Cisco WS-X6K-SUP1A-PFC= Software Guide - Page 217

Local Proxy ARP, WCCP Layer 2 Redirection, Auto State Feature, With Release 12.12E or later releases

Page 217 highlights

Chapter 12 Configuring InterVLAN Routing Configuring InterVLAN Routing on the MSFC Local Proxy ARP With Release 12.1(2)E or later releases, the Local Proxy Address Resolution Protocol (ARP) allows the MSFC to respond to ARP requests for IP addresses within a subnet where normally no routing is required. With local proxy ARP enabled, the MSFC responds to all ARP requests for IP addresses within the subnet and forwards all traffic between hosts in the subnet. Use this feature only on subnets where hosts are intentionally prevented from communicating directly by the configuration on the switch to which they are connected. Local proxy ARP is disabled by default. Enter the ip local-proxy-arp interface configuration command to enable local proxy ARP on an interface. Enter the no ip local-proxy-arp interface configuration command to disable the feature. The Internet Control Message Protocol (ICMP) redirects are disabled on interfaces where local proxy ARP is enabled. WCCP Layer 2 Redirection Note Supervisor Engine 1 with the Policy Feature Card (PFC) supports this feature with Release 12.1(2)E or later releases. Supervisor Engine 2 with PFC2 supports this feature with Release 12.1(3a)E or later releases. Web Cache Communication Protocol (WCCP) Layer 2 redirection allows directly connected Cisco Cache Engines to use Layer 2 redirection, which is more efficient than Layer 3 redirection, through generic routing encapsulation (GRE). You can configure a directly connected Cache Engine to negotiate use of WCCP Layer 2 redirection. WCCP Layer 2 redirection requires no configuration on the MSFC. Enter the show ip wccp web-cache detail command to display which redirection method is in use for each cache. Follow these guidelines when using this feature: • WCCP Layer 2 redirection feature sets the IP flow mask to full-flow mode. • You can configure the Cisco Cache Engine software release 2.2 or later releases to use WCCP Layer 2 redirection. • Layer 2 redirection takes place on the switch and is not visible to the MSFC. Entering the show ip wccp web-cache detail command on the MSFC displays statistics for only the first packet of a Layer 2 redirected flow, which provides an indication of how many flows, rather than packets, are using Layer 2 redirection. Entering the show mls entries command on the supervisor engine displays the other packets in the Layer 2 redirected flows. Configure the Cisco IOS WCCP as described in the Cisco IOS Configuration Fundamentals Configuration Guide at http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/fun_c/fcprt3/fcd305.htm Auto State Feature The auto state feature shuts down (or brings up) Layer 3 interfaces/subinterfaces on the MSFC and the Multilayer Switch Module (MSM) when the following port configuration changes occur on the switch: • When the last external port on a VLAN goes down, all Layer 3 interfaces/subinterfaces on that VLAN shut down (are autostated) unless sc0 is on the VLAN or another router is in the chassis with an interface/subinterface in the VLAN. When a Layer 3 interface goes down, this message is reported to the console for each Layer 3 interface: %AUTOSTATE-6-SHUT_DOWN 78-13315-02 Catalyst 6000 Family Software Configuration Guide-Releases 6.3 and 6.4 12-5

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12-5
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
78-13315-02
Chapter 12
Configuring InterVLAN Routing
Configuring InterVLAN Routing on the MSFC
Local Proxy ARP
With Release 12.1(2)E or later releases, the Local Proxy Address Resolution Protocol (ARP) allows the
MSFC to respond to ARP requests for IP addresses within a subnet where normally no routing is
required. With local proxy ARP enabled, the MSFC responds to all ARP requests for IP addresses within
the subnet and forwards all traffic between hosts in the subnet. Use this feature only on subnets where
hosts are intentionally prevented from communicating directly by the configuration on the switch to
which they are connected.
Local proxy ARP is disabled by default. Enter the
ip local-proxy-arp
interface configuration command
to enable local proxy ARP on an interface. Enter the
no ip local-proxy-arp
interface configuration
command to disable the feature. The Internet Control Message Protocol (ICMP) redirects are disabled
on interfaces where local proxy ARP is enabled.
WCCP Layer 2 Redirection
Note
Supervisor Engine 1 with the Policy Feature Card (PFC) supports this feature with Release 12.1(2)E
or later releases. Supervisor Engine 2 with PFC2 supports this feature with Release 12.1(3a)E or later
releases.
Web Cache Communication Protocol (WCCP) Layer 2 redirection allows directly connected Cisco
Cache Engines to use Layer 2 redirection, which is more efficient than Layer 3 redirection, through
generic routing encapsulation (GRE). You can configure a directly connected Cache Engine to negotiate
use of WCCP Layer 2 redirection. WCCP Layer 2 redirection requires no configuration on the MSFC.
Enter the
show ip wccp web-cache detail
command to display which redirection method is in use for
each cache. Follow these guidelines when using this feature:
WCCP Layer 2 redirection feature sets the IP flow mask to full-flow mode.
You can configure the Cisco Cache Engine software release 2.2 or later releases to use WCCP
Layer 2 redirection.
Layer 2 redirection takes place on the switch and is not visible to the MSFC. Entering the
show ip
wccp web-cache detail
command on the MSFC displays statistics for only the first packet of a
Layer 2 redirected flow, which provides an indication of how many flows, rather than packets, are
using Layer 2 redirection. Entering the
show mls entries
command on the supervisor engine
displays the other packets in the Layer 2 redirected flows.
Configure the Cisco IOS WCCP as described in the
Cisco IOS Configuration Fundamentals
Configuration Guide
at
Auto State Feature
The auto state feature shuts down (or brings up) Layer 3 interfaces/subinterfaces on the MSFC and the
Multilayer Switch Module (MSM) when the following port configuration changes occur on the switch:
When the last external port on a VLAN goes down, all Layer 3 interfaces/subinterfaces on that
VLAN shut down (are autostated) unless sc0 is on the VLAN or another router is in the chassis with
an interface/subinterface in the VLAN. When a Layer 3 interface goes down, this message is
reported to the console for each Layer 3 interface:
%AUTOSTATE-6-SHUT_DOWN