Policy Routing

Policy routes provide an intelligent alternative to IP static routes. A static route's entry is limited to specifying a single gateway based on the destination address of a datagram. Policy routes can, among other things, direct traffic to different gateways based on various criteria, such as Layer 3 source or destination addresses, or Layer 4 destination ports. Policy routing is often used to provide gateway redirection services based on quality of service requirements, and for Layer 4 redirection services for use with HTTP and other application layer caching servers.

Policy routes are constructed out of two IOS elements: a route-map and one or more standard or extended IP ACLs. Route-maps behave in a manner similar to an outbound ...

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