Citrix XenApp (formerly ICA Presentation Server) enables the processing of applications to be moved from desktop clients to centralized devices through the use of their Independent Computing Architecture (ICA).
Citrix XenApp simplifies the deployment and maintenance of applications and information to branch offices. In addition, it offers a secure way for enterprises to access key resources. In this respect, it is an important tool in the move towards branch office server centralization.
The Need for Acceleration
Citrix XenApp is an interactive application that sends screen updates and mouse movements over the WAN.As a result, it is sensitive to latency, jitter and bandwidth availability.
Most current acceleration appliances simply attempt to compress all other traffic in order to ‘make more room’ for Citrix.Many of these solutions actually hurt Citrix performance by adding additional latency.
Silver Peak - Improving Citrix Performance over the WAN
Silver Peak NX Series appliances were designed to improve the delivery of interactive applications, like Citrix XenApp. This is achieved via the following:
Avoid retransmission due to packet loss. Citrix does not perform well when packets are dropped or delivered out-of-order across the WAN. That is because packet delivery issues require retransmissions, which delay screen refreshes and make other mouse/keyboard movements appear choppy. Silver Peak addresses this problem by correcting for dropped and out-of-order packets in real-time with its Network Integrity features.
Minimize latency. NX Series appliances are finely tuned with interactive applications in mind, minimizing latency and jitter when processing Citrix traffic.
Application specific QoS. Silver Peak can properly enforce QoS to ensure that Citrix traffic is properly prioritized and has sufficient bandwidth allocated.
Data reduction. Network Memory and cross-flow compression reduce the amount of actual data that traverses the WAN. This enables Citrix to be deployed in environments that are bandwidth constrained.
Offload Citrix server.Silver Peak can perform compression on Citrix traffic, enabling this feature to be turned off in the Citrix server. As compression is processor intensive, this can dramatically improve performance within the application.
The following chart shows the Citrix performance increase that is achieved when compression is performed within the Silver Peak appliance instead of in the Citrix Presentation Server.
Printing. When a file is printed, the entire print job must be pulled across the network. Network Memory and compression reduce the amount of information traversing the WAN, cutting print time down. Future print jobs using the same document or similar revisions, will print at local printing speeds.
The net benefit is that Silver Peak improves Citrix performance across the WAN, and frees up processing power within the Citrix Presentation Server for more efficient and cost effective operations.
