What Is VoIP QoS and How Does It Make Your Calls Better?

Have you faced call drops or delays during an important client call?

It doesn’t just ruin the conversation, but it can make you seem unprofessional.

If you’re using VoIP (Voice over Internet Protocol) phones for communication, these issues are often caused by poor call quality.

Call quality issues are mostly related to QoS. VoIP QoS is call quality’s best-kept secret.

What is VoIP quality of service (QoS)?

Don’t worry, in this blog, we will explore everything about VoIP QoS, why it matters, key metrics, and recommended QoS settings.

Further, you’ll learn how to set up QoS on your network, best practices to improve VoIP call quality, and more.

Key Highlights

• VoIP QoS is a way to make sure your voice calls remain clear and smooth, even when your network is busy.
• It prioritizes voice packets over other types of traffic in the network.
• It improves call clarity and prevents call disruption by reducing jitter, delays, and packet loss.
• You can set up basic QoS at your home or even a small business by yourself.
• It is not the sole solution for improved communication, but it does make a huge difference in business communication.

What is VoIP QoS (Quality of Service)?

VoIP QoS (Quality of Service) refers to the set of technologies implemented to ensure VoIP calls have greater call quality, reliability, and deliver the best performance across a network.

VoIP uses the internet connection to transmit voice data from one point to another in the form of digital data packets.

Data transmission and conversion both take place in real-time, which makes the process sensitive to delays, interruptions, and bandwidth competition.

In the absence of Quality of Service, you are likely to experience jitter, latency, packet loss, and echo. All of them degrade the call quality and flow of communication.

So, QoS for VoIP, or voice prioritization, is a mechanism to make sure your voice data gets prioritized on your network. The urgent voice packets get VIP treatment over less urgent ones.

Hence, you hear crystal-clear audio quality and encounter fewer dropped calls, even during peak hours.

Why Does VoIP QoS Matter?

With growing reliance on the internet, even minor disruptions can impact communication. For business communication, VoIP supports several communication platforms. VoIP supports voice calls, video conferencing, and unified communication tools.

While handling multiple communications together, your voice calls may face quality issues. In the absence of a robust VoIP quality of service or call quality control, your VoIP network can become congested, resulting in static, broken audio, or dropped calls.

Such poor call quality creates delays and confusion among customers, making them unhappy.

Hence, QoS plays a crucial role as it prioritizes voice traffic over low-priority data so that VoIP calls sound clear and uninterrupted, even if the network is overloaded.

Key Metrics of VoIP QoS

To maintain a high quality of VoIP calls, several performance indicators play a crucial role. The following are the key metrics of VoIP QoS that affect VoIP quality:

A. Latency

Latency refers to the time taken by the voice packets to travel from the sender to the receiver. For voice communication, every millisecond delay disrupts the flow of conversation.

Ideal latency is below 150 milliseconds (ms). If the latency is above 150 ms, you will notice lag and degradation in call quality. This hugely affects real-time voice interactions in contact centers.

QoS reduces latency by prioritizing VoIP traffic, making voice packets reach the destination more quickly.

B. Jitter

Jitter is the variation in the arrival time of voice packets. For smooth communication, all VoIP packets should arrive at even intervals. Due to jitter, data packets may arrive out of order or at irregular intervals.

Hence, the receiving device will have a hard time reassembling the audio. Jitter could be the result of network congestion, route changes, and inconsistent bandwidth.

Saving grace? Jitter buffers. A jitter buffer temporarily stores arriving packets and sends them out evenly to reduce network variability.

C. Packet Loss

Sometimes, the voice packets could go missing during transmission. This could be due to network congestion, poor internet, or misconfigured QoS settings.

Packet loss means missing audio, incomplete sentences, and unintelligible conversation. A greater than 1% packet loss highly degrades the call quality.

So, to maintain VoIP call quality and reduce call drops, you need to monitor your network for any packet loss. Hence, smart QoS setting minimizes packet loss and optimize call quality.

D. Bandwidth

Bandwidth acts as a path for the voice data packets to travel. Greater bandwidth means your voice packets can be prioritized and transferred over the network without delay and disruption.

You need at least 100 kbps (kilobits per second) for each active voice call. Lower bandwidth leads to choppy, delayed, or dropped calls.

QoS settings allow you to prioritize voice traffic over other types. With proper bandwidth allocation, your network will have enough capacity, and VoIP traffic will be prioritized.

E. Mean Opinion Score (MOS)

MOS, or Mean Opinion Score, is a rating of the perceived quality of a voice call by the user, indicating the user experience. It ranges from 1 (worst) to 5 (best); anything above 4.0 is considered good.

