Active Synthetic Network Monitoring: What It is and Why It Matters

Posted by Natalie Mountain on Tuesday, November 07, 2017 with No comments


When it comes to tracking and optimizing the performance of wireless networks and the services they support, what’s more important: passive monitoring or active (synthetic) monitoring? The short answer is that both play a role. However, given the increasing complexity of modern broadband wireless networks, and the direction in which they are evolving, it’s fair to say that active monitoring plays a more and more important role. As such, it’s important to understand how it compares to and complements passive monitoring, and why it matters.

Active monitoring simulates the network behavior of end-users and applications, monitoring this activity at regular intervals — as fast as thousands of times a second, if required — to determine metrics like availability or response time. It is a precise, targeted tool for performing real-time troubleshooting and optimization.

By contrast, passive monitoring analyzes existing traffic over time and reports on the results. It is best for predictive analysis using large volumes of data, identifying bandwidth abusers, setting traffic and bandwidth usage baselines, and long-term traffic analysis to mitigate security threats.

Why Active?

Cloudification, encryption, decentralization and SD-WAN have fractured the value of traditional, passive monitoring. As a result, blind spots are consuming both networks and services, with service providers losing sight of the majority of traffic.

Where visibility still exists, it’s insufficient. Compute and hardware-intensive passive solutions are slow to report, typically taking well over a minute to digest and produce metrics. But, today’s dominant traffic flows—software as-a-service (SaaS), web, social media, streaming media, and real-time communications—are dependent on significant volumes of transient sessions between servers and clients, cloud and apps.

Consider, for example, that 90% of all TCP sessions last less than 3 seconds, and consume less than 100 bytes each. It’s not surprising, then, that the majority of network downtime is from short term degradation, not sustained outages. Passively monitoring aggregate traffic, reported every few minutes, miss the vast majority of short term events that impact the services subscribers use the most.

Active monitoring takes a proactive approach, overcoming these visibility gaps, while delivering the enhanced precision, and the sub-second insight required to monitor and assure dynamic services. Active-synthetic monitoring is a lightweight, ubiquitous and standards-based approach that faithfully replicates application and network traffic with unrivaled precision and frequency. This creates a constant, controlled source of detailed metrics that accurately characterize quality of service and experience (QoS, QoE).

Active Monitoring Uses

Beyond its broad use as a controlled, targeted, QoE optimization tool, active monitoring is valuable for:


  • Introducing new services. VoLTE, Internet of Things (IoT), SaaS, over the top (OTT) and other digital services can be simulated and monitored, throughout their service lifecycle. Active test allows service providers to assess network readiness before deployment, and the impact new services have on other applications when they go live and begin to consume the network. 
  • Applying the benefits of virtualization to network and service assurance. Active monitoring is easily virtualized. When surveyed by Heavy Reading, service providers overwhelmingly pointed to active testing, and virtualized agents, as driving their quality assurance efforts and budgets. Passive probe appliances were the most likely to lose budget, after years of consuming significant capital expenditure. Most passive solutions are nearly 500% more expensive than the active solutions enabled by virtualization.
  • Enabling automated, software-defined networking (SDN) control. Active monitoring provides a complete, high definition view of end-to-end performance that service providers can use as real-time feedback for automated control, and with machine learning and artificial intelligence (AI) for root cause analysis, predictive trending, and business and customer journey analytics. Exceptionally granular, precise data with a wide diversity of statistical perspectives means analytics can converge and correlate multi-dimensional events an order of magnitude faster than coarse, passive monitoring data permits.
Breaking this down further, the advantages of active monitoring include:

  • Massive, multinational network monitoring scalability on lightweight, virtualized compute resources
  • Carrier-grade precision that enables undisputed service level agreement (SLA) reporting, independent of traffic load or location
  • Ability to resolve detailed, one-way measurements to microsecond precision
  • Ability to measure performance, QoS, and QoE at any location, physical or virtual, end-to-end
  • Tests can be targeted at known issues, locations or services on demand to accelerate troubleshooting
  • Streaming metrics tailored to machine learning, analytics, artificial intelligence (AI), automated SDN control and management and network orchestration (MANO)
  • Ability to proactively and predictively test services before they come online: VoLTE, IoT, business services, SaaS, and impact of OTT
  • Fully standards-based, and interoperable over multi-vendor, multi-domain infrastructure
  • Eliminates the need for taps, packet brokers or “SPAN” ports
  • Segments networks and services to allow rapid fault isolation, precise trending, and predictive forecasting
  • Proactive, in contrast to passive monitoring which is always “after the fact”
  • The ability to baseline and threshold using reliable and consistent data
  • Predictive mechanism to facilitate network improvements/adjustments based on subtle changes/symptoms vs. customer complaints
Passive monitoring still plays a role in managing and optimizing wireless networks, and always will. But, the complex nature of these networks today and tomorrow also demands the use of active monitoring for real-time, proactive, automated QoE optimization. Don’t leave home without it!
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