Troubleshooting guide

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Cisco Wide Area Application Services Configuration Guide
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Chapter 1 Planning Your WAAS Network
Supported Methods of Traffic Redirection
router stops redirecting packets to the WAE. When you use WCCP Version 2, the branch WAE is not
made a single point of failure for the WAAS services. The router or ANC can also load balance the traffic
among a number of branch WAEs.
You can use CLI commands to configure basic WCCP on both the routers and the WAEs, or you can use
CLI commands to configure the router for WCCP and use the WAAS Central Manager GUI to configure
basic WCCP on the WAEs.
We recommend that you use the WAAS CLI to complete the initial basic configuration of WCCP on your
first branch WAE and data center WAE, as described in the Cisco Wide Area Application Services Quick
Configuration Guide. After you have verified that WCCP transparent redirection is working properly,
you can use the WAAS Central Manager GUI to centrally modify this basic WCCP configuration or
configure additional WCCP settings (for example, load balancing) for a WAE (or group of WAEs). For
more information, see the “Configuring WCCP on WAEs” section on page 1-11. After you have
configured basic WCCP on the router, you can configure advanced WCCP features on the router, as
described in the “Configuring Advanced WCCP Features on Routers” section on page 1-6.
Advantages and Disadvantages of Using PBR
PBR allows IT organizations to configure their network devices (a router or a Layer 4 to Layer 6 switch)
to selectively route traffic to the next hop based on the classification of the traffic. WAAS administrators
can use PBR to transparently integrate a WAE into their existing branch office network and data centers.
PBR can be used to establish a route that goes through a WAE for some or all packets, based on the
defined policies.
To configure PBR, you must create a route map and then apply the route map to the router interface on
which you want the transparent traffic redirection to occur. Route maps reference access lists that contain
explicit permit or deny criteria. The access lists define the traffic that is “interesting” to the WAE (that
is, traffic that the network device should transparently intercept and redirect to the local WAE). Route
maps define how the network device should handle “interesting” traffic (for example, send the packet to
the next hop, which is the local WAE).
The following list summarizes the main advantages of using PBR instead of WCCP Version 2 to
transparently redirect IP/TCP traffic to a WAE:
• PBR provides higher performance than WCCP Version 2 because there is no GRE overhead.
• By default PBR uses CEF when CEF is enabled on the router (PBR using CEF for fast switching of
packets).
• PBR can be implemented on any Cisco IOS-capable router or switch that is running an appropriate
version of the Cisco IOS software. We recommend that you use Cisco IOS Software Release 12.2
or later.
• PBR provides failover if multiple next-hop addresses are defined.
The following list summarizes the main disadvantages of using PBR instead of WCCP Version 2 to
transparently redirect IP/TCP traffic to a WAE:
• PBR does not support load balancing between equal cost routes. Consequently, PBR does not
provide scalability for the deployment location.
• PBR is more difficult to configure than WCCP Version 2. For an example of how to configure PBR
for WAAS traffic, see the “Using Policy-Based Routing Interception” section on page 1-33.