ApsaraVideo VOD:Configure range origin fetch

Background information

Range origin fetch allows an origin server to return only a specified part of a file to a client. This feature improves the delivery of large files, such as audio and video files.

Procedure

1. Log on to the ApsaraVideo VOD console.

2. In the navigation pane on the left, under Configuration Management, click CDN Configuration > Domain Names.

3. Find the domain name that you want to configure and click Configure.

4. Click the Video Related tab. In the Back-to-origin of Range section, click Modify.

5. Select a setting for range origin fetch and click OK.

   

   Range origin fetch setting	Description	Example
   Enable	Enable this feature if you want to access only a specific part of a resource file. This improves response efficiency. After you enable range origin fetch, the origin server returns the byte range specified in the Range header of the request. The CDN point of presence (POP) then returns the corresponding byte range to the client.	If a client sends a request that contains range:0-100 to a CDN POP, the request forwarded to the origin server also contains range:0-100. The origin server returns the byte range from 0 to 100 (101 bytes) to the POP. The POP then returns the same byte range to the client.
   Disable	Disable this feature if you want to access the entire content of a resource file. When range origin fetch is disabled, CDN POPs request the complete file from the origin server. The HTTP connection is automatically closed after the client receives the byte range specified in its request. As a result, the complete file is not cached on the POP. This decreases the cache hit ratio and increases back-to-origin traffic.	If a client sends a request that contains range:0-100 to a CDN POP, the Range header is ignored in the request sent to the origin server. The origin server returns the complete file to the POP. The POP returns only the requested 101 bytes to the client. Because the connection is then closed, the complete file is not cached on the POP.
   Force	If you select Force, CDN POPs use range requests for all origin fetches, regardless of whether the client request includes a Range header. All range requests from POPs to your origin server use a chunk size of 512 KB.	Before you set Back-to-origin of Range to Force, make sure that your origin server supports the Range header. Note After you select Force, any request for a file chunk triggers a forced range origin fetch.