Connectivity Problems? Measure Network Effectiveness Ratio


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Several metrics measure the performance of your network, but the network effectiveness ratio (NER) is among the most important. NER simply measures a network’s ability to deliver a call to a destination device, terminal, or recipient. This measurement is evaluated by the number of calls a network sends versus the number of calls that get delivered. 

However, NER doesn’t exclude any user actions that contribute to call rejections from the equation. By including user failure actions, NER subsequently counts ignored calls (rings with no answer), busy signals, and calls sent to voicemail as successful call deliveries.  

Another measure of network quality is known as the answer seizure ratio (ASR). This metric is calculated by obtaining the total number of answered calls and dividing it by the total number of attempted calls (known as seizures). While ASR is a vital metric, it isn’t as important as NER. 


Both NER and ASR are used to evaluate network quality, but their most glaring difference is how they account for terminal and customer behavior. 

Basically, since ASR counts call rejections and busy signals as failures, its value is greatly affected by user action. For this reason, it’s also known as the call completion rate, as it only indicates your network quality based on total call volume and call success rates.

Meanwhile, by not allowing user-based behavior to affect its value, NER more accurately represents the true performance of a given network. At the end of the day, it measures network quality better by strictly focusing on the percentage of call failures that were the result of network problems—and it doesn’t care if a customer rejected a call because that’s not the network’s problem. 

Nevertheless, despite being the best metric for network performance, NER isn’t used in the industry as much as ASR, especially when evaluating VoIP phone service route quality. One speculatory explanation for this could be that once NER is reliable enough, a call center won’t have to worry about it as much.

To calculate NER, use this formula:

NER % = 100 x (Answered calls + User Busy + Ring no Answer + Terminal Reject Seizures)/Total Calls

To calculate ASR, use this formula:

ASR % = 100 x (total number of answered calls / total number of calls)

How Network Effectiveness Ratio Works

NER calculates successful call delivery by considering busy signals but excluding call failures due to user behavior, such as rejecting a call or allowing it to go to voicemail. Therefore, NER represents call attempts or seizures that result in an answer signal. 

On the technical side of things, getting an accurate measurement of NER is more complex, especially compared to ASR, as it requires more complete signaling.

The Integrated Services Digital Network User Part (ISUP) is an international signaling protocol that can be used as the foundation for measuring NER. It verifies the availability of network resources and allocates the channels responsible for the call.

The following sequences are required to place a call and capture NER:

  • ‘This is an answered-call event’ indicates a successful call sequence because the activity was completed and the call was successfully placed.
  • ‘This is a no-answer call event’ indicates that a user successfully made the call and the activity was completed, but the RNA (Ring No Answer) timeout limit was reached.
  • ‘User busy’ indicates that the call activity was completed, but the line was busy.

As per the International Telecommunication Union’s ITU-T Recommendation E.425, which describes the internal monitoring of network performance, NER unveils the problem between two networks. Regarding the far end of the network in particular, ITU states that if your network receives error code replies of “User Busy,” “RingNoAnswer,” or “Terminal Rejects/Unavailability,” they aren’t the culprits of plummeting NER values. 

In other words, this is just the official documentation indicating that NER expresses network quality without considering busy or error code replies.

Common Call Center NER Applications

While NER measures the ability to deliver calls, it also provides vital information like subscriber behavior and network signaling faults. To get the best mileage from NER’s “successful call delivery” quality metric, contact center operators should use it to assess call center and agent performance. 

Improving agent performance using NER insights

Call centers can leverage NER to evaluate and understand things related to agent performance, such as whether to offer callback options to customers, especially during peak times, to better assist agents. 

The call center can also decide to offer omnichannel support to provide more avenues for successful call deliveries. These can include self-service options and AI-powered chatbots.

An organization can use the feedback provided by NER calculations to optimize its call center’s effectiveness. For example, you can use NER knowledge to alleviate agent workload and reduce customer wait times by targeting optimum staffing levels. While popular metrics like call abandonment rate aren’t NER values (since they occur due to user behavior), they nonetheless provide clues to the overall call center experience. 

Therefore, analyzing NER calculations allows call center organizations to make educated staffing decisions, empower their agents, and offer superior training and guidance.

Tools for NER calculation and monitoring

Tools such as Microsoft’s Health Dashboard for Direct Routing and Khomp SBC media gateways are useful for troubleshooting calls. These tools should allow you to monitor your call center’s KPIs, especially those that measure agent productivity.

Health Dashboard for Direct Routing allows you to monitor information on a telephony service like Voice over Internet Protocol (VoIP) and network parameters. Technically, it does this by monitoring the connection between the Direct Routing interface and the Session Border Controller (SBC). 

SBC controls the admission of phone calls— whether through network carriers or VoIP—by providing access control and data conversions for calls as they move in or out of the network. 

The SBC protects and regulates IP communications, especially collaborative sessions with real-time communications using IP video, chat, and VoIP. You can deploy SBC as a hardware or software tool to test voice lines to ensure high quality and manage how calls are initiated, conducted, and terminated.