For a higher MOS, you need a sound network condition with low packet loss, higher bandwidth, consistent jitter timing, and ideal latency.

While other metrics are technical aspects, MOS is directly related to how the users feel. Hence, MOS matters in VoIP QoS.

Constant monitoring of these VoIP QoS metrics helps your network performance support clear, reliable, and professional VoIP communication for your business.

How Does VoIP QoS Work?

The goal of VoIP QoS is to make sure your voice packets reach the destination or receiver on time, in order, and intact.

Without call quality control, since all types of network traffic require space, VoIP does not get prioritized, leading to a communication mess. QoS solves this issue by enabling voice packets to get fast-tracked even when your network is busy.

Here’s a breakdown of how VoIP QoS works:

1. Traffic Classification and Marking

First, the network should identify the voice packets among all incoming traffic. DSCP (Differentiated Services Code Point) does it perfectly. It marks each packet with a tag demonstrating its importance to the routers and switches.

For urgent ones like VoIP packets, it marks with high-priority codes like DSCP-46 (Expedited Forwarding or EF), signaling the device its importance and urgency.

2. Traffic Prioritization

Once the marking is completed, voice packets receive VIP treatment. They can skip the queue and get transmitted with minimal delay, called expedited forwarding. A technique called Priority Queing (PQ) frontloads the voice traffic.

Next, Class-Based QoS (CBQoS) gathers all voice packets in a particular lane or class to surpass the regular queueing.

3. Bandwidth Reservation and Traffic Shaping

Appropriate bandwidth is a must. Without enough bandwidth, even prioritization can not save the voice traffic from quality dips. Therefore, QoS secures the necessary bandwidth for VoIP traffic.

Traffic shaping maintains the data flow fluctuation to prevent issues like packet loss or jitter.

Likewise, rate limiting slows the low-priority traffic during peak hours to dedicate a special path for emergency VoIP packets.

4. Queuing Mechanism

Next, the queueing technique determines how each data packets are handled. These queuing algorithms play a crucial role in maintaining call quality.

Example:

• FIFO (First In, First Out): Packets are processed based on the order of their arrival. This is not suitable for VoIP.
• WFQ (Weighted Fair Queuing): It assigns a weight to the traffic flows with a fair share of bandwidth for each. Better than FIFO, but does not give precedence to voice packets.
• LLQ (Low Latency Queuing): Puts voice traffic in top priority, simultaneously managing other data types.

5. End-to-End Configuration

You need QoS configuration on all of your devices for QoS to be effective. From IP phones and softphones, routers, switches, firewalls, access points, to an Internet Service Provider (ISP), every device connected along the path needs to recognize QoS settings.

A single device ignoring QoS markings can turn out to be an obstacle, leading to jitter, delays, or dropped packets.

Therefore, VoIP QoS works through traffic identification, classification, marking, prioritization, bandwidth reservation, and a queueing mechanism. This ensures voice packets are prioritized so VoIP call quality is maintained.

Recommended VoIP QoS Settings

For a QoS to work well, it needs to be well-configured. So, here are your recommended VoIP QoS settings for a good QoS configuration:

• Mark Voice Traffic as Important (DSCP EF): This involves labeling each voice packet with a priority tag. It indicates that VoIP packets should be the top priority on the network.
• Trust the Tags (Trust Mode): Enable trust on switch ports. This tells your network devices to honour the DSCP marking and believe the tag.
• Strict Priority Queueing: Let voice packets go first. This helps voice packets skip the queue and get expedited during peak hours, preventing delay or disruption in calls.
• Bandwidth Allocation: Save bandwidth just for calls. You reserve part of your internet connection for voice data, so when there is too much traffic on the network, at least 100kbps can ensure a smooth VoIP call.
• Handle Small Delays Smoothly: A Jitter Buffer temporarily stores voice packets to reorder them and avoid any inconsistent deliveries. This prevents your voice from sounding choppy or robotic.
• Use Router Templates for Easy Setup: Many routers come with built-in VoIP settings, such as Fortigate, Meraki, pfSense, and others. So, look for voice templates in your router settings and enable them.

Think of VoIP QoS like giving your phone calls a VIP ticket for safe and accurate transmission over the internet; no delays, no interruptions.

How to Set Up QoS on Your Network?

Setting up QoS on your network isn’t rocket science. You can do it even if you’re not tech-savvy.

To set up QoS on your network, follow these simple step-by-step guide:

1. Identity VoIP Traffic

First, your router needs to identify the call. Most VoIP calls use port 5060 (UDP) for call setup and ports 10000-20000 for the actual voice. So, in your router, you can create a rule saying, “Traffic using UDP port 5060 = VoIP.”

