Cisco Systems 8540 CSR, 8510 CSR appendix Configuring Snooping, Restrictions on Port Snooping

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Chapter 4 Configuring Interfaces

Configuring Snooping

Restrictions on Port Snooping

The following restrictions apply to port snooping:

The combined physical bandwidth of the source ports must not exceed the physical bandwidth of the destination port.

The snooping source port and destination port cannot be the same port.

Port snooping is not available on the eight-port Gigabit Ethernet interfaces.

About the Snooping Destination Port

The snooping destination port can be any port in the system, except for the management port on the route processor (Ethernet0) and ports configured for Fast EtherChannel. Typically, the destination port has a network analyzer or RMON probe attached to it.

When in snooping mode, all the existing connections to the snooping destination port are set to the down state, and the snooping destination port cannot perform any Layer 2 or Layer 3 operations in this state. The receive side of the snooping destination port is also disabled when in snooping mode. The snooping destination port resumes normal operation only when snooping mode is disabled.

About the Snooping Source Port

A source port is a port monitored by the snooping operation. The snooping source port can be on any interface module.

The normal operation of a snooping source port is not altered during snooping operations. Any port with bandwidth less than or equal to the bandwidth of the snooping destination port can function as a snooping source port.

Layer 3 switching software supports snooping from multiple source ports to a destination port. The total bandwidth of the snooping source ports must not exceed the bandwidth of the snooping destination port. For example, up to ten Fast Ethernet ports can be configured as snooping source ports to a 1-Gb Ethernet destination port.

Configuring Snooping

To enable port-based snooping on an interface, perform the following steps, beginning in global configuration mode:

Note You must shut down the destination interface before you enable snooping mode. To bring the interface up after you have finished configuring snooping, be sure to issue a no shutdown command.

 

 

Layer 3 Switching Software Feature and Configuration Guide

 

 

 

 

 

 

 

78-6235-04, Cisco IOS Release 12.0(10)W5(18)

 

 

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Contents Configuring Interfaces Overview of Interface Configuration Media Access Control AddressInterface Port Identifier General Instructions for Configuring Interfaces Router# configure terminalRouterconfig# interface gigabitethernet 1/0/1 About Layer 3 Switching Interfaces Example Initially Configuring Gigabit Ethernet InterfacesCommand Purpose About the Enhanced Gigabit Ethernet Interfaces CatalystInitially Configuring Fast Ethernet Interfaces Verifying the Ethernet Interface ConfigurationCommand Description Examples Router# show interface gigabitethernet 0/0/0Router# show interface fastethernet 1/0/0 About Virtual LANs Configuring ISL Vlan EncapsulationRouterconfig# bridge bridge-group protocol ieee Enters subinterface configuration modeRouterconfig-subif# Configure the Fast Ethernet main interface Routerconfig-if#Routerconfig-subif#interface fastethernet 3/0/1 Configuring 802.1Q Vlan EncapsulationRouterconfig# interface fastethernet 1/0/1.1 Routerconfig-subif#interface fastethernet 1/0/0Ieee Bridge-groupAbout Packet over Sonet Catalyst Monitoring Vlan OperationPOS About the POS OC-12c Uplink InterfaceConfiguring the POS OC-12c Uplink Interface Catalyst Default Configuration Initially Configuring the POS InterfaceParameter Configuration Command Default Value Line internal Automatic Reverting of Clock SourceIp-address subnet-mask Hdlc pppCustomizing the Configuration Additional ConfigurationsSetting the MTU Size Value j0 value sls0 value Configuring FramingConfiguring Sonet Overhead Sdh sonetConfiguring POS SPE Scrambling Scrambling is on by defaultScramble-atm Configuring Sonet Alarms Configuring Sonet Delay Triggers AlarmAlarm Description Triggers line path millisecond Verifying the POS ConfigurationLais pais plop prdi slof SlosRouter# show protocols pos 1/0/0 LOP = PLM-P Router# show controllers pos 2/0/0Router# show controller pos 2/0/0 detail Smdr About the ATM Uplink Interface About ATM Uplinks CatalystNo atm sonet stm-1 for OC-3 Configuring the ATM Uplink Interface CatalystConfiguration Overview No loopbackParameter Value Initially Configuring the ATM Uplink InterfaceNo atm clock internal Atm vc-per-vpConfiguring the Clock Source ATM interface or to STM-4 for the OC-12c interface Configuring Sonet FramingRouterconfig-if# atm sonet Stm-1Line msg line 64byte exp-msg Overhead c2 byte j0 bytesMsg line j1 16byte exp-msg Sls0 is part of the payload pointer byteConfiguring Loopback Creating a PVC Configuring Virtual CircuitsConfiguring CDP Configuring the Maximum VCs per VPName Mapping a Protocol Address to a PVCVpi vci aal-encap Ip-address atm-vc vcdVerifying the ATM Configuration Switch Router aSwitch Router B 5CB About Port Snooping Configuring Interfaces About Port SnoopingAbout the Snooping Source Port Configuring SnoopingRestrictions on Port Snooping About the Snooping Destination PortSource-port Direction receive transmit bothShow snoop Monitoring SnoopingShow snoop interface Destination-port78-6235-04, Cisco IOS Release 12.010W518