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This appendix describes the Web Cache Communication Protocol (WCCP) Version 2 feature. It includes information on the benefits of this new feature, supported platforms, and other information you may need to work with WCCP Version 2.
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 in 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 from the intended server to a Cache Engine. End users do not know that the page came from the Cache Engine rather than the originally requested web server.
WCCP Version 2 now contains the following new features:
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.
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.
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 the other in the cluster, providing a view or a list of Cache Engine addresses in the cluster, indicating that each can recognize each other.
4. Once the view has been established, one Cache Engine is designated as 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.
With WCCP Version 2, multiple routers can service a cluster, creating contention between available routers to obtain status as the device that redirects packets for data coming from each of the Cache Engines in the cluster. Figure C-2 illustrates how this configuration appears. You can configure the router to run one of two services:
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:
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 obtains 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 they have been configured. The routers reply with their view or 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 as the lead and sets the policy that the routers need to deploy in redirecting packets.
Also, you need to configure the router that will become members of the service group:
For network configurations where 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:
Routers and Cache Engines become aware of each other 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 that has the lowest IP address becomes the lead Cache Engine. The role of this Cache Engine is to determine how traffic should be split 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.
Security between a Cache Engine and a router is now stronger because the Cache Engine's location in a cluster is more strongly circumscribed. WCCP Version 2 provides authentication that enables you to control which routers and Cache Engines become part of the service group using passwords and the HMAC MD5 standard set by the ip wccp [password [0-7] password] command.
Cisco Express Forwarding (CEF) has been integrated into WCCP Version 2 and provides fast packet redirection.
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 Real Audio, video, and telephony applications.
Packets that the Cache Engines do not service are tunneled back to the same router from where they were received. Once a router has received a formerly redirected packet, it knows not to redirect it again.
The criteria set for determining whether to redirect the traffic is as follows:
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 validate that service group members are all using or providing the same service.
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:
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:
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.
Access to multiple routers provides backup support for a failed connection between a Cache Engine and the lead router.
Security between a Cache Engine and a router is now stronger as the Cache Engine's place in a cluster is more strongly circumscribed. Also authentication is now available using the HMAC MD5 security feature.
CEF provides fast redirection by using more efficient levels of switching, specifically, the process switch.
The ability to redirect traffic destined to multiple TCP ports provides more flexibility for more applications, for example, proxy-web cache handling, FTP caching, FTP proxy handling, and Real Audio, video, and telephony applications, all targeted to various TCP ports. Previously, only applications with traffic destined to TCP port 80 could have traffic redirected.
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.
| Prior to WCCP Version 2 | Using WCCP Version 2 |
|---|---|
Only one router could access a Cache Engine server cluster. | Multiple routers can access a Cache Engine server cluster. |
Web-cached information can be redirected only if destined for TCP port 80. | Web-cached information can be redirected if destined for any TCP port. |
Information from one hash bucket could only go to one Cache Engine. | Information from one hash bucket can go to multiple Cache Engines. |
The following limitations apply to WCCP Version 2:
To understand how WCCP Version 2 works, you must understand concepts associated with the Cache Engine.
The following platforms are supported:
In Release 12.0.3, this feature is supported on these platforms:
In Release 12.0.3c, this feature is supported on these platforms:
In Release 12.0.4, this feature is supported on these platforms:
In Release 12.0.4a, this feature is supported on these platforms:
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.
None
Before you use WCCP Version 2, you must complete the following tasks:
You can configure a router to run the web cache and reverse proxy services associated with WCCP Version 2. Each service may be configured simultaneously. Perform the following tasks to configure a cluster with multiple routers.
