Multi-tiered Proxy
Proxy servers can be chained together as illustrated in the following diagram. Multi-tiered proxy is identical to Single-tiered Proxy except that intervening proxy servers connect to other proxies rather than to an origin server.
Diagram illustrating multi-tiered proxy scenario.
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In the preceding diagram, the client uses P1 as a proxy server, and P1 uses P2 as a proxy. Depending on how they are configured, P1 and P2 can have any of the following characteristics:
P2 can forward an upstream authentication challenge from the origin server.
P1 can forward an upstream authentication challenge from P2.
P1 can propagate remote events from the client to P2.
P2 can propagate remote events from P1 to upstream servers.
P2 can proxy content from the origin server to P1.
P1 can proxy content from the P2 to the client.
P2 can redirect P1 to an alternate proxy server or origin server.
P1 can direct the client to an alternate proxy server.
P2 treats P1 as a downstream client.
P1 and P2 can cache content and stream content from a cache.
The following diagram illustrates the use of multi-tiered proxy servers in an intranet. By caching content on one or more cache proxy servers, you can reduce costs by decreasing the required bandwidth between a corporate intranet and the Internet. Also, multi-tiered proxy simplifies security administration by decreasing the number of access points to the intranet.
Illustrates multi-tiered proxy in a regionalized network.
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