About NetCache as a Web cache

Web cache defined

Network Appliance uses the term Web cache to describe a NetCache appliance that is configured to handle any or all of the following protocols:

HTTP
NetCache supports HTTP 1.1.
HTTPS
NetCache supports HTTPS for deployments where the appliance is configured as a Web cache (forward proxy) or a Web accelerator (reverse proxy).
FTP
NetCache supports FTP over HTTP and transparent FTP. FTP over HTTP support is provided for Web browsers that request FTP URLs on the HTTP proxy port. With transparent FTP, all FTP clients, including Web browsers, can access a NetCache appliance without users needing to configure their machines to support caching service.
Gopher
NetCache supports proxying of Gopher requests, but does not support caching.
HTTP-based tunneling, for example, SNEWS and HTTPS
NetCache brings tunnels up and down, but does not analyze or cache traffic that is sent through them.
DNS for DNS caching

The following illustration shows the flow of Web requests when a Web cache is deployed. A Web cache functions as a forward proxy, acting as an agent for the browser.

Note
The term Web request in the previous illustration refers to an HTTP, FTP, Gopher, or Tunnel request. DNS requests for DNS caching would also be sent to a Web cache.

NetCache caches only cacheable objects. In response to requests for noncacheable objects (for example, CGI or private pages), NetCache fetches those objects from the Web server and passes them to the client without caching them.

Note
A Layer 7 (L7) switch can be configured to obtain noncacheable objects directly from the Web server, rather than having the Web cache fetch them and pass them to the client.

Advantages of using a Web cache

The advantages of using a NetCache appliance as a Web cache include the following:

Enables Web pages to be provided more quickly to client users because Web objects are cached close to users
Reduces network latency to enhance the overall Web experience for
e-commerce customers, intranet users, and external suppliers and partners
Reduces cost because the Internet connection is used efficiently
Duplicate requests for the same content are satisfied from the cache instead of being sent over the WAN, thus saving bandwidth costs.
Reduces bandwidth demands during network traffic surges, during which a large group of users wants access to the same small number of pages
Enables access to certain Web sites to be blocked
Some organizations block access to protect themselves from possible legal actions if employees are exposed to content that the organization considers inappropriate.
Gathers and caches network-management information that allows for more efficient network management
Off-loads work from the Web server onto the Web cache so that fewer Web servers are needed