Jun 10 2008
Notes on iForum NetScaler
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
- better utilisation of data centre resources
- high availability when front ending replicated application resources
- typically passive from the perspective of the application
- Why the change
- 9 out 10 apps rolled out in 2008 are web based or have a significant web component
- 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
- often web apps are very network intensive, often 3x the bandwidth of the client server apps they replace
- facebook alone consumed more bandwidth in 2007 than the whole of the internet in 2000
- A 30 minute streamed video uses more bandwidth than 100 emails a day for a year
- Users are being pulled further away to their applications
- globalization, flexi working, branch expansion, mobility, web 2 etc
- security, compliance, consolidation …
- Future role
- needs to understand applications, user usage patterns and network traffic
- they need to optimise performance, security and cost
- application functionality
- Load balancing, to minimise latency, distribute load, direct users to where capacity is available, to provide disaster recovery
- Content switching
- Attack protection, for example resisting a DOS attack, whilst still servicing real traffic
- Surge protection, prioritisation of traffic – for example checkout is prioritised above browsing
- application performance
- enabling compression, which browsers support but many applications don’t
- content caching, can often increase performance by a factor of 10 or more depending on app of course
- TCP optimisation, buffering, keep alive
- performance monitoring, edge sight for netscaler
- cost reduction
- TCP connection offloading
- SSL offloading, hardware SSL offloading reduces web server load by generally a factor of 3
- Content caching
- 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
- Cross sight scripting, SQL injection etc
- An application firewall is mandatory for PCI, ie credit card handling, Payment Card Handling Data Security Standard
