of service (that is, packets of data that could did not have to arrive in a perfect stream, such as email).

 

One of the early major technologies to provide for such classes of service was MPLS (Multi-Protocol Label Switching). MPLS prefixes packets with an MPLS header, containing one or more “labels”, called a label stack. Each label stack entry contains four fields, one of them being a 3-bit field for QoS priority.

 

MPLS set the stage for how QoS would be handled. Apparently network engineers likened packets to airline passengers – they can travel first-class (high priority), business class (medium priority) and coach (low priority).

 

But some carriers and businesses prefer a finer granularity. The Metro Ethernet Forum (MEF) at one time championed a eight classes of service, and thus concerns began to arise over how to maintain service quality when a carrier with eight classes of service hands off traffic to one with only three classes, or vice versa? It obviously helps if everyone using the services are on the same network.

 

In any case, Global Crossing (News - Alert), a well-known global IP solutions provider, recently announced it will offer six Classes of Service (CoS) - up from three - for its Internet Protocol Virtual Private Network (IP VPN) service. By offering six Classes of Service, Global Crossing now gives customers greater flexibility than ever to prioritize the delivery of applications. Current IP VPN customers will be upgraded from Basic, Enhanced and Premium service to Basic Plus, Enhanced Plus or Premium Plus service respectively, with no price increase.

 

"Global Crossing is dedicated to an excellent customer experience and continues to meet customer requirements with innovative solutions that provide meaningful capabilities," said Gary Breauninger, chief marketing officer. "Having six classes of service gives our enterprise customers a greater ability to ensure uninterrupted transmission of their most time-sensitive and important data, allowing them to control IP VPN performance as they increasingly rely on a single IP-based platform for real-time and converged applications."

 

The growing number of applications using IP requires more classes of service to enable businesses to better prioritize one application's data transmissions over another; if the network is congested, applications that can tolerate delay - such as e-mail - will wait to be sent until more time-sensitive traffic - such as voice - gets through. By stratifying data traffic priority into six Classes of Service, Global Crossing is enabling customers to prioritize all voice over all video, for example, while having both remain in the premium time-sensitive class of service. This also meets the needs of many customers that desire a low priority class of service for Internet traffic and other non-business critical applications that don't require real-time performance.

Global Crossing IP VPN Service™ connects an enterprise's worldwide locations into a single, protected corporate network with true global reach, scalable connectivity, greater security, multiple access options, a broad range of IP communication services, and guaranteed QoS. The standard IP VPN offer with Network Integrity allows enterprises to monitor key performance metrics - in real-time - across their networks via Global Crossing's uCommand® portal. Monthly site-to-site performance reports by the customer's Classes of Service (CoS) are provided as assurance that Global Crossing stands behind, and is compliant with, its performance guarantees. In addition, the standard IP VPN offer alerts users when network performance is affected, providing an immediate proactive notification for their network.