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router(config)# ip wccp {web-cache |
service-number} [group-address groupaddress]
[redirect-list access-list] [group-list
access-list] [password [0-7] password]
| Turns the feature on or off for the specified service. | ||
| Specifies "out" because in the future, WCCP may have the ability to redirect incoming packets as well as outgoing packets. | |||
| Router(config-if)# ip wccp redirect exclude in | Allows inbound packets on this interface to be excluded from redirection. |
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router(config)# ip wccp web-cache | Turns on the protocol for web caching. | ||
| Targets an interface number for which a web cache service will run. | |||
| Router(config-if)# ip wccp web-cache redirect out | Enables the check on packets to determine if they qualify to be redirected to a web cache. |
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router(config)# ip wccp 99 | Turns the feature on or off for the reverse proxy service. The value for reverse proxy is 99. | ||
| Targets an interface on which the reverse proxy service will run. | |||
| Router(config-if)#ip wccp 99 redirect out | Specifies "out" for the reverse proxy service. |
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router(config)# ip wccp web-cache group-address groupaddress | Configures the address of the group address for the service group. | ||
| Targets an interface to listen for the multicast address. | |||
| 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. |
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router(config)# ip wccp web-cache group-list access-list | Indicates to the router which IP addresses of the Cache Engines to accept packets from. | ||
| Creates an access list that enables or disables traffic redirection to the Cache Engine. |
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router(config)# ip wccp web-cache password password | Sets a password for the Cache Engine the router is trying to access. |
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router(config)# ip wccp web-cache redirect-list access-list | Sets the access list used to enable redirection | ||
| Creates an access list that enables or disables traffic redirection to the Cache Engine. |
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 12.0 service timestamps debug uptime service timestamps log uptime no service password-encryption service udp-small-servers service tcp-small-servers ! hostname router4 ! enable secret 5 $1$nSVy$faliJsVQXVPW.KuCxZNTh1 enable password alabama1 ! ip subnet-zero ip wccp web-cache ip wccp 99 ip domain-name cisco.com ip name-server 10.1.1.1 ip name-server 10.1.1.2 ip name-server 10.1.1.3 ! ! ! interface Ethernet0 ip address 10.3.1.2 255.255.255.0 no ip directed-broadcast ip wccp web-cache redirect out ip wccp 99 redirect out no ip route-cache no ip mroute-cache ! interface Ethernet1 ip address 10.4.1.1 255.255.255.0 no ip directed-broadcast ip wccp 99 redirect out no ip route-cache no ip mroute-cache ! interface Serial0 no ip address no ip directed-broadcast no ip route-cache no ip mroute-cache shutdown ! interface Serial1 no ip address no ip directed-broadcast no ip route-cache no ip mroute-cache shutdown ! ip default-gateway 10.3.1.1 ip classless ip route 0.0.0.0 0.0.0.0 10.3.1.1 no ip http server ! ! ! line con 0 transport input none line aux 0 transport input all line vty 0 4 password alaska1 login ! end
Step 2 To view values associated with WCCP variables, enter the show ip wccp command. The following output is displayed:
show ip wccp Global WCCP Information: Service Name: web-cache: Number of Cache Engines: 1 Number of Routers: 1 Total Packets Redirected: 213 Redirect access-list: no_linux Total Packets Denied Redirect: 88 Total Packets Unassigned: -none- Group access-list: 0 Total Messages Denied to Group: 0 Total Authentication failures: 0 Service Name: 99 Number of Cache Engines: 1 Number of Routers: 2 Total Packets Redirected: 198 Redirect access-list: -none- Total Packets Denied Redirect: 0 Total Packets Unassigned: 0 Group access-list: 11 Total Messages Denied to Group: 0 Total Authentication failures: 0
| 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 on which Cache Engines of a specific service group the router has detected. 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 | Displays status about 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 having trouble becoming 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. |
This section provides the following configuration examples:
The following example shows a general WCCP Version 2 configuration session:
ip wccp web-cache group-address 224.1.1.100 password alabama1 interface ethernet0 ip wccp web-cache redirect out
The following example shows a web cache service configuration session:
configure terminal ip wccp web-cache interface ethernet 0 ip wccp web-cache redirect out
The following example shows a reverse proxy service configuration session:
configure terminal ip wccp 99 interface ethernet 0 ip wccp 99 redirect out
The following example shows how to register a router to a multicast address of 224.1.1.100:
configure terminal ip wccp web-cache group-address 224.1.1.100 interface ethernet 0 ip wccp web cache group-listen
To achieve better security, you can notify the router which IP addresses are valid addresses for a Cache Engine attempting to register with the current router, using a standard access list. The following example, shows a standard access list configuration session where the access list number is 10 for some sample hosts:
access-list 10 permit host 11.1.1.1 access-list 10 permit host 11.1.1.2 access-list 10 permit host 11.1.1.3 ip wccp web-cache group-list 10
The following example shows a WCCP Version 2 password configuration session where the password is alabama2:
configure terminal ip wccp web-cache password alabama2
To disable caching for certain clients, servers, or client/server pairs, you can use WCCP access lists. The following example shows any requests coming from 10.1.1.1 to 12.1.1.1 will bypass the cache. while all other requests will be serviced normally:
configure terminal ip wccp web-cache redirect-list 120 access-list 120 deny tcp host 10.1.1.1 access-list 120 deny tcp any host 12.1.1.1 access-list 120 permit ip any any
The following example displays WCCP settings, using the show running-config command:
Console# show running-config Building configuration... Current configuration: ! version 12.0 service timestamps debug uptime service timestamps log uptime no service password-encryption service udp-small-servers service tcp-small-servers ! hostname router4 ! enable secret 5 $1$nSVy$faliJsVQXVPW.KuCxZNTh1 enable password alabama1 ! ip subnet-zero ip wccp web-cache ip wccp 99 ip domain-name cisco.com ip name-server 10.1.1.1 ip name-server 10.1.1.2 ip name-server 10.1.1.3 ! ! ! interface Ethernet0 ip address 10.3.1.2 255.255.255.0 no ip directed-broadcast ip wccp web-cache redirect out ip wccp 99 redirect out no ip route-cache no ip mroute-cache ! interface Ethernet1 ip address 10.4.1.1 255.255.255.0 no ip directed-broadcast ip wccp 99 redirect out no ip route-cache no ip mroute-cache ! interface Serial0 no ip address no ip directed-broadcast no ip route-cache no ip mroute-cache shutdown ! interface Serial1 no ip address no ip directed-broadcast no ip route-cache no ip mroute-cache shutdown ! ip default-gateway 10.3.1.1 ip classless ip route 0.0.0.0 0.0.0.0 10.3.1.1 no ip http server ! ! ! line con 0 transport input none line aux 0 transport input all line vty 0 4 password alaska1 login ! end
This section documents new or modified commands that configure the WCCP Version 2 feature. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references.
