Citrix NetScaler offers a host of advanced TCP optimizations that accelerate the performance of application traffic by improving network efficiency underlying and preserving 100 percent interoperability with all clients, servers and network infrastructure. While many of these TCP optimizations have been available on NetScaler appliances for a while, what is new is the use of specific TCP profiles to Citrix XenDesktop and XenApp.
With NetScaler 10, we included a TCP profile for XenDesktop and XenApp traffic that automatically selects the relevant TCP optimizations for ICA traffic flow - with special attention given to improving the performance of the network small packets, which are common in virtualized desktop and application delivery. The predefined TCP profile for XenDesktop / XenApp sets the right parameters for best performance over any network, with a single click.
Some of these enhancements include TCP Selective Acknowledgement, TCP Window Scaling and Nagle algorithm. The net result is that by putting your front NetScaler XenDesktop or XenApp, users get a better overall experience because NetScaler optimizes TCP behaviors (eg the transmission and retransmission times maximum size). Check out this blog for more of the gory details.
NetScaler TCP optimizations extend well beyond the ICA traffic, of course. NetScaler supports many of these TCP optimization features that can be easily configured with a TCP Profile Wizard just released in NetScaler 10. Some examples include:
- selective recognition. This solves the multiple packet loss problem and the resulting reduction in flow capacity. The receivers can now inform senders of the segments and successfully received only retransmit lost packets, not whole sessions.
- Quick Ramp. If packet loss, shippers reduce their congestion window and return to throttle the data transmission. The window size can now ramp more quickly for a faster data transfer rate. Provided that the network is capable of higher rates, NetScaler increases exponentially this window to maximize quickly transfers.
- Window Scaling. This allows the TCP receive window to grow beyond 65K bytes. The overall performance of TCP is improved, especially in networks with high bandwidth and long delays. Latency is reduced and the response time is improved.
- Nagle algorithm. Many applications such as Telnet and other real-time engines give rise to very small packet sizes; often each new key race needs recognition. NetScaler supports Nagle and small packet buffers together and sends them as a group to improve the efficiency of the transmission.
The bottom line is that you do not have to be a TCP or ICA expert to squeeze the best performance for your Citrix virtual solutions.
0 Komentar