Monitoring and T&M Transformed in the IP World

The old saying goes something like, "With great opportunity comes great responsibility." That's true. A corollary could be: "With great opportunity comes great challenge - and headaches." Monitoring and test and measurement of advanced video platforms is a perfect example.The new reality is rife with complexity: More channels, more devices to which to deliver the content and more ways of sending. One change alone - that programming is becoming far more widely available on an on-demand basis - is a quantum leap that radically increases the difficulty of what operators do.One thing hasn't changed, however: It still is the operators' responsibility to have monitoring and test and measurement systems in place to ensure that all of that programming is getting to where it has to go - which could be a tablet hundreds of miles from the subscriber's home.The depth of the task is clear to Steve Liu, the vice president of video network monitoring at Tektronix. Liu laid it out in response to emailed questions: "The procedures haven't changed significantly, but since there are new and multiple ways to deliver video to consumers, monitoring and T&M equipment will have to change and adapt in order to be able to continue to ensure highest video quality delivered to more different devices (in addition to TV) in multiple screens."The differences in the challenges between monitoring and test and measurement a generation ago and today are so extreme that a compare-and-contrast can miss the point. One overriding transition that illustrates the changes is the movement from quality of service (QoS) to quality of experience (QoE). QoS focuses on pure metrics: If certain levels are met and parameters kept intact, all is fine. QoE uses such metrics, but moves beyond to assess the actual images and sounds that a subscriber is getting.An illustration shows simply where QoS falls short in the modern landscape. IP video utilizes adaptive bitrate streaming (ABS) to serve subscribers. A major element of ABS is the idea of "profiles" - that the amount of data sent to an end device is appropriate for the nature of the device, the capacity of the network, conditions on that network at a specific point in time and other variables.Thus, somebody watching IP video on a big screen TV on a high quality managed IP network would be served by a far different profile than somebody watching on a tablet on the unmanaged Internet. If a problem of some sort erroneously sent the tablet-level profile to the big screen set (but nothing else was amiss), QoS measures wouldn't necessarily detect a problem: After all, bits are getting from point A to point B. Of course, the big screen set owner wouldn't be satisfied with the images and sound produced. QoE platforms are intended to recognize and diagnose such situations.The problem in such a scenario likely will be in an area that has been added once IP video became common: The files that are used to help packets navigate the complex landscape. "There are player metrics that measure QoE," said Jim Welch, the principal engineer for Ineoquest. "If [the] transcode process is corrupted, or the stream or index manifest file is corrupted, what's on the screen may not be satisfactory."At the highest level, the transition the industry is going through is deeply enmeshed in the move from a totally multicast environment to a hybrid multicast/unicast environment. "If one subscriber has an issue grabbing a video, is that really the end of the world as opposed to HBO going down?" asked Dave Hering, the product line manager in JDSU's (NASDAQ:JDSU) Communications Test and Measurement business segment. "If HBO goes down, all is lost. It is a question of of how important each session [is] and how important it is to fix it the second it happens."Problems in a unicast environment are more likely to be harder to identify. In other words, everyone knows the moment HBO goes down. In a unicast streaming environment, things are not as immediately obvious. "There's going to be more root cause analysis to see if there is a problem with the asset, or with some mobile device the operator supports, or a problem with a portion of the network [or other problems]," Hering said.Carl Weinschenk is the Senior Editor of Broadband Technology Report. Reach him at [email protected].