Use ports or the destination IP of your VoIP service provider, like Dialaxy.

2. Log into Your Router or Firewall Settings

Routers like Edgerouter Lite, USG, or DD-WRT offer admin panels like a control panel for your internet.

So, open a browser and type your router’s IP (something like 192.168.1.1). Then, enter your username and password to access the admin panel.

3. Set Rules to Prioritize VoIP

Now, you can prioritize your traffic based on port, IP address, or DSCP tag. This makes sure VoIP traffic is put first every time.

This is like creating a QoS rule saying, “If it is voice traffic, always give it high priority.”

4. Reserve Bandwidth for Voice Calls

Just like a VIP seat reserving system, you can secure some part of your internet bandwidth only for voice over IP.

A safe practice is to reserve 100 kbps per VoIP call. You can assign sufficient bandwidth using a slider, a number box, or a “Guaranteed Bandwidth” setting.

5. Turn On Monitoring Tools

Regular monitoring of QoS is important to ensure smooth calls. Some routers let you see how much voice traffic is being used. You can also track the VoIP QoS test results and optimize your settings accordingly.

In case your router does not have those features, you can use free tools like PingPlotter and VoIPmonitor.

Setting up QoS might seem fully technical and a daunting task, but it is doable. Even if you’re not a tech expert, you can do it following these simple steps.

Once it’s done, you will be ready for smooth, uninterrupted, and professional communication.

Monitoring and Troubleshooting VoIP QoS

Even after you’ve set up QoS, you need to regularly monitor and troubleshoot issues to make sure your calls are smooth.

Here’s how you can monitor and troubleshoot QoS:

How to Monitor VoIP QoS:

• Use VoIP monitoring tools, such as Wireshark, PingPlotter, or VoIPmonitor, to check call quality by keeping an eye on latency, jitter, and packet loss.
• Perform timely VoIP QoS tests to ensure your setup is working well.
• Monitor bandwidth limitations that could affect your network performance.

How to Troubleshoot QoS Problems:

• Check if QoS settings are properly applied.
• Check for old or outdated network equipment. Upgrading them can help improve call quality.
• Limit background downloads that increase data traffic. Consider pausing or post-scheduling the less important updates and backups if you face a call disturbance.

Initial setup of QoS can enable smooth calls, but you will have to monitor it regularly to track any issues and prevent them from degrading your call quality.

VoIP QoS Limitations You Should Know

Now that you know QoS can drastically improve your VoIP calls, you may think that configuring QoS solves all the problems. But is that true?

Sadly, there are still a few limitations of QoS. It may give you call clarity, but at a cost. Before you take an instant decision to implement VoIP QoS, let’s take a moment to understand its practicality.

I. Limited to Local Network Control

QoS settings are valid only within your own infrastructure. It applies only between your IP phones, routers, switches, and firewalls. The VoIP packets leaving your premises over the public internet will be out of your control.

No perfect internal QoS can ensure high call quality throughout the process, as external factors have their own impact. The voice data will still suffer latency, jitter, and packet loss.

II. Dependent on Network Hardware Capability

The functionality of QoS is highly dependent on the hardware and networking devices. Old and outdated devices may not support advanced QoS features like DSCP tagging and priority queueing.

You will need to monitor and upgrade your devices for the effective implementation of the QoS policy.

III. Cannot Compensate for Insufficient Bandwidth

QoS optimizes allocated or available bandwidth. But resolving any issues originating from an insufficient or undersized internet connection is off the table.

If your available bandwidth is already too low for concurrent voice and data usage, call quality will surely take a hit. So you need adequate bandwidth along with QoS. They cannot act independently.

IV. No Influence on External Network Routing or Latency

Next, external network routing or latency is also out of bounds. QoS cannot interfere with how your data travels across the public internet or cloud services.

The internet controls the routing path. QoS cannot fix latency caused by long physical distances between endpoints, slow routers, or peering problems between ISPs. It also cannot fix external congestion or bottlenecks.

V. Requires Continuous Monitoring and Maintenance

If you’re thinking you could get a lifetime benefit after QoS configuration, sadly, it is not the case. QoS requires consistent monitoring and adjustments. You need to monitor network devices, perform periodic QoS tests, and upgrade old devices.

In the absence of regular monitoring, prioritization rules may become outdated, and new types of traffic might interfere with voice calls, resulting in disrupted calls.

