About ten years ago, a cable operator engaged us to help them plan a network operations center (NOC) to manage their planned triple-play services. At that time there were very few tools on the market from which to create a proper NOC; meeting the requirements in our RFP would have required many man-years of custom development.
Over the past year, we've spent time at cable and IPTV trade shows looking at the current tools for triple-play services--especially tools for diagnosing problems with digital video. The good news is that there are now many tools for diagnosing the many things that can go wrong in getting digital video from its source to a consumer's eyeballs. The bad news is that there are so many of them--it's hard to decide what to use.
When we looked at tools ten years ago, only cable operators contemplated offering triple-play services, and service quality wasn't a high priority. Now with satellite competing vigorously for subscription video, and telcos rolling out triple-play services, service quality is one of the key criteria customers use when selecting a provider. The right tools are critical to raising and maintaining consistent service quality in a competitive market.
A Tools Taxonomy
There are so many tools on offer that we found it hard to figure out which tools were trying to do essentially the same thing, and which were doing different things. We found it helpful to sort them into categories. Here's our taxonomy of the tools we've looked at, with a specific example of each type of tool. This is primarily focused on cable, but most of the higher-level tools are equally suitable for IPTV.
Status Monitoring of Active Cable Devices
Status monitoring is the oldest tool in the toolkit. Cable's digital signals are carried to the customer by many linear devices including optical nodes, line amplifiers and power supplies. Early versions of this equipment had proprietary monitoring systems. As standard network management systems such as HP OpenView came into use to monitor IP networks, some cable operators wanted to incorporate the active cable devices in their network views.
The early status monitoring systems acted as adapters to convert the proprietary interfaces in the field equipment into the industry-standard SNMP monitoring protocol, permitting operators to use standard network management systems to monitor their health. Over the years, these systems have evolved from proprietary solutions to using standards-based approaches such as DOCSIS for communications and SCTE-HMS (Hybrid Management Sub-Layer) to define the information exchange.
The Cheetah product line, now made by Tollgrade Communications, is an example.
DOCSIS Network Diagnosis
The DOCSIS management information base (MIB) contains a great deal of useful network-related information, including measurements of power levels and signal to noise ratios. DOCSIS devices include cable modem termination systems (CMTSs), cable modems, MTAs (VoIP CPE) and set top boxes. Every cable home has one or more of these devices continuously collecting information about the network.
Several companies have created systems that poll these devices to present an overall view of the health of the cable network. By reading out the MIBs over time, they can alert problems in the network long before the customer complains.
The ServAssure Advanced Solution Suite, originally developed by Stargus, and now owned by Arris after a series of acquisitions, is an example of this approach.
As opposed to monitoring existing linear and DOCSIS devices, network probes are passive measurement devices inserted into the network to monitor the digital data streams and report on failures.
User Experience Measurement
The latest industry buzzword is "quality of experience" abbreviated "QoE". This connotes measuring the experience (for example, of viewing TV) from the user's perspective, usually subjectively by asking people's opinions of quality. Several companies offer products which claim to provide an objective measure of video QoE, typically by attaching probes to monitor the data streams flowing into a digital set top box.
We've recently been most intrigued by the approach used by Witbe to assess QoE for triple-play services. Rather than connecting probes to the network side of the set top box, Witbe connects to the output side of the box. It controls the box through the remote control interface, and measures the quality of the video and audio in a way that it claims models how a person would assess it. We wrote about Witbe in a recent issue of this report.
What's the Question?
There's a role for all of these tools. If we were asked to design a NOC today we'd probably recommend using many of them.
Which of these tools an operator should deploy and how much to invest in each depends on their answers to some key questions. If I have a new service rolling out, I'd be inclined to focus on things to help me isolate problems and iron them out. If the service is more mature, the focus probably shifts to how much do I want to shift from reactive to proactive management. In a competitive environment, I'd want to focus on whether service is improving or getting worse, and how my customers' quality of experience compares to my competitor's.
Some suitable questions might be: