As the distance between locations increases over the WAN, especially for remote international sites with low-speed transport services, or where there are long backhauls, application performance degrades. This has less to do with the available bandwidth and more to do with the time it takes to send and receive data packets over distance, 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.
To counter such challenges, enterprises deploy WAN optimisation solutions. A common misconception persists that SD-WAN reduces or eliminates the need for WAN optimisation techniques. The reality is that SD-WAN and WAN optimisation solve fundamentally different problems, and they are complementary when deployed in unison.
Geographically distributed enterprises with locations worldwide can experience impaired application performance for critical, latency-sensitive TCP/IP applications such as transaction processing or data backup caused by excessive roundtrip delays. Network latency is primarily caused by geographical distance between sites, and additional bandwidth does not change the laws of physics.
According to Warren Gordon, ARUBA/HPE Business Unit Manager at Duxbury Networking (local distributor of ARUBA/HPE technology): “Geographically spread out companies face a common problem: their computer systems slow down when they try to work together from different locations worldwide. This happens because the data takes a longer time to travel over long distances, leading to delays and sometimes even losing some data along the way. To solve this issue, businesses use two helpful tools. Firstly, SD-WAN helps them connect their systems securely and quickly. Secondly, WAN optimisation ensures that their applications work faster and more efficiently.
“Duxbury understands these challenges. That’s why we offer an SD-WAN solution that not only ensures a smooth connection, but also works hand-in-hand with WAN optimisation to ensure everything runs seamlessly, no matter where you are in the world. With this solution, our customers can enjoy better performance and smoother operations across their company's locations.”
By deploying a virtual instance of Aruba EdgeConnect Enterprise SD-WAN appliance in the public cloud, and enabling Aruba WAN Boost optimisation, enterprises can overcome application and network latency performance problems and accelerate cloud-hosted applications and data transmission to the cloud from anywhere.
As enterprises migrate more and more in-house applications to public cloud environments, they need to address the network latency limitations encountered while connecting to IaaS workloads. In cloud environments, the physical location of the company’s server and the IP address or subnet might change at any time.
With Aruba WAN Boost, enabled on a virtual instance of the Aruba EdgeConnect Enterprise SD-WAN edge platform, enterprises can leverage the WAN optimisation techniques to ensure seamless public cloud integration, even if the server IP address or subnets change, allowing enterprises to take full advantage of the flexibility of the cloud, without any concern for application performance.
Aruba WAN Boost accelerates data movement between data centres, branch offices and the cloud. It uses real-time optimisation techniques to overcome network quality, capacity and distance challenges, resulting in fast and reliable access to information, anywhere in the world. Aruba WAN Boost key WAN optimisation features include:
- Latency mitigation via TCP protocol acceleration techniques that improve application response times over distance.
- Data reduction techniques that include compression and data deduplication mechanisms to reduce the amount of data that traverses over WAN links.
TCP Protocol acceleration can improve the performance of latency-sensitive applications, and data reduction techniques provide benefits when transferring large data sets, especially between geographically distributed locations.
Aruba WAN Boost is integrated with Aruba EdgeConnect Enterprise and is not a separate VNF for the sole purpose of supporting WAN optimisation. The flexible Aruba WAN Boost consumption model provides WAN optimisation for applications where and when it is needed.
Aruba WAN Boost is enabled in the business intent overlay configuration for classes of critical applications that benefit from it, and it is usually not enabled for applications that do not require WAN optimisation such as less latency-sensitive or real-time applications like voice and video conferencing.
TCP protocol acceleration techniques
TCP is a connection-oriented and rate-limiting protocol, which is widely used in data networking and on the internet (for example, HTTP, HTTPS, SCP/FTP and SMTP) and plays an integral role in determining overall network performance.
TCP maintains a window that dictates how much traffic can flow over a connection. The TCP window is the amount of data a sender can send on a path before an acknowledgment is sent back from the receiver. TCP starts with a small window size and gradually increases the window size until an acknowledgment isn’t received within a specified time period. When this occurs, TCP assumes network congestion and packet loss. The protocol responds by re-transmitting the lost data packet and decreasing the window size.
Typically, TCP has a 16-bit window field that is used by the receiver to inform to the sender how many bytes of data the receiver is willing to accept. In standard TCP implementation, the window field is limited to 16 bits, supporting a maximum window size of 65 535 bytes.
Aruba WAN Boost WAN optimisation software supports a window scaling feature that delivers window sizes as large as 1GB, overcoming the throughput limitation imposed by the standard 64KB TCP window size. This allows users to send more data per flow, making most of the available bandwidth.
Roundtrip time (RTT) is the duration in milliseconds (ms) it takes for a data packet to go from a starting point to a destination and back again to the starting point. Aruba Boost employs a round-trip measurement scheme that enables more efficient RTT calculation for more accurate RTO (retransmission timeout) measurements to improve network throughput.
The TCP acknowledgment system can’t handle multiple lost segments; it only acknowledges the last successfully received segment leading to the retransmission of data that was already received by the receiver. To counter this, Aruba WAN Boost supports a selective acknowledgment (SACK) mechanism in which only the necessary packets, which never reached the receiver, are resent. This drastically improves network performance as fewer packets are retransmitted, and results in efficient use of bandwidth.
Aruba WAN Boost offers high-speed TCP, a modification to the standard TCP congestion control technique. In high-speed TCP, the TCP congestion control alters how the congestion window, which regulates the times at which the segments are sent into the network, is opened on each roundtrip and closed on congestion events for better performance in high-bandwidth, high-latency environments.
Aruba WAN Boost optimisation delivers the technology needed to improve WAN performance and offers end-users a LAN-like experience. Data reduction techniques allow enterprises to achieve superior application performance over a hybrid WAN comprising MPLS, internet and 4G/5G/LTE connections. The data reduction techniques include data compression and deduplication that eliminate the transmission of any redundant data, thereby improving WAN performance.
The WAN is no longer just a pipe that connects point A to point B; it has become a strategic asset that enables employees to be more productive, businesses to be more competitive, respond more quickly to customer and industry demands, and serve as a foundation for whatever innovations might evolve next. The challenge of delivering applications to users at branch offices and data centre sites with high performance has not gone away. The rise of cloud networking, SaaS applications and IaaS workloads has made the issue more complicated. Aruba EdgeConnect Enterprise with Aruba WAN Boost can improve the connectivity to cloud-based applications, accelerate performance and optimise bandwidth utilisation between branch offices, enterprise data centres and public cloud environments.
“We work closely with our customers to understand their specific needs and challenges. Aruba EdgeConnect is our top recommendation for SD-WAN because it effectively addresses the performance issues of geographically distributed enterprises. Its application-driven approach prioritises critical applications, while WAN optimisation further enhances network efficiency, resulting in improved performance and productivity across the entire network,” says Gordon.
For more information, contact Duxbury Networking, (+27) 011 351 9800, info@duxnet.co.za, www.duxbury.co.za.
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Duxbury Networking
Since its formation in 1984 by CEO, Graham Duxbury, Duxbury Networking has embraced ongoing technological changes within the ICT sector in order to provide its customers with access to the latest trends and solutions. Satisfying the evolving and diverse needs of its customer base is achieved through an emphasis on sourcing cost-effective, high-quality products from carefully selected local and international vendors. Aligned with this is the provision of uncompromising technical support, which is possible due to an extensive investment in the training and upskilling of its team. The company is driven to take an active role in reshaping and redefining the South African digital landscape in its mission to help its customers build a network that will support current and future technologies.