Configuring web cache services using wccp, Information about wccp, Guidelines and limitations – Cisco ASA 5505 User Manual

Page 815: C h a p t e r

Advertising
background image

C H A P T E R

40-1

Cisco ASA 5500 Series Configuration Guide using the CLI

40

Configuring Web Cache Services Using WCCP

This chapter describes how to configure web caching services using WCCP, and includes the following
sections:

Information About WCCP, page 40-1

Guidelines and Limitations, page 40-1

Licensing Requirements for WCCP, page 40-2

Enabling WCCP Redirection, page 40-3

WCCP Monitoring Commands, page 40-4

Feature History for WCCP, page 40-4

Information About WCCP

The purpose of web caching is to reduce latency and network traffic. Previously-accessed web pages are
stored in a cache buffer, so if users need the page again, they can retrieve it from the cache instead of the
web server.

WCCP specifies interactions between the ASA and external web caches. The feature transparently
redirects selected types of traffic to a group of web cache engines to optimize resource usage and lower
response times. The ASA only supports WCCP Version 2.

Using an ASA as an intermediary eliminates the need for a separate router to do the WCCP redirection,
because the ASA redirects requests to cache engines. When the ASA determines that a packet needs
redirection, it skips TCP state tracking, TCP sequence number randomization, and NAT on these traffic
flows.

Guidelines and Limitations

The following WCCPv2 features are supported for the ASA:

Redirection of multiple TCP and UDP port-destined traffic.

Authentication for cache engines in a service group.

Multiple cache engines in a service group.

GRE encapsulation.

The following WCCPv2 features are not supported for the ASA:

Advertising