Posts Tagged 'End User'

June 9, 2010

DNS from All Angles

Serving up content on the internet can be a tricky business. It isn’t just about running a web or app server(s) in an efficient and reliable manner. One of the other critical factors is DNS. You have to understand and optimize how the name the content is advertised under gets translated to the IP address of the content. I don’t want to turn this into a DNS primer, but the two ends of the line of communication are the authoritative DNS server controlled by the domain owner which stores the official translation of the name to the number and the resolving DNS server which acts as a cache and is where the end-user connects to directly. Both ends of the chain have their own idiosyncrasies which can affect how quickly and reliably your content gets delivered.

On the end-user side, I just read an article about how public DNS providers like OpenDNS and Google are breaking the internet. OK, maybe not breaking the internet, but the public DNS providers are confusing CDN location-based algorithms. The article is here: http://www.sajalkayan.com/in-a-cdnd-world-opendns-is-the-enemy.html and I recommend strongly that both content providers and content consumers read it.

The summary is that some CDN algorithms use the ip address (and location) of the DNS server making the request and if that DNS server is nowhere near the end-user on the internet, the end-user will get served content from farther away and will get that content slower than desired. The conclusion is that an end-user should always use a DNS server located as close as possible network-wise, usually that ends up being a DNS server of the network provider.

That is good advice for the end-user, but what about the content provider? If you flip this around and come at DNS from the content provider’s point of view who doesn’t use CDN, you want to make sure that when a DNS request is made, that your authoritative DNS server gets the ip address as fast and reliably as possible back to the end-user.

SoftLayer has built out authoritative DNS farms in all our Datacenters and Network POPs and anycasted the ip addresses for the name servers. What that means is that SoftLayer customers – who get to use our DNS for free – can have their authoritative domain services hosted at all 10 points in North America and through the routing optimization inherent in the internet, the name to number conversion for those domains will happen as close as possible to the end-user and the results will be delivered as quickly as possible.

One very important goal of every content provider is to get the end-user the best experience as possible. Understanding how the internet works from the end-user and well as the server-side is critical. It doesn’t matter how good your content or app is if the end-user has a poor experience.

-@nday91

September 15, 2009

Managing Your Traffic in the Modern Era

Over the past 10 years, I’ve run or helped run all sizes of web sites and internet applications. I’ve seen everything from single-page brochure web sites to horizontally scaled interactive portals. And what I’ve learned is that it is all about the end-user experience.

I’m not a graphics specialist or a GUI designer. I just don’t have that in my DNA. I focus more on the technical side of things working on better ways to deliver content to the user. And in the purely technical area, the best thing to do to improve the user experience is to improve the delivery speed to the user.

There are a lot of tools out there that can be used to speed up delivery. CDN, for example, is an awesome way to get static content to an end user and is very scalable. But what about scaling out the application itself?

Traditionally, a simple Layer-4 Load Balancer has been a staple component of scalable applications. This type of Load Balancing can provide capacity during traffic peaks as well as increase availability. The application runs on several servers and the load balancer uses some simple methods (least connections, round robin, etc) to distribute the load. For a lot of applications this is sufficient to get content reliably and quickly to the end user. SoftLayer offers a relatively inexpensive load-balancing service for our customers that can provide this functionality.

There is another, more sophisticated, tool that can be used to manage internet application traffic. That is the “Application Delivery Controller” (obligatory Wikipedia link: http://en.wikipedia.org/wiki/Application_Delivery_Controller) or “Load Balancer on Steroids”. This class of traffic manager can act in Layer-7, the data layer. These devices can make decisions based on the actual content of the data packets, not just the source and destination.

And an ADC can do more than load balance. It can act as a Web Application Firewall to protect your data. It can speed up your application using SSL Offloading, Content Caching, TCP Optimization, and more. This type of device is very smart and very configurable and will help in the delivering the application to the end user.

At SoftLayer we have seen our customers achieve a lot of success with our Layer-4 Load Balancer product. But we are always looking for other tools to help our customers. We always have admired the advanced functionality in the appliance-based Application Delivery Controllers on the market. Finding a way to get this enterprise-grade technology to our customers in an affordable manner was problematic. When Citrix announced that they were going to create a version of their NetScaler product that didn’t require an appliance we were thrilled. With the announcement of the NetScaler VPX we finally thought we had found the right product that we could use to affordably provision this advanced technology on-demand to our customers.

SoftLayer is VERY excited to partner with Citrix to provide the NetScaler VPX Application Delivery Controller to our customers. Our customers can order a NetScaler VPX, and in a matter of minutes be managing the delivery of their online applications using one of the most sophisticated tools on the market. Citrix does a better job of promoting the product than I do, so here is the link to their site: http://citrix.com/English/ps2/products/product.asp?contentID=21679&ntref=hp_nav_US.

Remember, it’s all about the experience of the user at the other end of the wire. Find the right tools to manage that experience and you are most of the way there. Oh yeah, and find a good graphics designer too. That helps. So does good content.

-@nday91

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