In Cisco IOS Release 12.0(1)T or later, you can search 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-expressionFollowing 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 PeakRateFor more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module titled CLI String Search.
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}
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. |
No default behavior or values.
EXEC
| 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. |
Use the show ip wccp and show ip wccp detail commands to display WCCP statistics.
clear ip wccp web cache
| 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. |
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] text]
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 message. |
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 that will be used to encrypt the password. This value is generated when an encrypted password is created for the Cache Engine. |
text | (Optional) The password name that will be combined with the HMAC MD5 value to create security for the connection between the router and the Cache Engine. |
No default behavior or values.
Global configuration
| Release | Modification |
|---|---|
12.0(3)T | This command was introduced. |
The command is disabled by default.
The following example shows a router configured to run WCCP reverse proxy service, using (listening to) the multicast address of 224.1.1.1:
ip wccp 99 group-address 224.1.1.1
| 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. |
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
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. |
This command is disabled by default.
Interface configuration
| Release | Modification |
|---|---|
12.0(3)T | This command was introduced. |
The following example shows that multicast packets have been enabled for a web cache with an address of 224.1.1.100.
configure terminal ip wccp web-cache group-address 224.1.1.100 interface ethernet 0 ip wccp web cache group-listen
| 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. |
To configure an interface to enable or disable excluding packets received on an interface from being cached, use the ip wccp redirect exclude in global configuration command. To disable a router's ability to verify appropriate packets being redirected to a Cache Engine, use the no form of this command.
ip wccp redirect exclude inThis command has no arguments or keywords.
No default behavior or values.
Global configuration
| Release | Modification |
|---|---|
12.0(3)T | This command was introduced. |
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.
| 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. |
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 appropriate packets being redirected to a Cache Engine, use the no form of this command.
ip wccp {web-cache | service-number} redirect out
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. |
No default behavior or values.
Interface configuration
| Release | Modification |
|---|---|
12.0(3)T | This command was introduced. |
configure terminal ip wccp 99 interface ethernet 0 ip wccp 99 redirect out
| Command | Description |
ip wccp redirect exclude in | Configures an interface to enable or disable excluding packets received on an interface from being cached. |
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]
type-number | (Optional) The interface number whose status is being displayed. |
No default behavior or values.
EXEC
| Release | Modification |
|---|---|
10.0 | This command was first 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. |
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 running. If the interface hardware is usable, the interface is indicated to be running.
If you specify an optional interface type, you will see only information on that specific interface.
If you specify no optional arguments, you will see information on all the interfaces.
When an asynchronous interface is encapsulated with Point-to-Point Protocl (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.
The following example displays output from the show ip interface command, using the interface e3/0:
show ip interface e3/0 Ethernet3/0 is up Internet address is 17.1.1.38/24 Broadcast address is 255.255.255.255 Address determined by non-volatile memory MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is enabled Outgoing access list is not set Inbound access list is not set Proxy ARP is enabled Security level is default Split horizon is enabled ICMP redirects are always sent ICMP unreachables are always sent ICMP mask replies are never sent IP fast switching is enabled IP fast switching on the same interface is disabled IP Optimum switching is enabled IP multicast fast switching is enabled Router Discovery is disabled IP output packet accounting is disabled IP access violation accounting is disabled TCP/IP header compression is disabled Probe proxy name replies are disabled Gateway Discovery is disabled Policy routing is disabled Network address translation is disabled WCCP Redirect outbound is enabled WCCP Redirect exclude is disabled
Table C-1 describes the fields shown in the example.