VI. Limited Compatibility with Certain Devices and Applications

Not all devices honour QoS tags like DSCP markings. Some consumer-grade apps and devices may strip QoS tags, mark all traffic the same, or bypass classification rules.

This can undermine the effectiveness of your prioritization setup, especially in mixed hardware environments.

Therefore, VoIP QoS may sound like a magic tool, but it has its drawbacks. It may improve your voice calls, but it does not give you control over external networks. Hence, you need to keep these things in mind before implementing it..

VoIP QoS for Small Business and Remote Teams

Small businesses and remote teams mostly rely on shared or home networks. This causes the bandwidth to be distributed across various file downloads, video streaming, gaming, and office work.

That is why VoIP QoS is essential. It helps ensure important voice traffic from business communication is prioritized over less urgent data to keep your voice calls clear and smooth, even when the network is busy.

Here’s a breakdown of how small and remote workers can make the most of VoIP QoS:

• Use a VoIP QoS Router: You can invest in a router that supports QoS for VOIP. Whether for home or office, these routers are suitable as they can automatically identify and prioritize voice data, improving your call quality.
• Upgrade Network Devices: If you own a small business, always choose network equipment that supports advanced QoS settings. These tools help you gain more control over how network traffic is handled.
• Run VoIP QoS Tests: You can check for issues such as latency, packet arrival, and packet loss by running timely tests. Through these tests, you can identify problems before they generate disruption in communication.
• Choose a QOS-Enabled Contact Center Solution: For customer support or sales, you should look for a contact center solution that has built-in traffic prioritization. With this, your voice call is sure to be clear and uninterrupted.

Hence, for remote teams and small businesses that need to rely on limited resources and budget, getting VoIP QoS can be a game-changer.

Always choose a reliable and established VoIP service provider like Dialaxy. Dialaxy makes sure you enjoy smooth business or personal communication with high call quality at a reasonable pricing plan.

Best Practices to Improve VoIP Call Quality

Just setting up QoS is not the end. For high call quality, you need to adopt some best practices.

What can you do to improve your VoIP call quality?

Here are some practical and easy-to-follow tips to keep your VoIP communication running smoothly.

• Upgrade your router to one that supports QoS for VoIP. A business-grade router like Meraki VoIP QoS is designed to handle VoIP networks, bandwidth management, and traffic shaping, which maintains consistent call quality.
• Always use Ethernet for VoIP phones. For the best VoIP quality, use Ethernet cables over WiFi. A wired connection is more secure for low latency, less jitter, and stable network performance.

• Set a bandwidth limit for non-essential devices. Your downloads, streaming services, and smart devices hog your bandwidth. With QoS, you can put limits on less urgent traffic, so voice data has enough bandwidth.

• Keep network equipment firmware up-to-date. Since network devices receive performance and security through firmware, you need to habitually check for updates and apply them across all devices.
• Use QoS monitoring tools. Identifying issues beforehand by tracking key metrics will allow you to resolve them without hampering your call quality.

Make sure you apply these practices for better VoIP call quality. These techniques are bound to give you clear and smooth professional call quality. With QoS, you will handle business communication like a pro.

Conclusion

So, what is VoIP QoS?

It is the holy grail for improved call quality. It is a set of techniques to prioritize voice traffic over other types of traffic.

Your voice calls will be prioritized like VIP to ensure smooth voice data transmission. You don’t have to deal with poor network performance, disrupted calls, and bandwidth issues.

At Dialaxy, we make sure, with a small investment, you can get high-quality voice calls and improve business communication with your clients and customers.

With QoS settings, your VoIP communication will reach the next level.

So, are you ready to upgrade your VoIP communication with Dialaxy?

FAQs

What are the metrics for VoIP QoS?

Its key metrics are latency, jitter, packet loss, bandwidth, and MOS (Mean Opinion Score).

What is the DSCP value of VoIP QoS?

The commonly used DSCP value is DSCP 46.

What are three QoS issues for a VoIP application?

The three common QoS issues for a VoIP application are high latency, packet loss, and jitter.

What happens if there is too much latency in a VoIP call?

If latency exceeds 150 to 200 milliseconds, users experience delays in response, echo, or people talking over each other, and a breakdown in natural conversation flow.

What is the minimum set of one-way QoS values for a VoIP exchange?

The recommended minimum one-way QoS values for VoIP are latency ≤ 150 ms, jitter ≤ 30 ms, packet loss ≤ 1%, and MOS ≥ 4.0.

How do I know if my QoS settings are working?

You can determine if your QoS settings are working by analyzing your call quality, VoIP QoS tests, monitoring network performance tools like Wireshark, and ensuring voice traffic is getting top priority in your network.