Wccp-Check All Services; Wccp Interoperability With Nat; Wccp Troubleshooting Tips - Cisco ASR 1000 Series Configuration Manual
Aggregation services router ip application services cisco ios xe release 3s
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- Software configuration manual (602 pages) ,
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- Replacing (120 pages)
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Configuring WCCP
Cisco Content Engines, for example, use dynamic service 99 to specify a reverse-proxy service. However,
other content engine devices may use this service number for some other service.
WCCP—Check All Services
An interface may be configured with more than one WCCP service. When more than one WCCP service is
configured on an interface, the precedence of a service depends on the relative priority of the service compared
to the priority of the other configured services. Each WCCP service has a priority value as part of its definition.
When an interface is configured with more than one WCCP service, the precedence of the packets is matched
against service groups in priority order.
The priority of a WCCP service group cannot be configured via Cisco IOS software.
Note
With the ip wccp check services all or the ipv6 wccp check services all command, WCCP can be configured
to check all configured services for a match and perform redirection for those services if appropriate. The
caches to which packets are redirected can be controlled by a redirect ACL and by the service priority.
If no WCCP services are configured with a redirect ACL, the services are considered in priority order until a
service is found that matches the IP packet. If no services match the packet, the packet is not redirected. If a
service matches the packet and the service has a redirect ACL configured, then the IP packet will be checked
against the ACL. If the packet is rejected by the ACL, the packet will not be passed down to lower priority
services unless the ip wccp check services all or the ipv6 wccp check services all command is configured.
When the ip wccp check services all or the ipv6 wccp check services all command is configured, WCCP
will continue to attempt to match the packet against any remaining lower priority services configured on the
interface.
WCCP Interoperability with NAT
To redirect traffic using WCCP to a router running WAAS software that is also configured with NAT, enable
the ip nat inside or the ipv6 nat inside command on the WAAS interface. If you are not able to configure
the ip nat inside or theipv6 nat inside command on the WAAS interface, disable Cisco Express Forwarding.
You must also update the WCCP redirect ACL to include a private address to ensure that pretranslated traffic
is redirected.
WCCP Troubleshooting Tips
CPU usage may be very high when WCCP is enabled. The WCCP counters enable a determination of the
bypass traffic directly on the router and can indicate whether the cause is high CPU usage due to enablement
of WCCP. In some situations, 10 percent bypass traffic may be normal; in other situations, 10 percent may
be high. However, any figure above 25 percent should prompt a closer investigation of what is occurring in
the web cache.
If the counters suggest that the level of bypass traffic is high, the next step is to examine the bypass counters
in the content engine and determine why the content engine is choosing to bypass the traffic. You can log in
to the content engine console and use the CLI to investigate further. The counters allow you to determine the
percent of traffic being bypassed.
IP Application Services Configuration Guide, Cisco IOS XE Release 3S (Cisco ASR 1000)
WCCP—Check All Services
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