CDN: Content Delivery Networks in the Context of Security

In Information Security, we very frequently discuss the merits and challenges of Confidentiality and Integrity, but alas, Availability regularly takes the back seat...

 In today's world of Dynamic Web Content, 24/7 uptime requirements, expectations of immediately downloads, and Customers that come to you from anywhere around the world, Content Deliver Networks are fast becoming a commodity service.


 In our Enterprise Reference Architecture, we have all been taught to remove single points of failure.  A High Availability (HA) environment consists of:

• Duplicate Network Switches with redundancy protocols
• Duplicate routers with redundancy protocols
• Duplicate firewalls with Heartbeat
• Redundant ISP circuits from two different providers
• redundant power supplies in all critical infrastructure, supplied from...
• Redundant street power from two separate grids
• Cluster or HA servers for critical systems such as Corporate Websites 

These are all wonderful in a fair and decent world.... However... 

Where your Company's Image / Brand / Reputation meets your consumers, at your WebServers... there a higher level of risk, and a greater requirement for un-interrupted availability.


Enter the Content Delivery Networks (CDN)

(from http://ikuna.com)

 Content Delivery Networks provide a Geographically Disperse Web Service to replicate the content of your Web Servers, and provide that to your Customers in a highly available mode.

 

Most of the CDN providers use a subscription based approach with initial trial periods to evaluate their services.   Almost all of them provide:

• HTTP acceleration for downloading of large files and website content
• Automatic and dynamic optimization of web page content
• Intelligent routing and load balancing 
• Protection from distributed denial of service (DDoS) attacks

 Introducing a CDN service to front your Critical Corporate websites not only makes sense, but will greatly enhance your Disaster Recovery and Business Continuity programme.





Content Delivery Network Providers:  
(nowhere near a compete list, and with mergers and aquisitions... )

• Bell Canada: Content Delivery Network
• Telus Canada: Content Delivery Network (via Edgecast)
• Akamai Technologies
• Limelight Networks
• Amazon CloudFront
• AT&T's Digital Media Solutions
• BitTorrent Inc.
• CDNetworks
• Edgecast
• Ikuna
• PEER 1
• PeerCast

References:

• CDNPlanet: Content Delivery Networks
• Content delivery networks: A primer of CDN providers and technology
• Techtarget.com: content delivery network (CDN) 
• How content delivery networks (CDNs) work 
• http://www.quora.com/Content-Delivery-Networks/How-does-Akamai-CDN-work 
• http://www.searchblog.asia/topics/seo/will-using-content-delivery-networks-affect-seo/ 
• http://serverfault.com/questions/46830/how-do-cdn-content-delivery-networks-server-work 
• http://mae.ucdavis.edu/dsouza/Classes/MAE298-S09/sc421.pdf
• Updated List Of Vendors In The Content Delivery and Transparent Caching Markets 
• To Speed Up The Web, EdgeCast Has Added Google PageSpeed Technology To Its CDN