Appendix C: Web Cache Communication Protocol Version 2

Table Of Contents

Web Cache Communication Protocol Version 2

Feature Overview

Multirouter Support

Improved Security

Faster Throughput

Redirection for Multiple TCP Port-Destined Traffic

Load-Distributing Applications

Client IP Address Transparency

Restrictions

Related Documents

Supported Platforms

Supported Standards, MIBs, and RFCs

Standards

MIBs

RFCs

Prerequisites

Configuration Tasks

Configuring a Service Group Using WCCP Version 2

Running the Web Cache Service

Running the Reverse Proxy Service

Running a Custom Web Cache Service

Registering a Router to a Multicast Address

Informing a Router of Valid IP Addresses

Setting a Password for a Router and Cache Engines

Disabling Caching for Certain Clients

Verifying WCCP Configuration Settings

Monitoring and Maintaining Using WCCP Version 2

Configuration Examples

Performing a General WCCP Version 2 Configuration

Running the Web Cache Service

Running the Reverse Proxy Service

Running the Custom Web Cache Service

Registering a Router to a Multicast Address

Informing a Router of Valid IP Addresses

Setting a Password for a Router and Cache Engines

Bypassing the Cache Engine with Router Access Lists

Displaying WCCP Settings

Command Reference

clear ip wccp

ip wccp

ip wccp group-listen

ip wccp redirect exclude in

ip wccp redirect out

ip wccp version

show ip interface

show ip wccp

Web Cache Communication Protocol Version 2

This appendix describes the Web Cache Communication Protocol (WCCP) Version 2 feature. It includes information on the benefits of this feature, supported platforms, and other information you may need to work with WCCP Version 2. This appendix includes the following sections:

• Feature Overview

• Supported Platforms

• Supported Standards, MIBs, and RFCs

• Prerequisites

• Configuration Tasks

• Monitoring and Maintaining Using WCCP Version 2

• Configuration Examples

• Command Reference

Feature Overview

The Web Cache Communication Protocol (WCCP) feature allows you to use a Cache Engine to handle web traffic, reducing transmission costs and downloading time. This traffic includes user requests to view pages and graphics on
World Wide Web servers, whether internal or external to your network, and the replies to those requests. When a user requests a page from a web server (located on the Internet), the router sends the request to a Cache Engine. If the Cache Engine has a copy of the requested page in storage, the Cache Engine sends the user that page. Otherwise, the Cache Engine retrieves the requested page and the objects on that page from the web server, stores a copy of the page and its objects, and forwards the page and objects to the user.

WCCP transparently redirects Hypertext Transfer Protocol (HTTP) requests going to the intended server to a Cache Engine. End users do not know that the page came from the Cache Engine rather than from the originally requested web server.

WCCP Version 2 contains the following new features:

•Multiple router support

•Improved security

•Faster throughput

•Redirection of multiple TCP port-destined traffic

•Load-distributing applications capability

•Client IP addressing transparency

Multirouter Support

WCCP Version 2 enables a series of Cache Engines, called a Cache Engine cluster, to connect to multiple routers. This feature provides redundancy and a more distributed architecture for instances when a Cache Engine needs to connect to a large number of interfaces. This strategy also has the benefit of keeping all the Cache Engines in a single cluster, avoiding unnecessary duplication of web pages across several clusters.

How Version 1 Works

With WCCP Version 1, only a single router services a cluster, becoming the default home router for the cluster. In this scenario, this router is the device that performs all the IP packet redirection. Figure C-1 illustrates how this configuration appears.

Figure C-1 Cache Engine Network Configuration Using WCCP Version 1

The following sequence of events details how this process works:

1. Each Cache Engine records the IP address of the router servicing the cluster.

2. The Cache Engines then transmit their IP addresses to the router, indicating their presence to one another in the cluster.

3. The router then replies to the Cache Engines, establishing that each can connect to others in the cluster, and providing a view (a list) of Cache Engine addresses in the cluster, indicating that all can recognize one another.

4. Once the view has been established, one Cache Engine is designated the lead and indicates to the router how IP packet redirection should be performed. The lead Cache Engine is defined as one seen by all the routers in the service group and that has the lowest IP address.

How Version 2 Works

With WCCP Version 2, multiple routers can service a cluster. This allows any of the available routers in a service group to redirect packets to each of the Cache Engines in the cluster. Figure C-2 illustrates how this configuration appears.

Figure C-2 Cache Engine Network Configuration Using WCCP Version 2

You can configure the router to run one of three services:

•Web cache—a global service that sends content to a large collection of destination World Wide Web servers.

•Reverse proxy—a local service that sends content to a small number of destination World Wide Web servers.

•Custom web cache—a service that permits routers to redirect HTTP traffic to Cache Engines on a port other than port 80.

The subset of Cache Engines within a cluster and routers connected to the cluster that are running the same service is known as a service group.

WCCP Version 2 addresses the issue of multiple routers being available to the cluster by allowing either a list of routers or an IP multicast address to be created on the Cache Engine. The difference in these two strategies is as follows:

•In the multiple router strategy, the Cache Engine sends a notification of its presence to an explicit router address.

•In the multicast address strategy, the Cache Engine sends a notification to one address, which provides coverage for all routers in the service group, for example, 192.168.0.0, which will indicate packets be sent to a multicast address of 192.168.0.0, which would send a multicast packet to all routers in the service group.

If you are adding and removing routers dynamically, the multicast address strategy provides for easier configuration because you do not need to change the configuration for each device in the WCCP network.

The following sequence of events details how this process works:

1. Instead of having one central "home router," each Cache Engine defines a list of routers and stores the list in its memory.

2. Each Cache Engine announces its presence and view of the service group to the list of router IP addresses with which it has been configured. The routers reply with their view, which is a list of Cache Engine addresses in the group.

3. Once the view is consistent across all Cache Engines in the cluster, one
Cache Engine is designated the lead and sets the policy that the routers need to deploy in redirecting packets.

Also, you must perform these tasks to configure the routers that will become members of the service group:

•Configure an IP multicast address for use by the cluster.

•Enable the ip wccp command.

For network configurations in which the Cache Engine sends to a target router a packet that needs to traverse an intervening router, the router being traversed must be configured to perform IP multicast routing. You must configure two components to enable traversal over an intervening router:

•Enable IP multicast routing using the ip multicast routing command.

