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Chapter 4
Transparent Proxy Caching
Interception strategies
Routing solutions enable transparent interception of Internet requests. The transparency routing solutions
supported by Traffic Server are:
•
A Layer 4 switch.
See “Using a layer 4 switch with cache switching functionality to filter transparency requests” on page 23.
•
A Cisco IOS-based router using the Web Cache Control Protocol (WCCP).
See
Using a WCCP-enabled router for transparency‚ on page 24
.
•
Policy-based routing.
See
Using policy-based routing to filter transparency requests‚ on page 27
.
•
Software routing.
See
Interception bypass‚ on page 28
.
How client requests reach Traffic Server depends on network topology. In a complex network, you must
decide which clients are to be served transparently and make sure that Traffic Server is positioned to intercept
their requests. Traffic Server, or routers or switches feeding Traffic Server, are often deployed at a major artery
or aggregation pipe to the Internet.
ARM is installed by default and must be activated to use transparency. The section “ARM redirection” on
page 22 describes configuration details.
Using a layer 4 switch with cache switching functionality to filter transparency
requests
•
Layer 4 switches have the ability to rapidly redirect supported protocols to Traffic Server, while passing
all other Internet traffic through directly to its destination. Figure 4-1. below illustrates this scenario for
HTTP.
Figure 4-1. Using a Layer 4 switch to filter HTTP requests
end users
Traffic Server
Internet
L4 switch
80
all
all