Citrix Netscaler 10 Summary Notes – Day 1 and 2

Citrix Netscaler Introduction

It is an application delivery controller. It is a physical or virtual appliance that is used to control application delivery in a network.

Optimizes delivery of the following services:

• Web applications
• Cloud based services
• Virtual desktops
• Mobile services
• Business applications

What does it do:

• Accelerate application delivery up to 5 times
• Layer 4 to 7 traffic management
• Has an intergrated firewall that can be used to increase security
• Increases web server efficiency

Placement in the network:

Infront of application and database servers

What Citrix Netscaler can achieve:

• High-speed load balancing and content switching
• Application aceleration
• Data compression
• SSL acceleration
• Network optimization
• Application performance monitoring
• Application security

When Netscaler can be used (Application delivery pain points):

• To ensure application availability
• To improve performance of certain applications inorder to meet the rise in demand of the application
• When the infrastructure load is increasing and scalability turns out to be a major concern
• When there is need to adopt a multilayered security approach to protect information that traverses the network
• Scalability
• In readiness of cloud computing

Features offered by NetScaler

a) Application Availability Features:

These features ensure that the applications are always available

• Load Balancing – Traffic is managed at the request level.
• Content Switching – Can determine the which server can best respond and switches requests to it.

b) Application Visibility:

Offers application visibility and policy management

• AppExpert policy manager – For management of all application delivery capabilities. Includes AppVisualizer that provides a graphical display.
• ActionAnalytics – Intergrated real time monitoring of traffic
• AppFlow – Generate detailed application flow records
• EdgeSight – Monitors end-user experience

c) Offload Features: Increase performance demands

These features improve performance.

• SSL Offloading – Offloads SSL encryptions and decryption from the webservers hence freeing resources
• Cache redirection – Traffic is sent to reserve proxy. Non-chacheable requests are sent directly to the origin servers over persistanct connections hence reducing response delays
• TCP Buffering – Adds a speed-matching mechanism between a slow client’s network and a fast server network by buffering the response of the server before delivering it to the client at a slower speed. Retransmissions are also done by NetScaler

d) Optimization features:

Reduces load in the network.

• TCP Optimization – Some TCP tasks are moved from the servers to Netscaler hence reduced CPU load
• AppCompress – Compresses HTML and text files using GZip. Upto 50% bandwidth savings
• AppCache – On-board cache stores results of incoming requests for subsequent requests for the same information hence reducing page regeneration times.
• WAN Optimization – No reconfiguration is required in network devices when netscaler is present

Security Features:

• Content Filtering – Protects websites from malicious attacks on layer 7. Screens unwanted requests and reduces server exposure attacks
• Application Firewall – Filters traffic between servers and end users
• DNS Security Extensions – Data integrity and data origin authentication between servers and clients
• AAA Application Traffic – Verifys clients credentials and only allows approved users to access the servers
• SSL VPN – The Access Gateway can be used to deliver secure remote access for applications and virtual desktops
• SAML (Security assertion Markup Language) 2.0 – enables single sign-on

New Features in Netscaler 10

• Application delivery using load balancing and content caching
• TriScale – Improves network performance by scaling the network up for elastic performance, IN for simplicity and out for expandability. Clustering enables scaling out – Up to 32 appliances can be clustered together (both physical or virtual). The netscaler SDX appliance enables to Scale in by consolidating multiple independently managed appliances into one platform
• NextGeneration security + SSL and SSL VPNs
• Action  Analytics – Collects data info from the network
• Cloud connectivity – Can still control and secure applications even when they are in the cloud
• Application Visibility – provides end to end monitoring

Netscaler Editions:

* Standard

• Load Balancing
• Content Switching
• Rate Controls
• IPv6 Support
• Client and server Side TCP optimization
• Denial of Service
• Content Filtering
• HTTP rewrite modules

* Enterprise – Adds the following to the standard edition

• Global server Load Balancing
• Dynamic routing
• Surge protection
• Priority queuing
• Data  compression
• Citrix Command Center for simplified management of several Netscalers

* Platinum – Adds the following to the Enterprise Edition:

• Web Application firewall
• AppCache module used to accelerate applications
• EdgeSight – end to end visibility of web apps

Netscaler Installation 

Netscaler system can be installed in the following modes:

• Layer 2 Bridge
• Layer 3 Router
• Combnation of modes

Netscaler placement:

Servers -> Netscaler -> Internet -> Clients