•Enable the interfaces to which the Cache Engines will connect to receive multicast transmissions using the ip pim command.

How Routers and Cache Engines Communicate

Routers and Cache Engines become aware of one another and form a service group using a management protocol. Once the service group has been established, one of the Cache Engines is designated to determine load assignments among the Cache Engines.

If there is a group of Cache Engines, the one seen by all routers and the one that has the lowest IP address becomes the lead Cache Engine. The role of this
Cache Engine is to determine how traffic should be allocated across
Cache Engines. The assignment information is passed to the entire service group from the designated Cache Engine so that the routers of the group can redirect the packets properly and the Cache Engines of the group can manage their load better.

Improved Security

WCCP Version 2 provides authentication that enables you to control which routers and Cache Engines become part of the service group. You use passwords and the HMAC MD5 standard set by the ip wccp [password [0-7] password] command to control service group membership.

Faster Throughput

Cisco Express Forwarding (CEF) has been integrated into WCCP Version 2 and provides fast packet redirection.

Redirection for Multiple TCP Port-Destined Traffic

WCCP Version 2 enables more TCP ports to have traffic redirected to the
Cache Engine. Previously, web-cached information could be redirected only if it was destined for TCP port 80. Many applications require packets intended for other ports to be redirected, for example, proxy-web cache handling, FTP caching, FTP proxy handling, web caching for ports other than 80, and
RealAudio, video, and telephony applications.

Packets that the Cache Engines do not service are tunneled back to the same router from which they were received. When a router receives a formerly redirected packet, it knows not to redirect it again.

The criteria for determining whether to redirect the traffic are:

•IP protocol

•Ports

•Priority

•Distribution scheme

•Default handling

Note that service information has been added to the protocol to indicate which service the WCCP messages refer to. This information is used to help verify that service group members are all using or providing the same service.

Web Cache Packet Return

WCCP Version 2 filters packets to determine which redirected packets have been returned from the Cache Engine and which ones have not. It does not redirect the ones that have been returned because the Cache Engine has determined that the packets should not be cached. WCCP Version 2 returns packets that the
Cache Engine does not service to the same router from which they were transmitted. Typical reasons why a Cache Engine would reject packets and initiate packet return are:

•The Cache Engine is overloaded and has no room to service the packets.

•The Cache Engine is filtering certain conditions that make caching packets counterproductive, for example, when IP authentication has been turned on.

Load-Distributing Applications

WCCP Version 2 has the capability to adjust the load being offered to individual Cache Engines to provide more effective use of the resources available and at the same time help to ensure high quality of service to the clients. It uses three techniques to perform this task:

•Hot spot handling allows an individual hash bucket, or a pool of IP addresses to which routers are mapped, to be distributed across all the Cache Engines.

•Load balancing allows the set of hash buckets assigned to a Cache Engine to be adjusted so that the load can be shifted from an overwhelmed
Cache Engine to other Cache Engines that have available capacity.

•Load shedding enables the router to selectively redirect the load to avoid exceeding the capacity of the Cache Engines.

Client IP Address Transparency

The Cache Engine accepts traffic and establishes the connection with the client, acting as if it were the original destination server. Once the connection is established, if the object being requested is not available on the Cache Engine, the engine then establishes its own connection out to the original destination server.

Restrictions

The following limitations apply to WCCP Version 2:

•The Time To Live (TTL) value of routers servicing a cluster must be
15 seconds or less.

•The protocol needs to include the list of routers in the service group as part of its messages to properly depict the view.

•Because the messages may now be IP multicasted, members may receive messages that will not be relevant or are duplicates. Appropriate filtering needs to be performed.

•Service groups can comprise up to 32 Cache Engines and 32 routers.

•All Cache Engines in a cluster must include all routers servicing the cluster in its configuration. If a cache within a cluster does not include one or more of the routers in its configuration, the service group will detect the inconsistency and the Cache Engine will not be allowed to operate within the service group.

•Multicast addresses must be between 224.0.0.0 and 239.255.255.255.

•WCCP works only with IP networks.

Related Documents

•Configuration Fundamentals Configuration Guide

•Configuration Fundamentals Command Reference

Supported Platforms

The following platforms are supported.

Table C-1 Supported Platforms and IOS Versions

Platform

IOS 11.1 CA

IOS 11.2 P

IOS 12.0(3)T

IOS 12.0(5)T

Cisco 2500 series

v1

v1

v2

v1/v2

Cisco 4000 series

v1

v1

v2

v1/v2

Cisco 4500 series

v1

v1

v2

v1/v2

Cisco 4700 series

v1

v1

v2

v1/v2

Cisco 7200 series

v1

v1

v2

v1/v2

Cisco 7500 series

v1

v1

v1

v1/v2

Supported Standards, MIBs, and RFCs

Standards

For descriptions of supported MIBs and how to use MIBs, see Cisco's MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

MIBs

None

RFCs

None

Prerequisites

Before you use WCCP Version 2, you must complete the following tasks:

•Properly install and configure a cluster connected to one or more routers.

•Configure IP on the interface connected to the Internet and the interface connected to the Cache Engine. The interface connected to the Cache Engine must be an Ethernet or Fast Ethernet interface.

Configuration Tasks

You can configure a router to run the web cache, custom web cache, and reverse proxy services associated with WCCP Version 2. The services can be configured simultaneously. Perform the following tasks to configure a cluster with multiple routers.

• Configuring a Service Group Using WCCP Version 2

• Running the Web Cache Service

• Running the Reverse Proxy Service

• Running a Custom Web Cache Service

• Informing a Router of Valid IP Addresses

• Setting a Password for a Router and Cache Engines

• Disabling Caching for Certain Clients

Configuring a Service Group Using WCCP Version 2

Command

Purpose

Step 1
Router(config)# ip wccp {web-cache | service-number} [group-address groupaddress] [redirect-list access-list] [group-listaccess-list] [password [0-7] password]
Turns the WCCP feature on or off for the specified service.

Step 2
Router(config-if)# ip wccp {web-cache | service-number} redirect out
Specifies "out" because in the future, WCCP may have the ability to redirect incoming packets as well as outgoing packets.

Step 3
Router(config-if)# ip wccp redirect exclude in
Allows inbound packets on this interface to be excluded from redirection.

