Having previously used commercial content delivery networks to get their streaming video to their customers (and accounting for about 30% of all Internet Service Provider peak traffic in the US) Netflix is taking the step of deploying its own Netflix Open Connect CDN with custom hardware deployed to ISPs who merit the need to have cached copies of the Netflix content at their datacenters.

The Netflix Open Connect appliance is a rack mounted directed cache appliance that contains as much as 100 TB of Netflix content, limiting the need for the ISP to route traffic elsewhere on the Internet to service their customers Netflix streaming needs. The appliance (or multiple appliances, depending upon Netflix's assessment of the needs of the ISP) handles the traffic that is directed directly at the Netflix service; it is otherwise blind to the traffic at the ISP.  The ISP controls the network for sources of data for the appliance (updates and cache content) and for the client network access to the device, but otherwise is not responsible for the appliance once installed. Monitoring, maintenance, repair and replacement are handled by Netflix.

First deployed at the end of 2011, the appliance is a 4U standard rack sized device that contains 100 TB of disk storage and 10 GbE connectivity.  A custom chassis from TST Corp, and assembly and design by systems integrator Intequus completes the package which is otherwise built from over the counter hardware:

Description	Vendor & Model	Quantity
Chassis	TST custom	1
Motherboard	Supermicro X9SCM-F	1
Processor	Intel E3-1260L	1
Memory	8GB ECC 1333MHz	4
Hard Drive	Hitachi Deskstar 5K3000 3TB	36
Hard Drive (alternate)	Seagate Barracuda 7200.14 3TB	36
Controller	LSI SAS 92016-16i 16 port	2
Network card	Supermicro AOC-STGN-i2S	1
Redundant Power Supply Unit (AC/DC options)	Zippy MRW-5600V4V/DMRW-5600V4V	1
Misc.	2U active CPU Heatsink, SATA Cables, NIC optics

The operating system on the appliance is FreeBSD 9.0, the web server is nginx, both selected by Netflix for their proven scalability in the Netflix environment. Video and audio is served via HTTP in all cases. The CPU is minimally involved, as it's only task (beyond running the OS) is moving the bits from storage to the wire. This allows the use of a low-power Xeon processor (though the technology in the latest generation of Xeon CPUs may be even more applicable to this environment).

Getting control over the CDN that delivers their content to subscribers is one of the better moves that Netflix has made over the last year, and one that provides a noticeable improvement in service to their customers.

Complete details on the Netflix Open Connect Content Delivery Network can be found here.

Netflix launches content delivery network: Open Connect