Configuration Guide for Cisco NCS 1004, IOS XR Release 25.x.x

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Configuration Guide for Cisco NCS 1004, IOS XR Release 25.x.x

MAC address snooping on client ports

Updated: July 31, 2026

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This section explains MAC address snooping on client ports for Cisco NCS 1004 controllers and describes feature behavior, supported controller context, and configuration considerations.

A MAC address snooping feature is a network discovery method that

  • enables learning the MAC address of the neighbor connected to client ports,

  • allows ARP snooping to be enabled on all client ports, and

  • supports MAC address learning through CLI for Cisco NCS 1004 controllers.

MAC address snooping on client ports details

This feature overcomes the limitation that LLDP (Link Layer Discovery Protocol) cannot be enabled in some networks.

Limitations

  • When you enable or disable MAC address snooping on any slice, few packets are dropped during configuration.

  • An open config interface for enabling or disabling MAC address snooping is not supported.

  • SNMP MIB is not supported for the MAC address attribute.

Note

When you enable MAC address snooping on client ports, it overrides LLDP.

Configure MAC address snooping on client ports

Enable MAC address or ARP snooping to enhance security and traffic monitoring on client ports in Muxponder mode.
Follow these steps to configure and verify MAC address or ARP snooping on client ports in muxponder mode:

Procedure

1.

Run the configure hw-module location location mxponder-slice slice-number client-rate 100GE trunk-rate 600G { 100G | 150G | 200G | 250G | 300G | 350G | 400G | 450G | 500G | 550G | 600G } arp-snoop to configure MAC address or ARP snoop on slice in muxponder slice mode.

Example:

This is a sample in which, MAC address or ARP snoop is configured on the client ports of slice 0 in muxponder slice mode.


RP/0/RP0/CPU0:ios#configure
Mon Mar 16 19:30:33.933 UTC
RP/0/RP0/CPU0:ios(config)#hw-module location 0/3 mxponder-slice 0
RP/0/RP0/CPU0:ios(config-hwmod-mxp)#client-rate 100GE
RP/0/RP0/CPU0:ios(config-hwmod-mxp)#trunk-rate 600G
RP/0/RP0/CPU0:ios(config-hwmod-mxp)#arp-snoop
RP/0/RP0/CPU0:ios(config-hwmod-mxp)#commit
Mon Mar 16 19:30:52.636 UTC
RP/0/RP0/CPU0:ios(config-hwmod-mxp)#end

This is a sample in which, MAC address or ARP snoop is configured in muxponder mode.


RP/0/RP0/CPU0:ios#configure 
Mon Mar 16 19:08:17.154 UTC
RP/0/RP0/CPU0:ios(config)#hw-module location 0/1 mxponder arp-snoop 
RP/0/RP0/CPU0:ios(config)#commit
2.

Run the show controllers hundredGigECtrlr command to verify the configuration.

Example:

This sample shows the output of show controllers hundredGigEctrlr command, before configuring MAC address or ARP snoop on client ports.


RP/0/RP0/CPU0:ios#show controllers hundredGigECtrlr 0/1/0/2 
Mon Mar 16 19:40:37.434 UTC
Operational data for interface HundredGigECtrlr0/1/0/2:

State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Disabled
    AINS Soak: None
      Total Duration: 0 hour(s) 0 minute(s)
      Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
    Laser Squelch: Disabled

Phy:
    Media type: Not known

Autonegotiation disabled.

Operational values:
    Speed: 100Gbps
    Duplex: Full Duplex
    Flowcontrol: None
    Loopback: None (or external)
    BER monitoring:
        Not supported
    Holdoff Time: 0ms

MAC address or ARP snooping is successfully configured on the specified client ports. The device now monitors and filters traffic as intended.

View neighbor address on client ports

Ensure that the neighbor device's MAC address is correctly detected on client ports.

You can view the neighbor's physical address after enabling MAC address or ARP snoop using the following command. MAC address snoop output is enabled after ARP packets are received on the respective 100G client.

Before you begin

MAC address snooping or ARP snooping must be configured on the client ports.

Follow these steps to view the neighbor's physical MAC address on client ports:

Procedure

Run the show controllers hundredGigECtrlr R/S/I/P command to view the neighbor's physical address on the client port.

Example:

This sample shows the neighbor's MAC address after configuring MAC address or ARP snoop on client ports.


RP/0/RP0/CPU0:ios#show controllers hundredGigECtrlr 0/1/0/2 
Mon Mar 16 19:41:08.047 UTC
Operational data for interface HundredGigECtrlr0/1/0/2:

State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Disabled
    AINS Soak: None
      Total Duration: 0 hour(s) 0 minute(s)
      Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
    Laser Squelch: Disabled
    Neighbor Address:
    0010.9400.5502

Phy:
    Media type: Not known

Autonegotiation disabled.

Operational values:
    Speed: 100Gbps
    Duplex: Full Duplex
    Flowcontrol: None

The neighbor's physical MAC address is displayed in the Neighbor Address field of the command output.