Running the Web Cache Service

Command

Purpose

Step 1
Router(config)# ip wccp web-cache
Turns on the protocol for web caching.

Step 2
Router(config)# interface type number
Specifies an interface for web caching.

Step 3
Router(config-if)# ip wccp web-cache redirect out
Enables the check on packets to determine whether they need to be redirected to a web cache.

Running the Reverse Proxy Service

Command

Purpose

Step 1
Router(config)# ip wccp 99
Turns the WCCP feature on or off for the reverse proxy service. The value for reverse proxy
is 99.

Step 2
Router(config)# interface type number
Specifies an interface for the reverse proxy service.

Step 3
Router(config-if)# ip wccp 99 redirect out
Specifies "out" for the reverse proxy service.

Running a Custom Web Cache Service

Command

Purpose

Step 1
Router(config)# ip wccp 98
Turns the WCCP feature on or off for the custom web cache service. The value for custom web cache is 98.

Step 2
Router(config)# interface type number
Specifies an interface on which the reverse proxy service will run.

Step 3
Router(config-if)# ip wccp 98 redirect out
Specifies "out" for the custom web cache service.

Registering a Router to a Multicast Address

Command

Purpose

Step 1
Router(config)# ip wccp web-cache group-address groupipaddress
Configures the group address for the service group.

Step 2
Router(config)# interface type number
Specifies an interface that will listen for the multicast address.

Step 3
Router(config-if)# ip wccp web-cache group-listen
Configures an interface on a router to enable or disable the reception of IP multicast packets for WCCP.

Informing a Router of Valid IP Addresses

Command

Purpose

Step 1
Router(config)# ip wccp web-cache group-list access-list
Indicates to the router which Cache Engine IP addresses to allow packets from.

Step 2
Router(config)#access-list access-list number permit host host-address
Creates an access list that enables or disables traffic redirection to the
Cache Engine.

Setting a Password for a Router and Cache Engines

Command

Purpose

Step 1
Router(config)# ip wccp web-cache password [0-7] password
Sets a password for the
Cache Engine that the router is trying to access.

Disabling Caching for Certain Clients

Command

Purpose

Step 1
Router(config)# ip wccp web-cache redirect-list access-list number
Sets the access list used to enable redirection.

Step 2
Router(config)# access-list access-list number deny host host-address
Creates an access list that enables or disables traffic redirection to the Cache Engine.

Verifying WCCP Configuration Settings

Step 1 To view the configuration, enter the show running-config command.

A sample configuration follows:
Console# show running-config
Building configuration...Current configuration:!version 12.0service timestamps debug uptimeservice timestamps log uptimeno service password-encryptionservice udp-small-serversservice tcp-small-servers!hostname router4!enable secret 5 $1$nSVy$faliJsVQXVPW.KuCxZNTh1enable password alabama1!ip subnet-zeroip wccp web-cacheip wccp 99ip domain-name cisco.comip name-server 10.1.1.1ip name-server 10.1.1.2ip name-server 10.1.1.3!!!interface Ethernet0ip address 10.3.1.2 255.255.255.0no ip directed-broadcastip wccp web-cache redirect outip wccp 99 redirect outno ip route-cacheno ip mroute-cache!interface Ethernet1ip address 10.4.1.1 255.255.255.0no ip directed-broadcastip wccp 99 redirect outno ip route-cacheno ip mroute-cache!interface Serial0no ip addressno ip directed-broadcastno ip route-cacheno ip mroute-cacheshutdown!interface Serial1no ip addressno ip directed-broadcastno ip route-cacheno ip mroute-cacheshutdown!ip default-gateway 10.3.1.1ip classlessip route 0.0.0.0 0.0.0.0 10.3.1.1no ip http server!!!line con 0transport input noneline aux 0transport input allline vty 0 4password alaska1login!end

Step 2 To view values associated with WCCP variables, enter the show ip wccp command. The following output is displayed:
Console# show ip wccp
Global WCCP Information:Service Name: web-cache:Number of Cache Engines:1Number of Routers:1Total Packets Redirected:213Redirect access-list:no_linuxTotal Packets Denied Redirect:88Total Packets Unassigned:-none-Group access-list:0Total Messages Denied to Group:0Total Authentication failures:0
Service Name: 99Number of Cache Engines:1Number of Routers:2Total Packets Redirected:198Redirect access-list:-none-Total Packets Denied Redirect:0Total Packets Unassigned:0Group access-list:11Total Messages Denied to Group:0Total Authentication failures:0

Monitoring and Maintaining Using WCCP Version 2

Command

Purpose

Router# show ip wccp

or

Router# show ip wccp {web-cache | 99}
Displays global statistics related to WCCP.

Router# show ip wccp {web-cache | 99} detail
Queries the router for information about which
Cache Engines the router has detected in a specific service group. The information can be displayed for either a web cache or the reverse proxy service, which is indicated by a value of 99.

Router# show ip interface
Shows whether any ip wccp direct commands are configured on an interface.

Router# show ip wccp {web-cache | 99} view
Displays which devices in a particular service group have been detected and which Cache Engines are not visible to all other routers to which the current router is connected. The information can be displayed for either a web cache or the reverse proxy service, which is indicated by a value of 99.

Configuration Examples

This section provides the following configuration examples:

• Performing a General WCCP Version 2 Configuration

• Running the Web Cache Service

• Running the Reverse Proxy Service

• Registering a Router to a Multicast Address

• Informing a Router of Valid IP Addresses

• Setting a Password for a Router and Cache Engines

• Bypassing the Cache Engine with Router Access Lists

Performing a General WCCP Version 2 Configuration

The following example shows a general WCCP Version 2 configuration session:
ip wccp web-cache group-address 224.1.1.100 password alabama1interface ethernet0ip wccp web-cache redirect out
Running the Web Cache Service

The following example shows a web cache service configuration session:
configure terminalip wccp web-cacheinterface ethernet 0ip wccp web-cache redirect out
Running the Reverse Proxy Service

The following example shows a reverse proxy service configuration session:
configure terminalip wccp 99interface ethernet 0ip wccp 99 redirect out
Running the Custom Web Cache Service

The following example shows a custom web cache configuration session:
configure terminalip wccp 98interface ethernet 0ip wccp 98 redirect out

