What is Open Caching?
A New Approach for Streaming:
Many Caches, All Connected
Since the beginning of streaming video, caches have been largely proprietary. Even when developed using open source technologies, like Squid, companies often made unique enhancements and developed their own approaches to hierarchies, session windows, and even the OS TCP stack. Now, with most streaming operators employing multiple CDNs, managing all of the caches across the different networks from a single interface is extremely complex. Open Caching is an attempt to level the paying field so content rights holders, network operators, and CDNs all have visibility into the caching network.
Specifications
Open Caching is defined by a library of documentation which specify the requirements, functions, and programming layer (APIs) of different elements of the Open Caching Network: Nodes, Request Routing, and Control Plane.
Code
In addition to the documentation, the Open Caching work at the Streaming Video Alliance has also produced reference code. These public repos provide a starting point for companies looking to implement Open Caching technologies.
Collaboration
The Open Caching specifications and code weren't developed by a single company. They were the result of a combined effort from dozens of companies since the Alliance's inception.
Functional Components
Click on a box to get more detail about the Open Caching component.
Enabling Caching Interoperability
Three key components make up an Open Caching Network.
Caching Nodes
An Open Caching Node represents a caching server, within a content delivery architecture, that complies with Open Caching specifications. The cache can either be built using the specifications (such as for an ISP implementing Open Caching at the edge of their network), or Open Caching functionality can be added through plugins or other means (such as for a Content Delivery Network caches or OTT Platform origins).
Request Router
The Request Router handles the inbound request for content and forwards this request to the appropriate caching node within an environment. The Open Caching specifications identify three methods of routing: DNS, HTTP, and Manifest.
Control Plane
The Control Plane handles all communication related to management of configurations, content purging and pre-positioning, logging, and security. While the Request workflow is focused on the end user’s ability to retrieve content, the Control Plane is focused on how the different members of the video distribution chain are empowered to partake in the delivery process.
The Industry is Beginning to Notice
Open Caching Implementations
Document Spotlight
SVTA5010: Geo-Data for IPv6
There are many different approaches to associating attributes to an IP address and many different attributes that can apply. There are also several different approaches to delivering that data. This document will focus on attributes that fall into three categories: Identity, Service, and Location. Identity can include a user’s name, the upstream service provider, an enterprise network, university, or department. Services can include attributes such as a W-Fi network, cable, wireless, infrastructure, and enterprise. Finally, location attributes can identify city, state, zip codes, country, region, or geocodes. A collection of attributes would form objects with their associated values, and these objects can be related to an individual IP address or a range of addresses to create an IP addressing object. These IP address objects can also be tied to an IP address object in a parent child relationship to provide as much detail as desired by the source. This document provides a JSON object model and schema to represent how those attributes can be tied to an IP address in a common format for controlling the access to streaming video using geo-location data for IPv4 and IPv6 addressing.
Note: access controls, privacy, and the management of privileged information (PII) will not be defined here and will be left to other efforts.
