Instruction manual

Chapter 1: Introduction to the NetScaler 9000 Series
1-14 NetScaler 9000 Series Installation and Configuration Guide - Volume 1
NSICG60_JAN05
1.5.3.1 Compression
The NetScaler 9000 system provides transparent compression for HTML and
text files. The typical 4:1 compression yields up to 50% reduction in
bandwidth requirements out of the data center. This also results in
significantly improved end-user response time by reducing the amount of data
that must be delivered to the browser.
1.5.3.2 TCP Offload
To optimize server throughput and improve response times, the NetScaler
9000 system eliminates server-processing bottlenecks by offloading the TCP
connection burden from servers and caches and by enabling long-lived
persistent connections across the Internet. This significantly reduces the
connection burden on servers and accelerates static, dynamic and interactive
content.
1.5.3.3 Client Keep-alive
The NetScaler 9000 system further reduces WAN latency by maintaining
persistent connections with the client. Typically, a server with Keep-alive
disabled, will close a connection as soon as it has delivered an object. This
means a client must open and close many connections to download a
complete page. The NetScaler 9000 system keeps the connection open to the
client and then switches new requests onto reusable connections to the server,
thus eliminating much of the overhead and delay that the client would
experience.
When the server closes the connection, the NetScaler 9000 system keeps the
client-side connection (between the client and the NetScaler 9000) open. This
allows multiple client requests to be serviced on a single client connection. In
the absence of this feature, a client would have to open a new connection for
every request to the server. Instead, client keep-alive saves packet round trips
associated with connection establishment and closure, reducing the time to
complete each transaction.
1.5.3.4 TCP Buffering
The NetScaler 9000 system also allows significant scaling of server
infrastructure and improves application response times in connection-limited,
higher packet loss situations by treating all clients as if they were connected at
LAN speeds. This is made possible by buffering data from the server onto the
NetScaler 9000 system, relieving the server from slow clients and quickly