Registering a Router to a Multicast Address

The following example shows how to register a router to a multicast address of 192.168.0.0:
configure terminalip wccp web-cache group-address 192.168.0.0interface ethernet 0ip wccp web cache group-listen
Informing a Router of Valid IP Addresses

To achieve better security, you can use a standard access list to notify the router which IP addresses are valid addresses for a Cache Engine attempting to register with the current router. The following example shows a standard access list configuration session where the access list number is 10 for some sample hosts:
configure terminalaccess-list 10 permit host 11.1.1.1access-list 10 permit host 11.1.1.2access-list 10 permit host 11.1.1.3ip wccp web-cache group-list 10
Setting a Password for a Router and Cache Engines

The following example shows a WCCP Version 2 password configuration session where the password is alabama2:
configure terminalip wccp web-cache password alabama2
Bypassing the Cache Engine with Router Access Lists

The router can be configured with access lists to permit or deny redirection of traffic to the Cache Engine. In the following example, traffic conforming to the following criteria is not redirected by the router to the CE:

•Originating from the host 10.1.1.1 destined for any other host

•Originating from any host destined for the host 10.255.1.1
router# configure terminalrouter(config)# ip wccp web-cache redirect-list 120router(config)# access-list 120 deny ip host 10.1.1.1 anyrouter(config)# access-list 120 deny ip any host 10.255.1.1router(config)# access-list 120 permit ip any any

Traffic not explicitly permitted is implicitly denied redirection.
The access-list 120 permit ip any any command explicitly permits all traffic (from any source enroute to any destination) to be redirected to the Cache Engine. Because criteria matching occurs in the order by which the commands are entered, the global permit command is the last command entered. For further information on access lists see Cisco IOS documentation.

Displaying WCCP Settings

The following example displays WCCP settings, using the show running-config command:
Console# show running-config
Building configuration...Current configuration:!version 12.0service timestamps debug uptimeservice timestamps log uptimeno service password-encryptionservice udp-small-serversservice tcp-small-servers!hostname router4!enable secret 5 $1$nSVy$faliJsVQXVPW.KuCxZNTh1enable password alabama1!ip subnet-zeroip wccp web-cacheip wccp 99ip domain-name cisco.comip name-server 10.1.1.1ip name-server 10.1.1.2ip name-server 10.1.1.3!!!
interface Ethernet0ip address 10.3.1.2 255.255.255.0no ip directed-broadcastip wccp web-cache redirect outip wccp 99 redirect outno ip route-cacheno ip mroute-cache!interface Ethernet1ip address 10.4.1.1 255.255.255.0no ip directed-broadcastip wccp 99 redirect outno ip route-cacheno ip mroute-cache!interface Serial0no ip addressno ip directed-broadcastno ip route-cacheno ip mroute-cacheshutdown!interface Serial1no ip addressno ip directed-broadcastno ip route-cacheno ip mroute-cacheshutdown!ip default-gateway 10.3.1.1ip classlessip route 0.0.0.0 0.0.0.0 10.3.1.1no ip http server!!!line con 0transport input noneline aux 0transport input allline vty 0 4password alaska1login!end
Command Reference

This section documents new or modified commands that configure the WCCP Version 2 feature.

• clear ip wccp

• ip wccp

• ip wccp group-listen

• ip wccp redirect exclude in

• ip wccp redirect out

• ip wccp version

• show ip interface

• show ip wccp

In Cisco IOS Release 12.0(1)T or later, you can search and filter the output for show and more commands. This functionality is useful when you need to sort through large amounts of output, or if you want to exclude output that you do not need to see.

To use this functionality, enter a show or more command followed by the "pipe" character (|), one of the keywords begin, include, or exclude, and an expression that you want to search or filter on:

command | {begin | include | exclude} regular-expression
Following is an example of the show atm vc command in which you want the command output to begin with the first line where the expression "PeakRate" appears:

show atm vc | begin PeakRate
For more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module titled CLI String Search.

clear ip wccp

To remove Web Cache Communication Protocol (WCCP) statistics maintained on the router either for a particular service or for all the services, use the clear ip wccp EXEC command.

clear ip wccp {web-cache | service-number}
Syntax Description

web-cache

Directs the router to remove statistics for the web cache service.

service-number

Directs the router to remove statistics for a specified web cache service. The number can be from 0 to 99. The reverse proxy service is indicated by a value of 99.

Defaults

No default behavior or values.

Command Modes

EXEC

Command History

Release

Modification

11.1 CA

This command was introduced.

11.2 P

This command was introduced.

12.0(3)T

This command has been expanded to be explicit about service.

Usage Guidelines

Use the show ip wccp and show ip wccp detail commands to display WCCP statistics.

Example
clear ip wccp web cache
Related Commands

Command

Description

ip wccp

Directs a router to enable or disable the support for a service group.

show ip wccp

Displays global statistics related to the WCCP feature.

ip wccp

To direct a router to enable or disable the support for a Cache Engine service group, use the ip wccp global configuration command. To remove the ability of a router to control support for a service group, use the no form of this command.

ip wccp {web-cache | service-number} [group-address groupaddress] [redirect-list access-list] [group-list access-list] [password [0-7] password]

no ip wccp {web-cache | service-number} [group-address groupaddress] [redirect-list access-list] [group-list access-list] [password [0-7] password]

Syntax Description

web-cache

Enables the web cache service.

service-number

The identification number of the Web Cache Communication Protocol (WCCP) service being controlled by a router. The number can be from 0 to 99. The reverse proxy service is indicated by a value of 99.

group-address

(Optional.) Directs the router to use a specified multicast IP address for communication with the WCCP service group.

groupaddress

(Optional.) A multicast address used by the router to determine which Cache Engine should receive redirected messages.

redirect-list

(Optional.) Directs the router to use an access list to control traffic redirected to this service group.

access-list

(Optional.) A string (not to exceed 64 characters) that is the name of the access list that determines which traffic is redirected to a Cache Engine.

group-list

(Optional.) Directs the router to use an access list to determine which Cache Engines are allowed to participate in the service group.

access-list

(Optional.) A string (not to exceed 64 characters) that is the name of the access list that determines which Cache Engines are allowed to participate in the service group.

password

(Optional.) A string that directs the router to apply MD5 authentication to messages received from the service group specified by the service name given. Messages that are not accepted by the authentication are discarded.

