Lora O'Haver
Senior Solutions Marketing Manager
Blog

Subscriber-Aware Session Monitoring: The ABCs of Network Visibility

May 9, 2019 by Lora O'Haver
Subscriber-Aware Session Monitoring

This blog is another in a series devoted to exploring critical aspects of network visibility. The topic this time relates to how service providers can use network visibility to develop an understanding of the experience of an individual subscriber. In our competitive and highly-digital world, customer knowledge is a powerful driver of business success.

FUNCTION OF SUBSCRIBER-AWARE MONITORING

To remain competitive, service providers strive to personalize residential and mobile services for their subscribers. Each service has different requirements in terms of packet delay tolerance, acceptable packet loss rates, and required minimum bit transfer rates. Subscriber-aware monitoring provides the per-subscriber visibility, policy enforcement, and quota management necessary to customize service offerings and maximize service revenues.

Troubleshooting in this environment can be challenging for operators. It can take engineers days to search the database of the monitoring system for a single customer’s traffic before analyzing it. Subscriber-aware packet filtering can reduce the time and cost of troubleshooting by filtering, correlating, and aggregating traffic from one customer or a group of customers.

TYPICAL USE CASES AND BENEFITS

Typically, operators monitor their networks using monitoring probes—specialized devices that generate important metrics about quality of service (QoS) of the network, such as:

  • Average quantity of data consumed by a subscriber
  • Delivery type, such as video streaming 
  • Measure of voice quality 
  • Percentage of calls dropped

Probes can be either physical or virtual. However, monitoring probes are limited in their ability to scale out and handle the vast amount of traffic in modern networks. It is not efficient to use the limited capacity of probes to try and aggregate traffic by subscriber. Increasingly, operators use intelligent packet brokers to aggregate session data across all links and see inside traffic that has been encapsulated for easier transmission. Correlating user sessions, as users roam from network to network, has become a critical need as well. The following are key use cases for subscriber-aware session monitoring:

Assure QoS and QoE

The best way to maintain and improve QoE is to have visibility to subscriber activity across the radio access and core networks. Many of the problems in service fulfillment, including the inability to identify bottlenecks and proactively deal with delivery failures, can be traced to a lack of subscriber-level traffic visibility. The insight derived from greater visibility reduces the number and severity of errors, expedites failure resolution, improves the speed and reliability of service activation, lowers costs, and enhances the customer experience.

Ease network congestion

Additional transmission lines, fatter pipes, and improved efficiency are common responses to network congestion. However, these traditional tactics are not sufficient for managing wireless networks. While increasing capacity with additional spectrum and spectrum efficiency are important, capacity improvements alone with not solve the complex challenge of ensuring QoS for wireless services. Instead, proactive management policies that prioritize real-time traffic such as VoIP over file sharing will minimize dissatisfaction for users.

Support new business models for service monetization

The ability to efficiently charge for the consumption of resources is an important competitive advantage for service providers. Operators must look beyond connectivity and tiered plans to find sustainable business models. Granular subscriber-level visibility is the key to monetizing new services. With better data on subscriber usage, location, device, time and date, and resources consumed, providers can identify new revenue opportunities.

Reduce cost of troubleshooting

Troubleshooting subscriber issues in such a complex and high-volume environment is challenging for network operators. It can take them days to search the database of the monitoring system for a single customer’s traffic before analyzing it. Subscriber-aware packet filtering can reduce the time and cost of troubleshooting by filtering, correlating, and aggregating traffic from one customer or a group of customers.

CONSIDERATIONS FOR SUBSCRIBER-AWARE MONITORING

GTP correlation

GRE tunneling protocol (GTP) is a group of communication standards used to allow end-users to move from place to place in a network without losing fidelity. A visibility platform with GTP correlation can access subscriber data inside GTP tunnels and ensure all of the data for a single subscriber session is delivered to the same monitoring tools or probes.

At the same time, the GTP controller can allocate bandwidth to enforce capacity and rate limits for each user, even as rates fluctuate. If the controller detects faulty or overloaded monitoring probes, it automatically redistributes the load to other probes in the cluster. As a result, monitoring probes are able to focus on QoE analysis rather than spend cycles trying to reassemble GTP session traffic.

Data for flow collectors

Service providers use sophisticated tools known “flow collectors” to analyze network data and provide insight about subscriber and application usage. The more detailed the data you give to flow collectors, the greater the insight they provide. A network visibility solution provides flow collectors with granular packet data such as subscriber information, application information, HTTP metadata, data volume, timestamps, and source and destination addresses.

Application identification

Subscriber services can be controlled dynamically provided the visibility solution is able to identify the application being requested by the subscriber. A visibility solution with Layer 7 application intelligence can determine whether the subscriber’s data packets match a particular application signature and apply the appropriate policy. Ixia Vision ONE solutions have an extensive library of predefined application signatures that are regularly updated.

Usage monitoring

A visibility platform can provide the data needed to monitor the volume of traffic or amount of time a subscriber uses during a session. This information is needed by the policy and charging rules function (PCRF) to manage subscriber billing.

Support for subscriber-aware sampling

As data volumes explode, it is more difficult and expensive for providers to continue full data analysis of all incoming traffic. As a result, new technologies let the visibility platform forward a statistically- representative sample of subscriber activity to monitoring tools and probes. The integrity of subscriber data is preserved by forwarding all the flows associated with the sampled session.

SUMMARY

Subscriber-aware session monitoring gives service providers valuable insight for optimizing quality of service (QoS) and experience (QoE) for mobile or fixed-line subscribers. A visibility platform with this functionality can identify and aggregate a user's session data and give operators the opportunity to amaze and delight their customers with an experience tailored for them.