| Field | Description |
|---|---|
Ethernet3/0 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 is | The IP address of the interface. |
Broadcast address is | Shows the broadcast address. |
Address determined by non-volatile memory | Indicates how the IP address of the interface was determined. |
MTU is 1500 bytes | Maximum Transmission Unit (MTU) or the maximum size of packets allowed to be transmitted from the router to a Cache Engine. |
Helper address is not set | Shows a helper address, if one has been set. |
Directed broadcast forwarding is enabled | Shows a secondary address, if one has been set. |
Outgoing access list is not set | Indicates whether the interface has an outgoing access list set. |
Inbound access list is not set | Indicates whether the interface has an incoming access list set. |
Proxy ARP is enabled | Specifies the IPSO security level set for this interface. |
Security level is default | Specifies the default IPSO security level for this interface. |
Split horizon is enabled | Specifies that routing updates sent to a particular neighbor router should not contain information about routes that were learned from that neighbor. |
ICMP redirects are always sent | Specifies whether redirects will be sent on this interface. |
ICMP unreachables are always sent | Specifies whether unreachable messages will be sent on this interface. |
ICMP mask replies are never sent | Internet Control Message Protocol mask messages that tests node reachability across the network are suppressed. |
IP fast switching is enabled | Specifies 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 is disabled | Specifies whether fast switching has been disabled for this interface. It is generally enabled on serial interfaces, such as this one. |
IP Optimum switching is enabled | The IP Optimum switching feature has been turned on. |
IP multicast fast switching is enabled | The IP multicast fast switching feature has been turned on. |
Router Discovery is disabled | Cisco Discovery Protocol has been turned off. |
IP output packet accounting is disabled | The output packet counter has been turned off. |
IP access violation accounting is disabled | The feature that counts unauthorized access events on the router has been turned off. |
TCP/IP header compression is disabled | Indicates whether compression is enabled or disabled. |
Probe proxy name replies are disabled | Indicates whether HP Probe proxy name replies are generated. |
Gateway Discovery is disabled | The gateway discovery option has been turned off. |
Policy routing is disabled | The policy routing option has been turned off. |
Network address translation is disabled | The status of the network address translation feature. This field can be enabled or disabled. |
WCCP Redirect outbound is enabled | Indicates the status of whether packets received on an interface are redirected to a Cache Engine. This field can be enabled or disabled. |
WCCP Redirect exclude is disabled | Indicates the status of whether packets targeted for an interface will be exluded from being redirected to a Cache Engine. This field can be enabled or disabled. |
| Command | Description |
show ip wccp detail | Queries the router for information on which other members of a specific service group the router has detected. |
show ip wccp | Displays global statistics related to the Web Cache Communication Protocol feature. |
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]
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. |
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. |
No default behavior or values.
EXEC
| Release | Modification |
|---|---|
11.2 P | This command was introduced in Cisco IOS Release 11.2 P and Release 11.1 CA. |
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. |
Use the clear ip wccp command to reset the counter for the "Packets Redirected" information.
The following example is sample output from the show ip wccp command:
show ip wccp Global WCCP Information: Service Name: web-cache: Number of Cache Engines: 1 Number of Routers: 1 Total Packets Redirected: 213 Redirect access-list: no_linux Total Packets Denied Redirect: 88 Total Packets Unassigned: -none- Group access-list: 0 Total Messages Denied to Group: 0 Total Authentication failures: 0 Service Name: 1 Number of Cache Engines: 1 Number of Routers: 2 Total Packets Redirected: 198 Redirect access-list: -none- Total Packets Denied Redirect: 0 Total Packets Unassigned: 0 Group access-list: 11 Total Messages Denied to Group: 0 Total Authentication failures: 0
Table C-2 describes the fields shown in the example.
| Field | Description |
|---|---|
Service Name | Indicates which service is detailed. |
Number of Cache Engines | Number of Cache Engines using the router as their home router. |
Number of Routers | The number of routers in the service group. |
Total Packets Redirected | Total number of packets redirected by the router. |
Redirect access-list | The 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 is dropped from a cluster. |
Group access-list | Indicates which Cache Engine is allowed to connect to the router. |
Total Messages Denied to Group | Indicates the number of messages disallowed by the router because they did not meet all the requirements of the service group. |
Total Authentication failures | The number of instances where a password did not match. |
| Command | Description |
ip wccp | Directs a router to enable or disable the support for a service group. |
show ip wccp detail | Queries the router for information on which other members of a specific service group the router has detected. |
To query the router for information on which Cache Engines of a specific service group the router has detected, use the show ip wccp detail EXEC command.
show ip wccp {web-cache | service-number} detail
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. |
No default behavior or values.