0-7

(Optional.) A value that indicates the HMAC MD5 algorithm used to encrypt the password. This value is generated when an encrypted password is created for the Cache Engine.

password

(Optional.) The password name that is combined with the HMAC MD5 value to create security for the connection between the router and the Cache Engine.

Defaults

This command is disabled by default.

Command Modes

Global configuration

Command History

Release

Modification

12.0(3)T

This command was introduced.

Example

The following example shows a router configured to run WCCP reverse proxy service, using (listening to) the multicast address of 192.168.0.0:
ip wccp 99 group-address 192.168.0.0
Related Commands

Command

Description

ip wccp group-listen

Configures an interface on a router to enable or disable the reception of IP multicast packets for the WCCP feature.

ip wccp group-listen

To configure an interface on a router to enable or disable the reception of IP multicast packets for the Web Cache Communication Protocol (WCCP) feature, use the ip wccp group-listen interface configuration command. To remove control of the reception of IP multicast packets for the WCCP feature, use the no form of this command.

ip wccp {web-cache | service-number} group-listen
no ip wccp {web-cache | service-number} group-listen
Syntax Description

web-cache

Directs the router to transmit packets to 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. The reverse proxy service is indicated by a value of 99.

Defaults

This command is disabled by default.

Command Modes

Interface configuration

Command History

Release

Modification

12.0(3)T

This command was introduced.

Example

The following example shows that multicast packets have been enabled for a web cache with an address of 192.168.0.0.
configure terminalip wccp web-cache group-address 192.168.0.0interface ethernet 0ip wccp web cache group-listen
Related Commands

Command

Description

ip wccp

Directs a router to enable or disable the support for a service group.

ip wccp redirect out

Configures an interface to enable or disable the exclusion of a redirection check for packets that were received on the interface.

ip wccp redirect exclude in

To configure an interface to enable or disable excluding packets received on an interface from being redirected to a Cache Engine, use the ip wccp redirect exclude in interface configuration command. To disable a router's ability to verify that only appropriate packets are being redirected to a Cache Engine, use the no form of this command.

ip wccp redirect exclude in
no ip wccp redirect exclude in
Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values.

Command Modes

Interface configuration

Command History

Release

Modification

12.0(3)T

This command was introduced.

Usage Guidelines

Note that the command is global to all the services and should be applied to any inbound interface that has been configured to be excluded from redirection on an outbound interface that the traffic will traverse.

Example
configure terminalip wccp 99interface ethernet0ip wccp redirect exclude in
Related Commands

Command

Description

ip wccp

Directs a router to enable or disable the support for a service group.

ip wccp redirect out

Configures an interface to enable or disable the exclusion of a redirection check for packets that were received on the interface.

ip wccp redirect out

To configure an interface to enable a router's ability to verify that appropriate packets are being redirected to a Cache Engine, use the ip wccp redirect out interface configuration command. To disable a router's ability to verify that only appropriate packets being redirected to a Cache Engine, use the no form of this command.

ip wccp {web-cache | service-number} redirect out
no ip wccp {web-cache | service-number} redirect out
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. The reverse proxy service is indicated by a value of 99.

Defaults

No default behavior or values.

Command Modes

Interface configuration

Command History

Release

Modification

12.0(3)T

This command was introduced.

Example
configure terminalip wccp 99interface ethernet0ip wccp 99 redirect out
Related Commands

Command

Description

ip wccp redirect exclude in

Configures an interface to enable or disable excluding packets received on an interface from being cached.

ip wccp version

To configure the WCCP version number, use the ip wccp version global configuration command. The default WCCP version is Version 2. Use this command to override the default.

ip wccp version {1 | 2}
Syntax Description

1

Enables WCCP Version 1

2

Enables WCCP Version 2

Defaults

No default behavior or values.

Command Modes

Global configuration

Command History

Release

Modification

12.0(5)T

This command was introduced.

Example
ip wccp version 1
show ip interface

To display status about any ip wccp direct commands configured on an interface, use the show ip interface EXEC command.

show ip interface [type - number]
Syntax Description

type-number

(Optional.) The interface number whose status is being displayed.

Defaults

No default behavior or values.

Command Modes

EXEC

Command History

Release

Modification

10.0

This command was introduced.

12.0

This command was enhanced.

12.0(3)T

This command was enhanced to include status of
ip wccp redirect out and ip wccp redirect exclude add in commands.

Usage Guidelines

The Cisco IOS software automatically enters a directly connected route in the routing table if the interface is usable. A usable interface is one through which the software can send and receive packets. If the software determines that an interface is not usable, it removes the directly connected routing entry from the routing table. Removing the entry allows the software to use dynamic routing protocols to determine backup routes to the network (if any).

If the interface can provide two-way communication, the line protocol is indicated to be up. If the interface hardware is usable, the interface is indicated to be up.

If you specify an optional interface type, you will see information on that specific interface only.

If you specify no optional arguments, you will see information on all the interfaces.

When an asynchronous interface is encapsulated with Point-to-Point Protocol (PPP) or Serial Line Internet Protocol (SLIP), IP fast switching is enabled. A show ip interface command on an asynchronous interface encapsulated with PPP or SLIP displays a message indicating that IP fast switching is enabled.

Example

The following example displays output from the show ip interface command, using the interface e3/0:
show ip interface e3/0
Ethernet3/0 is upInternet address is 17.1.1.38/24Broadcast address is 255.255.255.255Address determined by non-volatile memoryMTU is 1500 bytesHelper address is not setDirected broadcast forwarding is enabledOutgoing access list is not setInbound access list is not setProxy ARP is enabledSecurity level is defaultSplit horizon is enabledICMP redirects are always sentICMP unreachables are always sentICMP mask replies are never sentIP fast switching is enabledIP fast switching on the same interface is disabledIP Optimum switching is enabledIP multicast fast switching is enabledRouter Discovery is disabledIP output packet accounting is disabledIP access violation accounting is disabledTCP/IP header compression is disabledProbe proxy name replies are disabledGateway Discovery is disabledPolicy routing is disabledNetwork address translation is disabledWCCP Redirect outbound is enabledWCCP Redirect exclude is disabled

Table C-2 describes the fields shown in the example.

