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Notes on iForum NetScaler

by Steve Richards · Published June 10, 2008 · Updated March 29, 2014

The network load balancer is going through a period of change
The concept of a load balancer is still relevant
However load balancers need to do more to earn their living, reducing cost, increasing security and optimising traffic
The load balancer of the future is best thought of as an Application Delivery Controller
Traditional role
1. better utilisation of data centre resources
2. high availability when front ending replicated application resources
3. typically passive from the perspective of the application
Why the change
1. 9 out 10 apps rolled out in 2008 are web based or have a significant web component
2. My note – compare this with the number of apps used/installed by end users – I think we will see continued high use of client apps, trivial to the enterprise but important to the user
3. often web apps are very network intensive, often 3x the bandwidth of the client server apps they replace
4. facebook alone consumed more bandwidth in 2007 than the whole of the internet in 2000
5. A 30 minute streamed video uses more bandwidth than 100 emails a day for a year
6. Users are being pulled further away to their applications
  1. globalization, flexi working, branch expansion, mobility, web 2 etc
  2. security, compliance, consolidation …
Future role
1. needs to understand applications, user usage patterns and network traffic
2. they need to optimise performance, security and cost
3. application functionality
  1. Load balancing, to minimise latency, distribute load, direct users to where capacity is available, to provide disaster recovery
  2. Content switching
  3. Attack protection, for example resisting a DOS attack, whilst still servicing real traffic
  4. Surge protection, prioritisation of traffic – for example checkout is prioritised above browsing
4. application performance
  1. enabling compression, which browsers support but many applications don’t
  2. content caching, can often increase performance by a factor of 10 or more depending on app of course
  3. TCP optimisation, buffering, keep alive
  4. performance monitoring, edge sight for netscaler
5. cost reduction
  1. TCP connection offloading
  2. SSL offloading, hardware SSL offloading reduces web server load by generally a factor of 3
  3. Content caching
  4. Example they reduced the number of web servers MSN europe had serving adverts from 80 to 8
75% of investment is focussed on network security
75% of attacks are at applications
1. Cross sight scripting, SQL injection etc
2. An application firewall is mandatory for PCI, ie credit card handling, Payment Card Handling Data Security Standard

Steve Richards

I'm retired from work as a business and IT strategist. now I'm travelling, hiking, cycling, swimming, reading, gardening, learning, writing this blog and generally enjoying good times with friends and family