How do you choose between packet scheduling and packet shaping for QoS?

1 What is packet scheduling?

Packet scheduling is a QoS technique that determines the order and timing of packets that are sent or received by a network device, such as a router or a switch. Packet scheduling can assign different priority levels to different types of traffic, such as voice, video, or data, and ensure that the most important or sensitive packets are processed first. Packet scheduling can also prevent congestion and buffer overflow by dropping or delaying low-priority packets when the network is busy.

2 What is packet shaping?

Packet shaping is a QoS technique that controls the rate and volume of packets that are sent or received by a network device, such as a firewall or a gateway. Packet shaping can limit the bandwidth allocated to certain types of traffic, such as peer-to-peer or streaming, and enforce policies or agreements on the network usage. Packet shaping can also smooth out traffic bursts and spikes by buffering or delaying excess packets until the network is less congested.

3 Advantages of packet scheduling

Packet scheduling has several advantages for QoS, including improved quality and reliability for real-time applications like VoIP or video conferencing. It can also prioritize the most critical or interactive traffic, such as web browsing or online gaming, over less urgent or background traffic. Additionally, packet scheduling can increase the network efficiency and utilization by optimizing the use of available resources and avoiding wasted bandwidth.

4 Disadvantages of packet scheduling

Packet scheduling can have some drawbacks for QoS, such as introducing complexity to the network configuration and management, creating conflicts between different network segments, and causing unfairness to low-priority traffic. This is due to the need for defining and applying priority rules and queues for different traffic classes, using different packet scheduling algorithms or parameters by different network operators, and dropping or delaying low-priority traffic when the network is congested. These issues can affect the performance or functionality of some applications or users.

5 Advantages of packet shaping

Packet shaping offers several advantages for Quality of Service (QoS), such as regulating traffic flows to prevent or mitigate network congestion and bottlenecks, enforcing or complying with network policies and agreements by limiting or blocking unauthorized or excessive traffic, and filtering or blocking malicious or unwanted traffic to protect the network security and stability.

6 Disadvantages of packet shaping

Packet shaping has some disadvantages for QoS, such as degrading the quality and performance of applications or users by restricting or delaying their traffic. If the packet shaping criteria or parameters are not aligned with their needs or expectations, it can interfere or conflict with other QoS techniques or mechanisms. Additionally, packet shaping can raise ethical or legal issues by affecting the network neutrality or transparency, as it may discriminate or favor certain types of traffic or users over others, violating the principles of fair access or free expression.

7 How to choose between packet scheduling and packet shaping

There is no one-size-fits-all answer to deciding between packet scheduling and packet shaping for QoS; it depends on various factors, such as the network architecture and topology, the network traffic and application characteristics, and the network objectives and constraints. However, some general guidelines can help you make an informed decision: using packet scheduling when you want to prioritize and manage traffic within your network device or segment; using packet shaping when you want to control and regulate traffic between your network device or segment and other networks or devices; and using both when you need a comprehensive QoS solution that covers both internal and external aspects of network performance.

8 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?