Table C-2 show ip interface Field Descriptions

Field

Description

Ethernet 3/0 is up

If the interface hardware is usable, the interface is marked "up." For an interface to be usable, both the interface hardware and line protocol must be up.

Internet address

Shows the IP address of the interface.

Broadcast address

Shows the broadcast address.

Address determined by

Indicates how the IP address of the interface was determined.

MTU

Shows the Maximum Transmission Unit (MTU), or the maximum size of packets allowed to be transmitted from the router to a Cache Engine.

Helper address

Shows a helper address, if one has been set.

Directed broadcast forwarding

Shows a secondary address, if one has been set.

Outgoing access list

Indicates whether the interface has an outgoing access list set.

Inbound access list

Indicates whether the interface has an incoming access list set.

Proxy ARP

Specifies the IP Security Option (IPSO) security level set for this interface.

Security level

Specifies the default IPSO security level for this interface.

Split horizon

Specifies that routing updates sent to a particular neighbor router should not contain information about routes that were learned from that neighbor.

ICMP redirects

Indicates whether Internet Control Message Protocol (ICMP) redirects will be sent on this interface.

ICMP unreachables

Indicates whether unreachable messages will be sent on this interface.

ICMP mask replies

Indicates whether ICMP mask messages that tests node reachability across the network will be suppressed.

IP fast switching

Indicates whether fast switching has been enabled for this interface. It is generally enabled on serial interfaces, such as this one.

IP fast switching on the same interface

Indicates whether fast switching has been disabled for this interface. It is generally enabled on serial interfaces, such as this one.

IP Optimum switching

Indicates whether the IP Optimum switching feature has been turned on.

IP multicast fast switching

Indicates whether the IP multicast fast switching feature has been turned on.

Router Discovery

Indicates whether the Cisco Discovery Protocol has been turned off.

IP output packet accounting

Indicates whether the output packet counter has been turned off.

IP access violation accounting

Indicates whether the feature that counts unauthorized access events on the router has been turned off.

TCP/IP header compression

Indicates whether compression is enabled or disabled.

Probe proxy name replies

Indicates whether HP Probe proxy name replies are generated.

Gateway Discovery

Indicates whether the gateway discovery option has been turned off.

Policy routing

Indicates whether the policy routing option has been turned off.

Network address translation

Indicates whether the status of the network address translation feature has been enabled or disabled.

WCCP Redirect outbound

Indicates whether packets received on an interface are redirected to a Cache Engine. This field can be enabled or disabled.

WCCP Redirect exclude

Indicates whether packets targeted for an interface will be excluded from being redirected to a Cache Engine. This field can be enabled or disabled.

Related Commands

Command

Description

show ip wccp

Displays global statistics related to the Web Cache Communication Protocol feature.

show ip wccp

To display global statistics related to the Web Cache Communication Protocol (WCCP) feature, use the show ip wccp EXEC command.

show ip wccp {web-cache | service-number} [view | detail]
Syntax Description

web-cache

Directs the router to display statistics for 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. The reverse proxy service is indicated by a value of 99. The custom web cache service is indicated by a value of 98.

view

(Optional.) Directs the router to display statistics for the WCCP view configuration.

detail

(Optional.) Directs the router to display statistics for the WCCP detail configuration.

Defaults

No default behavior or values.

Command Modes

EXEC

Command History

Release

Modification

11.1 CA and 11.2 P

This command was introduced.

12.0(3)T

The user was allowed to query the router for the current global configuration information in use by either a single service or all services.

Usage Guidelines

Use the clear ip wccp command to reset the counter for the "Packets Redirected" information.

Examples

The following example displays output from the show ip wccp command:
show ip wccp
Global WCCP Information:Service Name: web-cache:Number of Cache Engines:1Number of Routers:1Total Packets Redirected:213Redirect access-list: no_linuxTotal Packets Denied Redirect:88Total Packets Unassigned:-none-Group access-list:0Total Messages Denied to Group:0Total Authentication failures:0
Service Name: 1Number of Cache Engines:1Number of Routers:2Total Packets Redirected:198Redirect access-list:-none-Total Packets Denied Redirect:0Total Packets Unassigned:0Group access-list:11Total Messages Denied to Group:0Total Authentication failures:0

Table C-3 describes the fields shown in the example.

Table C-3 show ip wccp Field Descriptions

Field

Description

Service Name

Service that is detailed in the display output.

Number of Cache Engines

Number of Cache Engines using the router as their home router.

Number of Routers

Number of routers in the service group.

Total Packets Redirected

Total number of packets redirected by the router.

Redirect access-list

Name or number of the access list that determines which packets will be redirected.

Total Packets Denied Redirect

Total number of packets that were not redirected because they did not match the access list.

Total Packets Unassigned

Number of packets that were not redirected because they were not assigned to any Cache Engine. Packets may not be assigned during initial discovery of
Cache Engines or when a Cache Engine is dropped from a cluster.

Group access-list

Cache Engine that is allowed to connect to the router.

Total Messages Denied to Group

Number of messages disallowed by the router because they did not meet all the requirements of the service group.

Total Authentication failures

Number of password authentication failures.

The following example displays output from the show ip wccp web-cache detail EXEC command. This command displays Cache Engine and WCCP router statistics for a particular service group:
show ip wccp web-cache detail
WCCP Router information:IP Address 192.168.88.10Protocol Version: 2.0
WCCP Cache-Engine InformationIP Address: 192.168.88.11Protocol Version: 2.0State: UsableInitial Hash Info: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAssigned Hash Info: FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFHash Allotment: 256 (100.00%)Packets Redirected: 21345Connect Time: 00:13:46

Table C-4 describes the fields shown in the example.

Table C-4 show ip wccp detail Field Descriptions

Field

Description

WCCP Router information

The header for the area that contains fields for the IP address and version of WCCP associated with the router connected to the Cache Engine in the service group.

IP Address

The IP address of the router connected to the Cache Engine in the service group.

Protocol Version

Version of WCCP being used by the router in the service group.

WCCP Cache-Engine information

Fields for information on Cache Engines.

IP Address

IP address of the Cache Engine in the service group.

Protocol Version

Version of WCCP being used by the Cache Engine in the service group.

State

Indicates whether the Cache Engine is operating properly and can be contacted by a router and other Cache Engines in the service group.

Initial Hash Info

Initial state of the hash bucket assignment.

