What is WAN Optimization?

WAN optimization uses a set of techniques to boost performance and data transfer in Wide Area Networks (WANs) to overcome the adverse effects of latency, bandwidth limitations, and packet loss. These techniques rely on TCP acceleration, data compression, data deduplication, and forward error correction.

WAN optimization explained

As the geographical distance between locations increases over the WAN, especially for remote international sites with low-speed transport services or long backhauls, the performance of applications tends to degrade. This degradation is not solely dependent on available bandwidth but is primarily influenced by factors such as the time required for data packets to travel back and forth over the WAN, the need for data receipt acknowledgements required by some protocols before sending the next segment of data, and the number of times data must be retransmitted due to packet loss.

Geographically distributed enterprises with worldwide locations may face compromised application performance, especially for critical, latency-sensitive TCP/IP applications such as transaction processing or data backup caused by excessive round-trip delays. It’s important to note that additional bandwidth alone does not represent a practical solution as network latency is primarily caused by the geographical distance between sites. To counter such challenges, enterprises deploy WAN optimization solutions.

How does WAN optimization work?

The primary objective of WAN optimization is to overcome the inherent limitations of wide area networks (WANs), such as high latency, limited bandwidth, and potential packet loss.

TCP Protocol Acceleration mitigates the effects of latency to improve application response times over distance. TCP Acceleration overcomes delays with four key components:

  • Window scaling increases the transmitting window size, allowing more data to be sent before an acknowledgement is received.
  • Selective acknowledgement (SACK) allows retransmitting only necessary packets in lossy network environments, avoiding redundant retransmission.
  • Round trip time measurement reduces the round-trip time (RTT) measurement by utilizing actual latency instead of the fixed-length acknowledgement timer normally used for lost packets.
  • High-speed TCP enhances the congestion control mechanism by optimizing the congestion window size that regulates the times at which segments are sent into the network. In standard TCP congestion control, it may take a very long time for the congestion window to recover. With high-speed TCP, the window congestion size increases by a larger amount and decreases by a smaller amount.

WAN optimization TCP protocol
TCP protocol acceleration techniques accelerate applications over distance overcoming the effects of latency

Data Reduction eliminates the overhead of redundant packets traversing the WAN using:

  • Data deduplication which removes duplicate data and replaces it with a fingerprint and a pointer so that only the necessary data is transmitted across the WAN. The original data is stored in a disk cache so that data is reconstructed with the duplicate data at the destination.
  • Data compression leverages compression algorithms such as LZ (Lempel-Ziv) compression to reduce the amount of data transmitted. Data compression is applied both for the payload and the IP header.

Data deduplication eliminates overhead of redundant packets traversing the WAN
Data deduplication eliminates overhead of redundant packets traversing the WAN

Path Conditioning mitigates the effects of Internet and wireless links that often suffer from packet loss and jitter and are more prone to outages with:

  • Forward Error Correction (FEC): Lost packets in transmit are automatically rebuilt by periodically sending parity packets over the network, allowing the receiver to correct errors without requesting retransmission, ensuring data integrity, and reducing the impact of packet loss. The FEC ratio can be configured depending on Quality of Experience requirements—ranging from 1:1 for real-time voice or video applications to an adaptive algorithm that automatically adjusts error correction based on packet loss.
  • Packet Order Correction (POC): When load-balancing traffic between multiple WAN transport links, POC re-orders any packets that arrive out of sequence at the destination..

Why should I consider WAN optimization?

  • Support geographically distributed organizations
    In distributed organizations, many branch offices are in remote areas where consistent high-speed internet connectivity is an issue. Because of this, the sharing of business information among enterprise systems is slow, which affects the speed of business. With an integrated WAN optimization solution, enterprises can confidently maintain the business agility they need to succeed in today’s competitive world.
  • Use bandwidth more efficiently
    WAN optimization helps minimize the amount of data that needs to be transmitted over the WAN, creating additional capacity for real time applications such as voice and video. It also improves the transmission of large files such as medical images or engineering design files.
  • Improve disaster recovery
    Most enterprise disaster recovery planning includes data to be backed up in one or more remote locations that could be hundreds of miles away from the main location. As the distance between remote sites and backup locations increases, latency increases, resulting in a slower data transfer. WAN optimization improves the efficiency of data replication and backup processes, ensuring that critical data is safely transmitted and stored in remote locations.
  • Save costs
    Organizations can save costs by reducing the amount of data transmitted over the WAN using techniques such as data deduplication and compression. This allows organizations to reduce bandwidth requirements, resulting in lower expenses related to network infrastructure and WAN service providers.

What are the benefits of WAN optimization?

  • Improved application performance
    Latency in the network significantly degrades application performance. WAN optimization uses techniques that greatly improve network performance by reducing latency, minimizing data transfer durations, and optimizing bandwidth utilization. This leads to faster transfer times, improved data transfer speeds, and improved user experience. WAN optimization increases productivity as employees access critical applications more efficiently.
  • Enhanced collaboration
    WAN optimization fosters efficient collaboration among teams spread across geographically distributed locations. By reducing latency and optimizing data transfer, it enables real-time communication, seamless file sharing, and video conferencing. This facilitates better teamwork and productivity, benefiting employees located in remote branch offices.
  • Business continuity
    WAN optimization improves the process of backup and data replication. It ensures that data is safely transmitted and stored in remote locations. In the event of a disaster, WAN optimization provides faster data recovery, minimizing downtime and allowing organizations to quickly resume operations.

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