Designing Content Networking

Content networking encompasses a selection of device types that can be deployed in a variety of ways. This section examines the following two scenarios and example designs using CN devices:

• School curriculum

• Live video and video on demand for a corporation

School Curriculum

In this first scenario, a school board wants to provide curriculum and other course information to all its students, who are distributed across a wide geographical area. The content is relatively static and therefore lends itself well to a CN solution, as shown in Figure 8-7.

Figure 8-7. Performance Can Be Improved Significantly with Content Networking

In the network in Figure 8-7, the course content resides on the curriculum server located at the school board office. A Content Distribution Manager is deployed in the same office to handle the distribution of the content to the content engines deployed in each of the schools. An optional content router (in direct mode) can also be deployed at the main office if not all schools are to be equipped with the content engines; in this case, the content router directs users' requests to the closest content engine.

The content engines in this scenario are deployed in nontransparent caching mode. Therefore, the workstations in the schools must be configured with the address of the school's content engine as their proxy address.

Live Video and Video on Demand for a Corporation

In this scenario, a corporation wants to be able to deliver live video, such as company meetings, and VoD, such as training videos, to its employees over the network. The organization uses an IP/TV broadcast server to create and send the live video and stores the VoD files on servers in its head office, as illustrated in Figure 8-8. A content switch is used in the head office to load-share among the servers.

Figure 8-8. Content Networking Ensures That Video Is Available Throughout the Enterprise

A Content Distribution Manager is also deployed in the head office to handle the distribution of the content to the content engines that are deployed in each of the branch offices. An optional content router can again be deployed at the head office if not all branch offices are to be equipped with the content engines; in this case, the content router directs users' requests to the closest content engine.

The content engines in this scenario are deployed in nontransparent caching mode. Therefore, the workstations in the branch offices must be configured with the address of the office's content engine as their proxy address.

IP multicast must be enabled on this network to ensure efficient distribution of the live video.

Note

As an alternative to implementing CN, an enterprise can contract with a provider of CDN services. A CDN service provider implements a CDN so that its clients can access CN services and features from different locations, anywhere in the world. For example, consider a company that provides e-learningthe company has course files (including, for example, videos) on its servers for customers to access worldwide. Those users closer to the servers would tend to experience faster response times than those farther away, who might experience unacceptable response times. The company can therefore contract with a CDN service provider to replicate the e-learning content on the service provider's many worldwide servers. Distant users accessing the courses are then directed to the server closest to them, drastically improving the response times they experience.