Assigned Hash Info

Current state of the hash bucket assignment.

Hash Allotment

Percentage of buckets assigned to the current
Cache Engine. Both a value and a percentage figure are displayed.

Packets Redirected

Number of packets that have been redirected to the
Cache Engine.

Connect Time

Amount of time the Cache Engine has been connected.

The following is sample output from the show ip wccp view EXEC command. In this case, the service number 1 has been specified.
show ip wccp service 1 view
WCCP Router Informed of:192.168.88.10192.168.88.20
WCCP Cache Engines Visible192.168.88.11192.168.88.12
WCCP Cache Engines Not Visible:-none-

If any Cache Engine is displayed under the WCCP Cache Engines Not Visible field, the Cache Engine needs to be reconfigured to add this router to it. Table C-5 describes the fields shown in the example.

Table C-5 show ip wccp view Field Descriptions

Field

Description

WCCP Routers Informed of

List of routers detected by the current router.

WCCP Cache Engines Visible

List of Cache Engines that are visible to the router and other Cache Engines in the service group.

WCCP Cache Engines Not Visible

List of Cache Engines in the service group that are not visible to the router and other Cache Engines in the service group.

Related Commands

Command

Description

ip wccp detail

Directs a router to enable or disable the support for a service group.

Platform	IOS 11.1 CA	IOS 11.2 P	IOS 12.0(3)T	IOS 12.0(5)T
Cisco 2500 series	v1	v1	v2	v1/v2
Cisco 4000 series	v1	v1	v2	v1/v2
Cisco 4500 series	v1	v1	v2	v1/v2
Cisco 4700 series	v1	v1	v2	v1/v2
Cisco 7200 series	v1	v1	v2	v1/v2
Cisco 7500 series	v1	v1	v1	v1/v2

	Command	Purpose
Step 1	`Router(config)# ip wccp {web-cache \| service-number} [group-address groupaddress] [redirect-list access-list] [group-listaccess-list] [password [0-7] password]`	Turns the WCCP feature on or off for the specified service.
Step 2	`Router(config-if)# ip wccp {web-cache \| service-number} redirect out`	Specifies "out" because in the future, WCCP may have the ability to redirect incoming packets as well as outgoing packets.
Step 3	`Router(config-if)# ip wccp redirect exclude in`	Allows inbound packets on this interface to be excluded from redirection.

	Command	Purpose
Step 1	`Router(config)# ip wccp web-cache`	Turns on the protocol for web caching.
Step 2	`Router(config)# interface type number`	Specifies an interface for web caching.
Step 3	`Router(config-if)# ip wccp web-cache redirect out`	Enables the check on packets to determine whether they need to be redirected to a web cache.

	Command	Purpose
Step 1	`Router(config)# ip wccp 99`	Turns the WCCP feature on or off for the reverse proxy service. The value for reverse proxy is 99.
Step 2	`Router(config)# interface type number`	Specifies an interface for the reverse proxy service.
Step 3	`Router(config-if)# ip wccp 99 redirect out`	Specifies "out" for the reverse proxy service.

	Command	Purpose
Step 1	`Router(config)# ip wccp 98`	Turns the WCCP feature on or off for the custom web cache service. The value for custom web cache is 98.
Step 2	`Router(config)# interface type number`	Specifies an interface on which the reverse proxy service will run.
Step 3	`Router(config-if)# ip wccp 98 redirect out`	Specifies "out" for the custom web cache service.

	Command	Purpose
Step 1	`Router(config)# ip wccp web-cache group-address groupipaddress`	Configures the group address for the service group.
Step 2	`Router(config)# interface type number`	Specifies an interface that will listen for the multicast address.
Step 3	`Router(config-if)# ip wccp web-cache group-listen`	Configures an interface on a router to enable or disable the reception of IP multicast packets for WCCP.

	Command	Purpose
Step 1	`Router(config)# ip wccp web-cache group-list access-list`	Indicates to the router which Cache Engine IP addresses to allow packets from.
Step 2	`Router(config)#access-list access-list number permit host host-address`	Creates an access list that enables or disables traffic redirection to the Cache Engine.

	Command	Purpose
Step 1	`Router(config)# ip wccp web-cache redirect-list access-list number`	Sets the access list used to enable redirection.
Step 2	`Router(config)# access-list access-list number deny host host-address`	Creates an access list that enables or disables traffic redirection to the Cache Engine.

Command	Purpose
`Router# show ip wccp` or `Router# show ip wccp {web-cache \| 99}`	Displays global statistics related to WCCP.
`Router# show ip wccp {web-cache \| 99} detail`	Queries the router for information about which Cache Engines the router has detected in a specific service group. The information can be displayed for either a web cache or the reverse proxy service, which is indicated by a value of 99.
`Router# show ip interface`	Shows whether any ip wccp direct commands are configured on an interface.
`Router# show ip wccp {web-cache \| 99} view`	Displays which devices in a particular service group have been detected and which Cache Engines are not visible to all other routers to which the current router is connected. The information can be displayed for either a web cache or the reverse proxy service, which is indicated by a value of 99.

web-cache	Directs the router to remove statistics for the web cache service.
service-number	Directs the router to remove statistics for a specified web cache service. The number can be from 0 to 99. The reverse proxy service is indicated by a value of 99.

Release	Modification
11.1 CA	This command was introduced.
11.2 P	This command was introduced.
12.0(3)T	This command has been expanded to be explicit about service.

Command	Description
ip wccp	Directs a router to enable or disable the support for a service group.
show ip wccp	Displays global statistics related to the WCCP feature.

web-cache	Enables the web cache service.
service-number	The identification number of the Web Cache Communication Protocol (WCCP) service being controlled by a router. The number can be from 0 to 99. The reverse proxy service is indicated by a value of 99.
group-address	(Optional.) Directs the router to use a specified multicast IP address for communication with the WCCP service group.
groupaddress	(Optional.) A multicast address used by the router to determine which Cache Engine should receive redirected messages.
redirect-list	(Optional.) Directs the router to use an access list to control traffic redirected to this service group.
access-list	(Optional.) A string (not to exceed 64 characters) that is the name of the access list that determines which traffic is redirected to a Cache Engine.
group-list	(Optional.) Directs the router to use an access list to determine which Cache Engines are allowed to participate in the service group.
access-list	(Optional.) A string (not to exceed 64 characters) that is the name of the access list that determines which Cache Engines are allowed to participate in the service group.
password	(Optional.) A string that directs the router to apply MD5 authentication to messages received from the service group specified by the service name given. Messages that are not accepted by the authentication are discarded.
0-7	(Optional.) A value that indicates the HMAC MD5 algorithm used to encrypt the password. This value is generated when an encrypted password is created for the Cache Engine.
password	(Optional.) The password name that is combined with the HMAC MD5 value to create security for the connection between the router and the Cache Engine.

