30 Days of NetScaler: Day 3 Content Switching
NetScaler content switching
Hello, it is day 3.
A serious question.
How many different devices do you have to hand? As a guess, I expect the number is more than one. Taking that number and thinking about all the potential people that could connect to your service, that could be a lot of different devices.
What if we park the device question and instead think about the different language types? Lucky for me, a lot of people speak English. Having a way to present content that is suitable for a specific language could be a great option. However, a better option is to handle several.
Eduardo is running a series of web services for B2B commerce. The businesses that he caters to are a broad spectrum involving a mix of languages and devices.
Eduardo needs a way to handle all of these with custom content for each language.
It’s simple, he needs NetScaler.
You have requested some training; your memory might be a bit hazy as there was a football game at the weekend and the team just didn’t turn up! Who would be a football supporter? Anyway, the plan is to offer some pointers on NetScaler, with a series on all things related to the appliance. The goal is to provide you with enough information to be actually dangerous when talking to a customer or client. The number of days is a bit of an arbitrary number, but I am prepared to give you 2 minutes of material. Can I get 2 minutes of your time?
I spoke about Load balancing and GSLB in previous posts, today is all about Content Switching. CS for short. I’ll have you spouting buzzwords in no time.
Honestly, what are you talking about?
In some cases, when you want to load balance traffic, there is a need to do more than just blindly steer connections between the available web servers. Obviously, load balancing checks that web servers are in a good state. Content switching gives you the option to be a bit more specific about what gets sent where.
It’s a Super Power.
Ok, how specific can it get?
Well, you can choose between five different ways to send traffic, which gives you the flexibility in how the content is selected based on the client type, location, or other parameters.
Just to be clear, we are still doing all that LB great stuff at the same time!
So what? What problem does it solve?
Content Switching gives the admin an option to switch clients to content based on the following:
1. Language
2. Device type
3. Cookie
4. HTTP data
5. Layer3/4 data.
Who would be interested in this?
Anyone who runs a network and needs more from load balancing. It is common for NetScaler to be added for something internet-facing, as it allows the admin to be confident that she/he can have their workloads keep going as things ‘happen’.
When CS is also used, there is an option to send the clients to a specific web server in your setup for custom content.
Where does NetScaler fit in?
NetScaler is typically in front of the service that you run, here it is doing its magic in front of a web tier with CS integrated on top of the load balancing service.
In this case, NetScaler works out all the details of the individual web servers, as covered in the Load balancing walk-through earlier this week. Using CS, it can now add:
1. Which web server is needed will be based on the language requirements presented by the client browser; the diagram shows three possible language options. The NetScaler will look at the language of the browser and send the client to the corresponding web server. In this case, the languages are German, English, and Spanish. Oh la!
2. Or, instead of language, you could look at the Device type. Each device places an identifier in the HTTP header identifying its type. You could have custom content for, say, iPhone or something like Windows. Windows goes to Server 1, and iPhone goes to Server 2.
3. Or, instead of language or device type, you could switch content based on a cookie! Potentially, a cookie could be used for a loyalty program as an example, that user could then be directed to the ‘Gold+’ web server. It’s like a Willy Wonka ticket!
4. It is also possible to check the HTTP method that the client is using and say, GET’s for images go to server x, and POST requests can be pushed to another server.
5. Finally, you can check where the client Layer3/4 data is and use that to send the client request to the right server.
I’m going to the cloud, baby! We don’t need that legacy piece of equipment.
When you take a look at what a Cloud Hyperscaler offers, there are a myriad of options for load balancing. There are some that operate at Network Layer 4, there are others that work at Layer 7(the application layer). There might be others that are just Network LB, so they lack a lot of the application awareness.
In the previous section, I walked over all the options that NetScaler has to switch content and load balance at the same time. It is easy to see that it will work at all the layers.
No discrimination between ISO layers. NetScaler can cover it all, no extra $$$ either.
You decide how you want to manage your clients’ requests. NetScaler has your back.
Summary.
Content Switching is another unsung hero of businesses everywhere, and is a perfect fit for embedding smarts where you need them to get users to the right workloads.
Ultimately, it is a killer capability that is enabled with NetScaler.
What’s not to like?