It’s official!  Netscaler has emerged as the leading solution for front ending next generation Service and Content Delivery Networks (SDNs/CDNs).

With the growing number of web applications, global dispersion of application users, and the drive to centralize data centers, severe limitations of legacy layer-4 load balancers and their ability to provide the end user an overall satisfactory experience has become a significant issue.

Service and Content delivery solutions, such as Citrix Netscaler, overcome these limitations and solves the end user experience issue by providing rich traffic management capabilities that can actually speed the delivery of web applications through the use of multiple optimization and acceleration techniques.

Citrix NetScaler combines comprehensive L4-7 traffic management, application acceleration, compression, caching, and application security in a single integrated appliance. In addition to accelerating web application performance, the NetScaler enables enterprises and Government IT organizations to scale their application infrastructure to reduce operating and capital expenses.  The Netscaler provides significantly more reliable application availability to all users while reducing the number of servers required to deliver the content on the backend.

With the latest firmware release, the Citrix engineering and software development teams have combined features and functions that put Netscaler at the top of the list for best of breed solutions in the SDN/CDN market space.

Some of these features/functions include:

    AppFw auto signature download and update
    Jumbo Frames
    NetScaler SPDY Gateway
    MPTCP for Mobile
    Kerberos support for MSSQL
    Spotted VIP support for Clustering
    SAML 2 factor authentication for AAA-TM
    Advance policy expression for Diameter
    Access Gateway Plug-in for Windows-8 (32-bit & 64-bit)
    Enterprise ready Clustering Phase 2
    Rate Limiting
    Action Analytics
    IP-IP Tunneling
    Bandwidth based spillover

Transport Level Security 1.1 and 1.2 protocol support
Ability to restrict Root Certificate Authority Distinguish Name
Increased Load Balancing session limit to 10Million
Application Firewall integration with IBMTM AppScan©
Application Firewall integration with Whitehat
DataStream caching for stored procedures
HTTP Callout – IPv6 support, HTTPS support
AppTemplate enhanced for multiple endpoints
SNIP as source for AppFlow exporter
Traffic Domains – multi-tenancy within appliance
NAT46 support for IPv4 to IPv6 transition
IPv6 compliance enhancements
AutoScale enhancement with CloudPlatform
SDX Enhancements:

    Interface naming
    SNMP v3 support
    Password Management

Note: Support for Jumbo Frames is due for release by the end of 2013.

More employees than ever before are wanting access to their applications and data that will make them productive when they are outside the office. This is driving Mobility solutions to the top of the priority list for organizations enterprise wide.

Some of the specific features that Netscaler brings to the Mobility Market include support for MPTCP, TCP Westwood, and SPDY.

TCP Multipath (MPTCP)

MPTCP is a TCP/IP protocol extension that identifies and uses multiple paths available between hosts to maintain the TCP session. You have to enable MPTCP on a TCP profile and bind it to a virtual server on the Netscaler. When MPTCP is enabled, the virtual server functions as an MPTCP gateway and converts MPTCP connections with the clients to TCP connections that it maintains with the servers.
This means that if you are streaming video on your mobile device across a public wifi network and the wifi gets congested and things slow down, the Netscaler can open a connection via the wifi network and the mobile cellular network and use both connections simultaneously. The protocol puts the intelligence into the Netscaler to know that the two separate connections are actually coming from the same user.

This guarantees a higher performance connection and provides a much better end user experience, because MPTCP offers better resilience and availability than standard TCP since the application session does not fail if one link goes down.

MPTCP Use Case

TCP Westwood

The NetScaler appliance also supports TCP Westwood congestion avoidance algorithm. You can enable this algorithm by setting the Westwood option for the Flavor parameter while configuring TCP profiles on the Netscaler.
TCP Westwood (TCPW), which is a newer TCP protocol, utilizes a sender-side modification process of the window congestion control scheme. TCPW controls the window using end-to-end rate estimation in a way which is totally transparent to routers and to the destination. This makes it compatible with any network and TCP implementation. What it does is to continuously estimate, at the TCP sender, the packet rate of the connection by monitoring the ACK reception rate. The estimated connection rate is then used to compute the congestion window and slow start threshold settings after a congestion episode. Resetting the window to match available bandwidth makes TCPW more robust to sporadic losses due to wireless channel problems.


SPDY, pronounced speedy, is an open networking protocol that provides a way to more efficiently transport web content. It was primarily developed by Google. The overall goal of SPDY is to reduce web page load times. This is accomplished by using a single TCP connection per domain and utilizing compression to reduce latency. SPDY also utilizes interleaved resource requests which are then prioritized across resources.
SPDY does not replace HTTP, but it modifies the way HTTP requests and responses are sent over the network. This means that all existing server-side applications can be used without modification if a SPDY-compatible translation layer is put in place.

SPDY Performance Improvements


The Citrix NetScaler Appliance ensures the performance and availability of Web applications while optimizing network resources and securing data center assets. The NetScaler combines multiple functions in a single platform, which helps enterprises reduce network complexity and operational costs.

For additional white papers on the comparative benefits of Citrix NetScaler, click here.”