Command	Description
ip wccp group-listen	Configures an interface on a router to enable or disable the reception of IP multicast packets for the WCCP feature.

web-cache	Directs the router to transmit packets to 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. The reverse proxy service is indicated by a value of 99.

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. The reverse proxy service is indicated by a value of 99.

Command	Description
ip wccp redirect exclude in	Configures an interface to enable or disable excluding packets received on an interface from being cached.

Release	Modification
10.0	This command was introduced.
12.0	This command was enhanced.
12.0(3)T	This command was enhanced to include status of ip wccp redirect out and ip wccp redirect exclude add in commands.

Field	Description
Ethernet 3/0 is up	If the interface hardware is usable, the interface is marked "up." For an interface to be usable, both the interface hardware and line protocol must be up.
Internet address	Shows the IP address of the interface.
Broadcast address	Shows the broadcast address.
Address determined by	Indicates how the IP address of the interface was determined.
MTU	Shows the Maximum Transmission Unit (MTU), or the maximum size of packets allowed to be transmitted from the router to a Cache Engine.
Helper address	Shows a helper address, if one has been set.
Directed broadcast forwarding	Shows a secondary address, if one has been set.
Outgoing access list	Indicates whether the interface has an outgoing access list set.
Inbound access list	Indicates whether the interface has an incoming access list set.
Proxy ARP	Specifies the IP Security Option (IPSO) security level set for this interface.
Security level	Specifies the default IPSO security level for this interface.
Split horizon	Specifies that routing updates sent to a particular neighbor router should not contain information about routes that were learned from that neighbor.
ICMP redirects	Indicates whether Internet Control Message Protocol (ICMP) redirects will be sent on this interface.
ICMP unreachables	Indicates whether unreachable messages will be sent on this interface.
ICMP mask replies	Indicates whether ICMP mask messages that tests node reachability across the network will be suppressed.
IP fast switching	Indicates whether fast switching has been enabled for this interface. It is generally enabled on serial interfaces, such as this one.
IP fast switching on the same interface	Indicates whether fast switching has been disabled for this interface. It is generally enabled on serial interfaces, such as this one.
IP Optimum switching	Indicates whether the IP Optimum switching feature has been turned on.
IP multicast fast switching	Indicates whether the IP multicast fast switching feature has been turned on.
Router Discovery	Indicates whether the Cisco Discovery Protocol has been turned off.
IP output packet accounting	Indicates whether the output packet counter has been turned off.
IP access violation accounting	Indicates whether the feature that counts unauthorized access events on the router has been turned off.
TCP/IP header compression	Indicates whether compression is enabled or disabled.
Probe proxy name replies	Indicates whether HP Probe proxy name replies are generated.
Gateway Discovery	Indicates whether the gateway discovery option has been turned off.
Policy routing	Indicates whether the policy routing option has been turned off.
Network address translation	Indicates whether the status of the network address translation feature has been enabled or disabled.
WCCP Redirect outbound	Indicates whether packets received on an interface are redirected to a Cache Engine. This field can be enabled or disabled.
WCCP Redirect exclude	Indicates whether packets targeted for an interface will be excluded from being redirected to a Cache Engine. This field can be enabled or disabled.

web-cache	Directs the router to display statistics for 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. The reverse proxy service is indicated by a value of 99. The custom web cache service is indicated by a value of 98.
view	(Optional.) Directs the router to display statistics for the WCCP view configuration.
detail	(Optional.) Directs the router to display statistics for the WCCP detail configuration.

Release	Modification
11.1 CA and 11.2 P	This command was introduced.
12.0(3)T	The user was allowed to query the router for the current global configuration information in use by either a single service or all services.

Field	Description
Service Name	Service that is detailed in the display output.
Number of Cache Engines	Number of Cache Engines using the router as their home router.
Number of Routers	Number of routers in the service group.
Total Packets Redirected	Total number of packets redirected by the router.
Redirect access-list	Name or number of the access list that determines which packets will be redirected.
Total Packets Denied Redirect	Total number of packets that were not redirected because they did not match the access list.
Total Packets Unassigned	Number of packets that were not redirected because they were not assigned to any Cache Engine. Packets may not be assigned during initial discovery of Cache Engines or when a Cache Engine is dropped from a cluster.
Group access-list	Cache Engine that is allowed to connect to the router.
Total Messages Denied to Group	Number of messages disallowed by the router because they did not meet all the requirements of the service group.
Total Authentication failures	Number of password authentication failures.

Field	Description
WCCP Router information	The header for the area that contains fields for the IP address and version of WCCP associated with the router connected to the Cache Engine in the service group.
IP Address	The IP address of the router connected to the Cache Engine in the service group.
Protocol Version	Version of WCCP being used by the router in the service group.
WCCP Cache-Engine information	Fields for information on Cache Engines.
IP Address	IP address of the Cache Engine in the service group.
Protocol Version	Version of WCCP being used by the Cache Engine in the service group.
State	Indicates whether the Cache Engine is operating properly and can be contacted by a router and other Cache Engines in the service group.
Initial Hash Info	Initial state of the hash bucket assignment.
Assigned Hash Info	Current state of the hash bucket assignment.
Hash Allotment	Percentage of buckets assigned to the current Cache Engine. Both a value and a percentage figure are displayed.
Packets Redirected	Number of packets that have been redirected to the Cache Engine.
Connect Time	Amount of time the Cache Engine has been connected.

Field	Description
WCCP Routers Informed of	List of routers detected by the current router.
WCCP Cache Engines Visible	List of Cache Engines that are visible to the router and other Cache Engines in the service group.
WCCP Cache Engines Not Visible	List of Cache Engines in the service group that are not visible to the router and other Cache Engines in the service group.

Command	Description
ip wccp detail	Directs a router to enable or disable the support for a service group.