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This feature module describes the WCCP Redirection on Inbound Interfaces feature and includes information on the benefits of the new feature, supported platforms, configuration tasks and a command reference.
This document includes the following sections:
The WCCP Redirection on Inbound Interfaces feature adds support to Cisco IOS software for the redirection of Web Cache Communication Protocol (WCCP) traffic on inbound interfaces. Prior to this release, WCCP could be configured to redirect traffic at an outbound interface only.
This feature offers better redirection performance as well as providing more flexibility in configuring WCCP.
Inbound traffic can be configured to use Cisco Express Forwarding (CEF), Distributed Cisco Express Forwarding (dCEF), Fast Forwarding, or Process Forwarding.
This feature module documents only the enhancements added in Cisco IOS Release 12.1(3)T. For full WCCP configuration information, see the documents listed in the Related Documents section.
Better Redirection Performance
Configuring WCCP for redirection for inbound traffic on interfaces allows you to avoid the overhead associated with CEF forwarding for outbound traffic. Setting an output feature on any interface results in the slower switching path of the feature being taken by all packets arriving at all interfaces. Setting an input feature on an interface results in only those packets arriving at that interface taking the configured feature path; packets arriving at other interfaces will use the faster default path. Configuring WCCP for inbound traffic also allows packets to be classified before the routing table lookup, which translates into faster redirection of packets.
This document addresses only configuring WCCPv2 on inbound interfaces. For complete details on configuring WCCP on Cisco IOS software-based platforms, see the following documents:
For Cisco Cache Engine configuration information see:
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
RFCs
No new or modified RFCs are supported by this feature.
Before using WCCP Version 2, the following tasks must be completed:
See the following sections for configuration tasks for the WCCP Redirection on Inbound Interfaces feature:
| Command | Purpose | |
|---|---|---|
Step 1 | Router(config)# ip wccp web-cache | Enables WCCP and specifies a "web-cache" service. |
Step 2 | Router(config)# interface interface-number | Targets an interface number for which a web cache service will run. |
Step 3 | Router(config-if)# ip wccp web-cache redirect in
| Enables the check on inbound packets to determine if they qualify to be redirected. |
| Command | Purpose | |
|---|---|---|
Step 1 | Router(config)#ip wccp service-number | Enables WCCP and specifies a user-designated service (for example, Cisco Cache Engines use the value 99 to specify a Reverse-Proxy service). |
Step 2 | Router(config)# interface interface-number | Targets an interface on which the reverse proxy service will run. |
Step 3 | Router(config-if)#ip wccp service-number redirect in | Enables the check on inbound packets to determine if they qualify to be redirected. |
Use the following commands to verify and monitor the configuration settings for WCCP:
| Command | Purpose |
|---|---|
| Shows whether WCCP is configured on an interface.The output will show whether WCCP is enabled for inbound or outbound traffic, and which version of WCCP is enabled. |
Router# show ip wccp [web-cache | service-number] | Displays global information related to WCCP, including the protocol version currently running, the number of cache engines in the routers service group, which cache engine group is allowed to connect to the router, and which access list is being used. Use of the optional web-cache keyword or service-number argument will show information about the specified service. |
| Displays information on which cache engines of a specific service group the router has detected. The information can be displayed for either the web cache service or the specified dynamic service. |
Router#show ip wccp {web-cache | service-number} view
| Displays which devices in a particular service group have been detected and which cache engines are having trouble becoming visible to all other routers to which the current router is connected. The WCCP group view is the list devices which are known (can be viewed) by the routing device as part of the WCCP service group. The information can be displayed for either the web cache service or the specified dynamic service. |
The following example shows a configuration session in which redirection of HTTP traffic arriving on interface 0/1 is enabled:
Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# interface ethernet 0/1 Router(config-if)# ip wccp web-cache redirect in Router(config-if)# ^Z Router# show ip interface ethernet 0/1 . . . WCCP Redirect inbound is enabled WCCP Redirect exclude is disabled . . .
This section documents the modified command introduced by this feature. All other commands used with this feature are documented in the Release 12.1 Cisco IOS Configuration Fundamentals Command Reference.
To enable packet redirection on an outbound or inbound interface using Web Cache Communication Protocol (WCCP), use the ip wccp redirect interface configuration command. To disable WCCP redirection, use the no form of this command.
ip wccp {web-cache | service-number} redirect {out | in}
Syntax Description
web-cache Enables the web cache service. service-number The identification number of the cache engine service group being controlled by a router. The number can be from 0 to 99. If Cisco Cache Engines are used in the cache cluster, the reverse proxy service is indicated by a value of 99. redirect Enables packet redirection checking on an outbound or inbound interface. out Specifies packet redirection on an outbound interface. in Specifies packet redirection on an inbound interface.
Defaults
Redirection checking on the interface is disabled.
Command Modes
Interface configuration
Command History
12.0(3) T This command was introduced. 12.0(11)S The in keyword was added to the 12.0 S release train. 12.1(3)T The in keyword was added to the 12.1 T release train.
Release
Modification
Usage Guidelines
The ip wccp redirect in command allows you to configure WCCP redirection on an interface receiving inbound network traffic. When the command is applied to an interface, all packets arriving at that interface will be compared against the criteria defined by the specified WCCP service. If the packets match the criteria, they will be redirected.
Likewise, the ip wccp redirect out command allows you to configure the WCCP redirection check at an outbound interface.
 |
Note This command has the potential to effect the ip wccp redirect exclude in command. If you have ip wccp redirect exclude in set on an interface and you subsequently configure the ip wccp redirect in command, the "exclude in" command will be overridden. The opposite is also true: configuring the "exclude in" command will override the "redirect in" command. |
Examples
The following example shows a configuration session in which reverse proxy packets on Ethernet interface 0 are being checked for redirection and redirected to a Cisco Cache Engine:
Router# configure terminal Router(config)# ip wccp 99 Router(config)# interface ethernet 0 Router(config-if)# ip wccp 99 redirect out
The following example shows a configuration session in which HTTP traffic arriving on interface 0/1 will be redirected to a Cisco Cache Engine:
Router# configure terminal Router(config)# ip wccp web-cache Router(config)# interface ethernet 0/1
Router(config-if)# ip wccp web-cache redirect in
Related Commands
ip wccp redirect exclude in Enables redirection exclusion on an interface.
Command
Description
cache engine—A device that stores objects being downloaded from the Web for future use by the host.
Cisco Express Forwarding (CEF)—A scalable, distributed, Layer 3 switching solution designed to meet performance requirements of the Internet and enterprise networks. CEF can also refer to central CEF mode, one of the two modes of CEF operation that enables a route processor to perform express forwarding.
distributed CEF (dCEF)—One of two modes of CEF operation that enables line cards to perform the express forwarding between port adapters.
FIB—Forwarding information base
line card—A general term for an interface processor that can be used in a line of Cisco products. For example, a VIP is a line card for the Cisco 7500 series router.
netflow—A feature of some routers which allows them to categorize incoming packets into flows. As packets in a flow can often be treated in the same way, this classification can be used to bypass some of the work of the router and accelerate its switching operation.
service group—A group of routers and cache engines configured to run the same WCCP redirection service.
WCCP—Web Cache Communication Protocol. WCCP is a protocol for communication between routers and Web caches. Two versions currently exist: WCCP Version 1(WCCPv1) and WCCP Version 2 (WCCPv2). The two versions are incompatible. Cisco IOS images may support either of the two versions or both.
Posted: Tue Sep 19 17:43:47 PDT 2000
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