Video caching 编辑

How is video caching different from Disk Based Compression?

With caching, a local copy of the cached object is served by the local appliance, without downloading it again from the remote server. Caching does not require an appliance on both ends of the link, just on the local end. With compression, a remote copy of the object is served by the remote server. The remote (server-side) appliance compresses it, reducing its size, and therefore, increasing its transmission speed, and the local (client-side) appliance decompresses it.

Compression works on both modified and unmodified objects. If a file changes by 1% on the server, the next transfer achieves up to 99:1 compression.

Caching works only on unmodified objects. If a file changes by 1% on the server, the new version must be downloaded in its entirety. Caching and compression are complementary technologies, because anything that is not cached, is compressed, achieving the benefits of both.

Can I partition the appliance’s total memory between the video cache and other Citrix SD-WAN WANOP features?

No. Cache partition and memory required are not configurable.

What are the supported video container formats?

Video caching is independent of codec format and supports all major container formats.

Can I activate caching for internal and external enterprise videos on my own sites?

Yes. If access to these videos is through HTTP, you can configure these sites for caching.

Can I configure the maximum size for a cached object?

Yes. An object larger than the limit that you configure is not be cached. To set this limit, navigate to Configuration > Optimization Rules > Video Caching and select the value from the available limits.

How does video caching improve the user experience?

Caching improves the user experience for videos that are viewed more than once, especially on slower links. The first viewer of a given video stream does not benefit from the video caching feature, but subsequent views are delivered at the LAN speed from the Citrix SD-WAN WANOP appliance, with the additional benefit of reduced WAN usage.

In addition, if a second user requests the same video while it is still being streamed for the first user, the second user will receive the cached copy.

Unlike normal Citrix SD-WAN WANOP TCP operation, where the appliance preserves the original source and destination IP addresses, the appliance replaces the client’s source address with IP address assigned to the accelerated bridge, so all HTTP traffic passing through the appliance appears to originate from the appliance itself.

Which Citrix SD-WAN WANOP appliances support Video Caching?

The following appliances support the video caching feature:

• SD-WAN WANOP 800 appliance with all bandwidth license models.

• SD-WAN WANOP 1000 appliance with Windows Server, with all bandwidth license models.

• SD-WAN WANOP 2000 appliance with all the bandwidth license models.

• SD-WAN WANOP 2000 appliance with Windows Server, with all bandwidth license models.

• SD-WAN WANOP 3000 appliance with all the bandwidth license models.

For video caching, which deployment modes are the supported on a Citrix SD-WAN WANOP appliance?

• Supported deployment - Inline Virtual Inline, VLAN, and WCCP

• Not supported features - Citrix SD-WAN WANOP high availability, Group Modes, and Daisy Chaining

Which file extensions are supported for video caching?

The video file name must have one of the following extensions: .3gp, .avi, .dat, .divx, .dvx, .dv-avi, .flv, .fmv, .h264, .hdmov, .m15, .m1v, .m21, .m2a, .m2v, .m4e .m4v, .m75, .moov, .mov, .movie, .mp21, mp2v, .mp4, .mp4v, .mpe, .mpeg, mpeg4, mpg, mpg2, .mpv, .mts, .ogg, .ogv, .qt, .qtm, .ra, .rm, .ram, .rmd, .rms, rmvb, .rp, rv, .swf, .ts, .vfw, .vob, .webm, .wm, .wma, .wmv, and .wtv.

Can I enable the video caching feature on an unsupported Citrix SD-WAN WANOP platform?

No. The Video Caching feature cannot be used on unsupported platforms.

What are the minimum configuration and other prerequisites for enabling the video caching feature?

To enable the video caching feature, you must:

• Assign a valid IP address and gateway to the apA interface and, if present, to the apB interface.

• On the appliance, configure a valid DNS server that can resolve to www.citrix.com.

• Have at least one application in the Selected Video Caching Applications list.

• Check the Citrix SD-WAN WANOP GUI alerts/notification of existing configuration alerts.

Can the Citrix SD-WAN WANOP plug-in use the Video Caching feature?

No. You cannot use the Video Caching feature with Citrix SD-WAN WANOP plug-in.

What are the supported browsers and devices?