While Direct Routing allows you to troubleshoot call connectivity and evaluate whether your network is performing as planned, Khomp SBC media gateways are intelligent platforms for contact center operations. 

The Khomp SBC provides access to data on various metrics, such as NER, ASR, average call duration (ACD), and call attempts per second (CAPS). However, it also goes the extra mile by using multiple analytics filters to combine values (NER, ASR, ACD, and so on) in real time. It even scales your ability to monitor call center operations regardless of size.

Some other tools for calculating NER include:

  • Session Border Controller
  • ControlSwitch System
  • Diameter, SIGTRAN & SS7 Components
  • I-Gate 4000 Media Gateways

Potential NER Challenges in a Call Center Environment

Businesses use several metrics to gauge the effectiveness of their call centers. However, calculating NER requires understanding which metrics are pertinent and which are irrelevant.

For instance, the call abandonment rate tells you the average number or percentage of callers who hang up or give up on their calls before reaching an agent or resolving an issue. Of course, this won’t factor into NER calculations because it depends on user and customer behavior.

Remember, metrics that involve callers hanging up or disconnecting are irrelevant for NER, although you can use them for ASR.

Critical KPIs to Keep an Eye On

There are many crucial KPIs that impact call center effectiveness, most of them dealing with customer experience, agent performance, and call center performance metrics. 

NER is mainly concerned with your network’s ability to deliver calls, but it still has an impact on many relevant KPIs.

Customer experience metrics

  • Customer satisfaction (CSAT). As its name implies, CSAT is used to evaluate customer satisfaction, which is typically measured through surveys that capture how users feel about their interactions with call center agents and the assistance they receive. 
  • Net Promoter Score (NPS). NPS measures customer and brand loyalty. It is typically administered quarterly or bi-quarterly via surveys regarding long-term satisfaction. NPS does this by categorizing customers with decreasing levels of engagement as promoters, passives, and detractors.
  • Customer Effort Score (CES). The operative word in CES is effort because it represents process friction. CES judges how hard customers must try to resolve their issues or to reach an agent. 
  • First contact/call resolution (FCR). Since first impressions matter, call centers don’t want customers to make repeated calls or follow-ups because of how negatively it can affect their experience. Therefore, a high FCR rate reflects greater user satisfaction because it indicates that customers are getting their problems solved efficiently. 

Call center and agent performance metrics

  • Average call duration (ACD) signifies the average length of time agents spend on a support call. Its duration positively correlates with NER, indicating good contact center connectivity. While call centers generally want to optimize their resolution speeds, they don’t want customers to feel like agents are brushing them off. 
  • Average speed of answer (ASA) measures the time it takes for a contact center to respond to inbound calls. Customers prefer to have their calls answered quickly by an agent or representative.
  • Active waiting calls measure the number of customers who have to wait on hold. Your call center should aim to connect callers with agents with as little hold time as possible. 
  • Call arrival rate measures the frequency of calls received during a period. This could be per minute, hour, day, week, month, or year.
  • Blocked call percentage captures how often incoming customers receive a busy signal. This percentage doubles as a call center and customer experience metric, and it’s good to keep its value low so that customers aren’t greeted by a busy tone when they call.

What to Do After NER Detects Low Call Quality?

VoIP software is the easiest and most practical way to resolve low call quality, especially for call centers. VoIP is a handy tool for manipulating internet packet delivery to improve calling clarity, responsiveness, and quality.

VoIP is ideal for call quality monitoring and troubleshooting because its process is straightforward to identify and trace. Fundamentally, VoIP is a technology that converts the raw audio from your voice into a digitized stream.

The process typically uses codec applications that compress the audio stream into multiple digital data packets for efficient transmission. The data packets then travel through IP networks via a switch or router to their endpoint destination.

On the receiving end, this process is reversed—meaning a codec performs the decompression, and data packets are converted back into audio at the receiving end.

VoIP quality tests

If your contact center is experiencing low call quality, you can take some steps to improve the situation—or at least identify some potential causes of the problem. For instance, VoIP quality tests allow you to measure and evaluate the most vital metrics responsible for call quality. 

Keep in mind that you can perform VoIP speed tests with tools and solutions such as Nextiva.

Factors that contribute to low call quality

To resolve poor quality in VoIP, you must understand the three fundamental factors that contribute to it.

  1. Packet loss can occur for various reasons, but it mostly results from a network being too busy or having limited VoIP bandwidth requirements. Networks tend to drop data packets when delayed or lost, resulting in calls with missing chunks of audio or eerie bouts of silence. 
  2. Jitter is a form of variable packet delivery that prevents a network or device from transmitting or playing an audio stream at a constant rhythm. Interruptions to the data stream ultimately reduce call quality, which is irritating to both parties. 
  3. Latency (or end-to-end network delay) is when your network packets don’t arrive on time or at the same interval. Network congestion is one of the primary problems that cause latency, so you should find ways to eliminate unnecessary traffic or activity.  
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