Distributed cache mode example

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Updated: November 4, 2009

Applies To: Windows Server 2008 R2

In this example, BranchCache is deployed in distributed cache mode at a main office and a single branch office. This example depicts the following two stage process:

  • The branch office client computer Client 1 seeks and obtains content from the main office content server.

  • Another client computer in the same branch office, Client 2, seeks the same content that was originally obtained by Client 1. In this case, Client 2 obtains the content from Client 1 instead of over the wide area network link from the main office content server.

At the outset of the process, the employee using the computer Client 1 attempts to access content that is stored on a BranchCache-enabled content server.

Note

The content that the employee wants to access can be on any of the three types of content servers – a Web server, a BITS-based application server, or a file server.

In the following illustration, Client 1 seeks and obtains content from the main office content server.

 

The numbers in the illustration above correspond to the following actions:

  1. Client 1 sends a request for content to the main office content server. In this request, Client 1 indicates that it is BranchCache-capable.

  2. The content server obtains previously generated content information from a local cache and sends it to Client 1.

  3. Client 1 uses the content information and sends a multicast message to all computers on the subnet requesting the content; no computers have the content, however, because none of them has previously downloaded the content from the main office.

  4. Client 1 requests the content from the main office content server.

  5. Client 1 receives content from the content server and stores the content in its cache.

In the following illustration, Client 2 seeks and obtains content from Client 1.

The numbers in the illustration above correspond to the following actions:

  1. Client 2 sends a request for content to the main office content server. In this case, Client 2 seeks the same content that Client 1 has already obtained.

  2. The content server obtains previously generated content information from a local cache and sends it to Client 2.

  3. Client 2 uses the content information and sends a multicast message to determine if any clients in the branch office have already cached the content. Client 1 sends a response stating that it has the content.

  4. Client 2 requests the content from Client 1, connects to Client 1, and downloads the content.