Video caching supports the Internet Explorer, Firefox, and Chrome browsers. Videos can be viewed on Windows 7 or 8, Apple iPad, and Android iOS devices.

Does the Citrix SD-WAN WANOP appliance support video caching for all video websites?

No. The video website is available and added from the Supported Application list on the Video Caching configuration page. By default the supported applications include YouTube, Vimeo, Youku, Dailymotion and Metacafe. You can add other websites by specifying their IP addresses, if they do not use caching avoidance mechanisms, such as adding random characters to URLs.

Is the SNMP monitoring supported for video caching?

Yes. You can use SNMP MIBs to monitor video caching specific tasks.

Is video caching supported for non-HTTP traffic?

No. Video Caching is not supported for non-HTTP traffic, such as HTTPs, RTSP, and RTMP.

Can I use video caching with HTTP traffic sent to a port other than port 80?

Yes. For video caching, you can add customized ports to the appliance. To add customized ports for video caching, navigate to the Configuration > Optimization Rules > Video Caching page and click the Global Settings link on the Settings tab.

Can Citrix SD-WAN WANOP compression (using an HTTP Service Class policy) be used with Video Caching?

Yes. When the cached objects are present in both Citrix SD-WAN WANOP compression history and the video cache, the content is served from the cache on a cache hit, and fetched from the server (and compressed) on a cache miss.

Does an existing HTTP Application which requires IP address configuration when there is a transparent proxy, require any changes?

Yes. Citrix SD-WAN WANOP performs HTTP transparent proxying, in which it replaces the Source IP address of the packet. Therefore, if the existing HTTP application has certain policies (such as to block certain IP addresses or Proxy mechanisms), those policies have to be changed.

What are the system memory and connection limits for the HTTP proxy connection?

To determine the limits, check the graphs and statistics on the Video Caching Debug page (support.html). Additionally, verify that the Videocaching.cmd stats info command shows the following information.

After the above HTTP connection limits are reached,new connections are bypassed.

Note

Make sure that you do not change the above configuration.

Does the Monitoring page for video caching include only video traffic?

Yes. Non-video HTTP traffic (even though it is intercepted by the proxy), is not included in the video caching GUI statistics.

Do I need to configure apA as well as apB interfaces with a valid IP address on a Citrix SD-WAN WANOP appliance?

No. You do not need to assign a valid IP address to both the interfaces. HTTP packets received from the apA interface are proxied with the apA IP address, and HTTP packets received from the apB interface are proxied with the apB IP address.

If you do not configure an IP address for an interface, the HTTP packets received on that interface do not get the caching benefit.

What is the minimum and maximum limit for the size of a video file that can be cached?

• Minimum: 100 KB

• Maximum: 300 MB

• Default: 100 MB

How is the video caching disk cleared?

Cached objects are cleared as specified by the Least Recently Used algorithm.

What happens when I upgrade the Citrix SD-WAN WANOP appliance from release 6.x to 7.y and video caching is enabled?

The existing Citrix SD-WAN WANOP DBC history is lost and a separate partition for video caching is created.

What happens when I downgrade the Citrix SD-WAN WANOP appliance from release 7.y to 6.x and video caching is enabled?

Citrix SD-WAN WANOP DBC and Video Caching history is preserved. However, the video caching feature is not available with release 6.x.

What happens when I upgrade the Citrix SD-WAN WANOP appliance from release 7.x to 7.y and video caching is enabled?

The Citrix SD-WAN WANOP DBC and video caching history is preserved.

I have a single network in branch office that shares a management as well as data traffic. How should I configure video caching in this network?

If you have single network for management and data traffic, Citrix recommends that you add the primary IP address to the LAN side of the accelerated bridge port.

What is the maximum number of prepopulation tasks I can run at the same time?

One. If you attempt to start multiple prepopulation tasks at the same time, the appliance builds a queue of tasks on a first in first out basis.

What is the maximum number of videos sources I can configure on the appliance?

100

What is the maximum number of prepopulation entries I can add to the appliance?

50

What is the maximum number of video files be downloaded and cached from a directory listed folder?

300

Does the video downloading and caching initiated by the prepopulation feature get the disk based compression (DBC) benefits?

Yes. Because the video file is cached, the attempt to access the video is served from the cache.