F5 Networks Big-IP 6400

Virtual servers come next where you provide an IP address, decide on the type of service on offer and assign a pool to them. The HTTP profile brings in valuable traffic optimisation and acceleration capabilities, which will be very useful for slow WAN links. Along with compression, the appliance can also cache HTTP objects in memory to improve web server responses.

Layer 4 inspection can maintain persistent connections where the appliance uses source and destination IP addresses or SSL session IDs to ensure a specific client is always directed to the same server. Layer 7 inspection takes this up a level as you can use actual content to set up persistent connections along with features including application session IDs, URLs and cookies.

Universal persistence maintains a state table using any information gathered from Layer 4 through to Layer 7 inspection and employs this to maintain persistent connections. Of course, cookie based persistence is on the list and is a technology that F5 actually pioneered a number of years ago.

F5's iRules enble you to create custom policies that determine how specific traffic is handled. These can range from looking for information such as credit cards numbers in HTTP traffic and replacing them with hashes to identifying VoIP traffic, prioritising it and maybe modifying the packet contents.

Other functions could be to inspect HTTP content and based on information such as the URI, cookie or HTTP response codes, direct a host to a particular physical server. After some practise we found iRules easy enough to use and for testing we created one that inspected HTTP web mail traffic for details of our mail server software. When activated our rule simply removed the name of the software as returned allowing us to hide this information.

The web interface provides reasonably good real time statistics on appliance performance, traffic handling and load balancing but general reporting tools are thin on the ground. At present this requires integration with third party management tools such as HP OpenView. However, F5 advised it is working on an optional appliance reporting tool based on Microsoft's System Center Operations Manager.

Considering the starting price we would have expected a superior hardware specification but there's no denying the Big-IP 6400 is delivering an impressive range of load balancing and application delivery features. Reporting options are also limited but the management interface is easy to get on with making the system very simple to deploy.