EXEC
| Release | Modification |
|---|---|
11.1 CA | This command was introduced. |
11.2 P | This command was introduced. |
12.0(3)T | This command was expanded to indicate that a router has not had a Cache Engine mapped to it. |
The following example displays Cache Engine and Web Cache Communication Protocol (WCCP) router statistics for a particular service group:
show ip wccp web-cache detail WCCP Router information: IP Address 192.168.88.10 Protocol Version: 2.0 WCCP Cache-Engine Information IP Address: 192.168.88.11 Protocol Version: 2.0 State: Usable Initial Hash Info: AAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAA Assigned Hash Info: FFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFF Hash Allotment: 256 (100.00%) Packets Redirected: 21345 Connect Time: 00:13:46
Table C-3 describes the fields shown in the example.
| 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 | The version of WCCP being used by the router in the service group. |
WCCP Cache-Engine information | Contains fields for information on Cache Engines. |
IP Address | The IP address of the Cache Engine in the service group. |
Protocol Version | The 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 | The initial state of the hash bucket assignment. |
Assigned Hash Info | The current state of the hash bucket assignment. |
Hash Allotment | The percent of buckets assigned to the current Cache Engine. Both a value and a percent figure are displayed. |
Packets Redirected | The number of packets that have been redirected to the Cache Engine. |
Connect Time | The amount of time it took for the Cache Engine to connect to the router. |
| Command | Description |
show ip wccp view | Displays which Cache Engines in a particular service group have or have not been detected by all other routers to which the current router is connected. |
show ip wccp | Displays global statistics related to the WCCP feature. |
To display which devices in a particular service group have or have not been detected by all other routers to which the current router is connected, use the show ip wccp view EXEC command.
show ip wccp {web-cache | service-number} view
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. |
No default behavior or values.
EXEC
| Release | Modification |
|---|---|
11.1 CA | This command was introduced. |
11.2 P | This command was introduced. |
12.0(3)T | This command was expanded to show a router that does not have a Cache Engine mapped to it. |
The following sample output from the show ip wccp service 1 view command:
show ip wccp service 1 view WCCP Router Informed of: 192.168.88.10 192.168.88.20 WCCP Cache Engines Visible 192.168.88.11 192.168.88.12 WCCP Cache Engines Not Visible: -none-
If any Cache Engine is displayed under the WCCP Cache Engines Not Visible field, the router needs to be reconfigured to map the Cache Engine that is not visible to it. Table C-4 describes the fields shown in the example.
| Field | Description |
|---|---|
WCCP Routers Informed of | A list of routers detected by the current router. |
WCCP Cache Engines Visible | A list of Cache Engines that are visible to the router and other Cache Engines in the service group. |
WCCP Cache Engines Not Visible | A list Cache Engines in the service group that are not visible to the router and other Cache Engines in the service group. |
| Command | Description |
show ip wccp detail | Queries the router for information on which other members of a specific service group the router has detected. |
show ip wccp | Displays global statistics related to the Web Cache Communication Protocol feature. |
Cache Engine---A device that stores objects being downloaded from the web for future use by the host.
Cache Engine cluster---A collection of Cache Engines that are controlled by one or more routers.
Cisco Express Forwarding (CEF)---A scalable, distributed, Layer 3 switching solution designed to meet performance requirements of the Internet and enterprise networks.
hash buckets---A pool of IP addresses to which individual servers are mapped.
reverse proxy service---A service that duplicates network content and distributes it across a small number of destination World Wide Web servers.
service group---A subset of Cache Engines within a cluster and routers connected to the cluster that are running the same service, either web cache or reverse proxy.
view---A list of addresses of the Cache Engines in the service group.
WCCP Version 1---A protocol that allows you to use a Cache Engine to handle World Wide Web traffic, thus reducing transmission costs and downloading time. The specified services can be mapped to multiple routers. The Cache Engines in the cluster can be mapped to only one router.
WCCP Version 2---A protocol that allows you to use a Cache Engine to handle World Wide Web traffic in a similar manner to WCCP Version 1. Specified services can be mapped to multiple routers.
web cache service---A service that handles large collections of destination World Wide Web servers with various IP addresses throughout the network. The network content, rather than being duplicated across all Cache Engines, is assigned to a particular Cache Engine.
Posted: Fri Jul 2 15:38:16 PDT 1999
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