Configuration Guide for Cisco NCS 1014, IOS XR Releases 26.x.x

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Configuration Guide for Cisco NCS 1014, IOS XR Releases 26.x.x

MAC address snooping on client ports

Updated: June 18, 2026

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This section explains how MAC address snooping features help identify connected neighbors on client ports and overcome networks where LLDP cannot be used.

A MAC address snooping on client ports feature is a network monitoring capability that:

  • learns the MAC address of the connected neighbor on 1.2T cards at client ports

  • enables ARP snooping across all client ports through CLI, and

  • helps overcome environments where LLDP cannot be used for neighbor discovery.

This feature overcomes the limitation, where 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.

  • 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

Use this task to configure MAC address or ARP snoop on slice in muxponder slice mode.

Procedure

Run the 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 command.

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/nxr0 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

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 0/1/0/2/1 
Mon Mar 16 19:40:37.434 UTC
Operational data for interface HundredGigECtrlr0/1/0/2/1:
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

View neighbor MAC address

Use this task to view the neighbor's physical address after enabling MAC address or ARP snoop.

MAC address snoop output is enabled after ARP packets are received on the respective 100G client.

Procedure

Run the show controllers hundredGigEctrlr R/S/I/P command.

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 0/1/0/2/1 
Mon Mar 16 19:41:08.047 UTC
Operational data for interface HundredGigECtrlr0/1/0/2/1:
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