Intel 1520 manual Static and dynamic adaptive bypass, Configuring bypass options, Source bypass

Static and dynamic rules

Static and dynamic (adaptive) bypass

Bypass rules can be either static or adaptive. Adaptive bypass rules are dynamically generated if you configure the appliance to bypass in the case of non-HTTP port 80 traffic or HTTP errors.

Static and dynamic rules look exactly the same. However, the appliance creates dynamic rules when it encounters particular problems, such as non-HTTP port 80 traffic or HTTP errors.

Hit-rate impact

Reducing hit-rate impact

Configuring bypass options

You can bypass requests based on the following criteria:

✔Requests from particular users (identified by source IP addresses); set static source bypass rules from the command-line interface

✔Requests to particular Web sites (identified by destination IP addresses); set static destination bypass rules from the command-line interface

✔Requests from specific sources to specific destinations; set static source/destination bypass rules from the command-line interface

Bypass rules fall into these categories:

Source bypass:

This rule tells the appliance to bypass a particular source IP address or range of IP addresses. For example, you can use this rule to bypass clients that want to opt out of a caching solution. Source bypass rules are not dynamically generated.

Destination bypass:

This rule tells the appliance to bypass a particular destination IP address or range of IP addresses. For example, these could be Web servers that use IP authentication based on the client’s real IP address. Destination bypass rules can be dynamically generated.

Destination bypass rules prevent the appliance from caching an entire site. You will experience hit rate impacts if the site you bypass is popular.

Source/destination pair bypass:

This rule tells the appliance to bypass requests that originate from the specified source to the specified destination. For example, you can route around specific client-server pairs that experience broken IP authentication or out-of-band HTTP traffic problems when cached.

Source/destination rules can be dynamically generated.

Source/destination bypass rules might be preferable to destination rules because they block a destination server only for those particular users that experience problems.

Appendix A Caching Solutions and Performance 127