What is Traffic Shaping?

Traffic shaping, also known as packet shaping, is a type of network bandwidth management for the manipulation and prioritization of network traffic to reduce the impact of heavy use cases from effecting other users. Traffic shaping identifies and classifies traffic streams by priority. High-priority traffic is forwarded immediately, and lower-priority traffic is rate-limited using various methods.

Traffic shaping techniques are core components of most network architectures. The benefits of traffic shaping include converging network technologies into a common network architecture and guaranteeing performance requirements for critical application traffic.

Quality of Service (QoS) is a specific implementation of network traffic shaping.

Traffic Shaping as Bandwidth Management

Network bandwidth is a finite resource and had to be managed (or shaped). Traffic can be identified and allocated bandwidth using several techniques:

  • Network source or target subnets. Traffic sources often have varying business values or service level requirements.
  • By the network application level (for example by TCP/UDP service port number)
  • By the software application, often referred to as deep packet inspection (DPI)
  • By user or subscriber ID. Subscribers may have purchased various network service levels which may require higher network service levels and prioritized higher

Lower priority traffic can be rate-limited with various techniques:

  • Bandwidth throttling – reducing traffic by presenting a reduced network speed at the source
  • Packet Dropping – discarding packets when bandwidth is over-subscribed. Packet Shaping configurations will drop low-priority packets providing ample bandwidth to higher-priority traffic
  • Congestion Control – some network technologies can identify congestion situations and notify data sources to reduce the amount data transferred
  • Reroute to alternate paths – advanced network architectures often have alternate and redundant network circuits. This is common with WAN routing protocols, and LAN networks at the Layer 2 level.

Benefits of Traffic Shaping

Network Operations Automation

Traffic shaping can be managed by Traffic Management and Network Management systems centrally to maintain network reliability, availability and smooth operations. As traffic patterns and network capacity requirements change, Network Control Policies can be implemented as part of a network automation strategy.

Network Oversubscription

With the ability to combine multiple network data streams and applications onto a single network infrastructure reduces the number of redundant networks required. Dedicated networks for file storage systems and backup systems are reduced or eliminated. Network applications which massive data transfer requirements can share the same network pipes as other data and application types.

Reduced Operating Costs

Reducing the number of network infrastructures reduces the cost of procuring equipment as well as the management overhead. Each hardware and technology in an operations environment requires additional cost and efforts for technical staffs, licensing, maintenance, troubleshooting, capacity preparation and planning.

Converged Network Infrastructure

Modern trends for data center and cloud designs are converging hardware and software into simpler and unified designs. Network storage technologies like Fiber Channel and InfiniBand are moving to converged Ethernet networks. Hyper-Converged Infrastructures are further relying on converged network infrastructures. Traffic shaping is a core requirement for converged network infrastructures.

Examples of Network Priorities

Traffic can be categorized with a large number of priorities in actual practice. In this case we are describing Traffic shaping conceptually. In the following examples we have designated three priorities:

  1. High-Priority – Low-Latency with guaranteed network performance. This network traffic should perform like a dedicated network without interference from other network traffic types.
  2. Medium-Priority – Good network performance with few interruptions and dropped packets and sessions.
  3. Low-Priority – Traffic which is not sensitive to network performance and can be pushed behind other network traffic. Dropped packets or other delays are queued and continues when bandwidth is available.

The diagram depicts High-Priority traffic with a guaranteed amount of traffic. Medium-priority traffic has a dedicated portion of network bandwidth outside of what is dedicated to the High-Priority traffic. Low-Priority traffic has available what is not used by high and medium traffic classes.

Data Center LAN Networks

Data Center LAN Networks include traffic categories including:

High-Priority – Low-Latency and Guaranteed Packet Delivery

Network traffic to network storage and for database transactions require low-latency network performance with high reliability. These network applications are highly sensitive to network performance and do not tolerate dropped packets well.

  • Storage Systems
  • Database Systems

Medium-Priority – Uninterrupted traffic

User access to business applications are business critical, but do not have the performance and reliability requirements as Storage and Database systems. This class of traffic must be prioritized to provide a good user experience.

  • User access to Applications
  • IP Telephony

Low-Priority – Best effort, use bandwidth not otherwise consumed

Bulk data transfers will completely consume the bandwidth of a network. If the network bandwidth is not prioritized with Traffic Shaping technologies, critical systems suffer. This traffic class should be configured to only consume traffic unused by other traffic classes.

  • Large file copies
  • Data backups
  • Peer-to-Peer applications

Wide-Area Networks

In this example, the corporate WAN network is network branch locations connected to one or more central data centers. Since WAN networks typically do not have low-latency performance capabilities, this example shows two use cases.

Medium-Priority – Uninterrupted traffic

User access to business applications are business critical. This class of traffic must be prioritized to provide a good user experience.

  • User access to Applications
  • IP Telephony

Low-Priority – Best effort, use bandwidth not otherwise consumed

Bulk data transfers will completely consume the bandwidth of a network. If the network bandwidth is not prioritized with Traffic Shaping technologies, critical systems suffer. This traffic class should be configured to only consume traffic unused by other traffic classes.

  • Large file copies
  • File synchronization
  • Distributed File Systems

Related Terms

How A10 Can Help

The A10 Networks Thunder platform provides Application Delivery and advanced Firewall technologies which include several Traffic Shaping features such as:

  • Advanced provider Subscriber ID identification via the AAM interfaces to network management AAM systems providing network control policies. Traffic identified by subscriber can be managed through Traffic Steering and Traffic Shaping technologies.
  • Deep Packet Inspection (DPI) is core to the A10 Thunder products and is provided by the A10 Advanced Core Operating System (ACOS).
  • Over 3000 applications can be identified inside the traffic packets. Traffic can be managed based on applications and network management control policies.