Citrix SD-WAN WANOP

TCP Flow-Control acceleration

May 5, 2021

Contributed by:

S C

Ordinary WANs have very poor responsiveness at high link utilization and at long distances. A widely used rule of thumb for ordinary, non-accelerated WAN links is, “once link utilization reaches 40%, it is time to add more bandwidth, because performance and reliability have degraded to the point where the link is largely unusable.” Interactive performance suffers, making it hard for people to get work done, and connections frequently time out. Accelerated links do not have this problem. A link with 95% utilization is still perfectly usable.

Citrix SD-WAN WANOP appliances become virtual gateways that control the TCP traffic on the WAN link. Ordinary TCP is controlled on a per-connection basis by the endpoint devices. Optimal control of link traffic is difficult, because neither the endpoint devices nor individual connections have any knowledge of the link speed or the amount of competing traffic. A gateway, on the other hand, is in an ideal position to monitor and control link traffic. Ordinary gateways squander this opportunity because they cannot supply the flow control that TCP lacks. Citrix SD-WAN WANOP technology adds the intelligence that is missing in the network equipment and the TCP connections alike. The result is greatly improved WAN performance, even under harsh conditions such as high loss or extreme distance.

Citrix SD-WAN WANOP flow control is lossless and transparent, and it implements a broad spectrum of speed optimizations. No configuration is required, because of autodiscovery and autoconfiguration. You might, however, have to tweak your firewalls if they block the TCP options used by the acceleration algorithms.

The official version of this content is in English. Some of the Cloud Software Group documentation content is machine translated for your convenience only. Cloud Software Group has no control over machine-translated content, which may contain errors, inaccuracies or unsuitable language. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, suitability, or correctness of any translations made from the English original into any other language, or that your Cloud Software Group product or service conforms to any machine translated content, and any warranty provided under the applicable end user license agreement or terms of service, or any other agreement with Cloud Software Group, that the product or service conforms with any documentation shall not apply to the extent that such documentation has been machine translated. Cloud Software Group will not be held responsible for any damage or issues that may arise from using machine-translated content.

TCP Flow-Control acceleration

May 5, 2021

Contributed by:

S C

May 5, 2021

Contributed by:

S C

TCP Flow-Control acceleration

In this article