Configuration Guide for Cisco NCS 1001, IOS XR Release 25.x.x

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Configuration Guide for Cisco NCS 1001, IOS XR Release 25.x.x

Network troubleshooting commands

Updated: July 27, 2026

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This topic provides information about common management and OSPF routing issues with the commands used to check interface state, static routing, subnets, passive interfaces, and learned routes.

Troubleshooting must be performed by checking the status of the interfaces, subnets, static routing, and OSPF sections.

Problem

Command

Interfaces are in down state.

show interfaces MgmtEth rack/slot/instance/port

Route to default gateway is not defined.

show running-config

The design phase included incorrect IP addresses or subnets.

show running-config

Static routes were defined incorrectly and overwrite OSPF routes.

Compare the output of show ip route command with the show ospf routes command

The OSPF configuration does not include all the interfaces.

show running-config

The OSPF configuration sets certain interfaces to passive mode.

show running-config

Troubleshoot UDC port configurations

Troubleshoot UDC port configurations by clearing statistics and checking port attributes, port state, VLAN lists, and port counters.

Table 1. Feature History

Feature Name

Release

Description

Troubleshooting User Data Channel (UDC) Port Configurations

 Cisco IOS XR Release 7.8.1

The hw-module and show hw-module commands have been enhanced with additional keywords to improve the troubleshooting of issues on UDC ports. Apart from viewing the UDC port state, VLAN list, and port statistics, you can clear UDC port configurations and enable or disable configurations on each UDC port.

From Release 7.8.1, the hw-module eth-switch and show hw-module eth-switch commands provide options to troubleshoot UDC ports and view the current configuration.

Note

The hw-module eth-switch clear-stats command clears all the counters on the selected port and turns off the Clear-On-Read attribute. You can re-enable Clear-On-Read with the enable-clear-on-read attribute.

Procedure

1.

Clear the statistics configured for UDC port 1.

Example:


RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#hw-module eth-switch clear-stats port Rj45Udc1
RP/0/RP0/CPU0:ios(config)#commit
2.

Clear the statistics configured for all the ports.

Example:


RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#hw-module eth-switch clear-stats all
RP/0/RP0/CPU0:ios(config)#commit
3.

Display the configured attributes of the UDC ports.

Example:

RP/0/RP0/CPU0:ios#show hw-module eth-switch ports-attrs

This output shows the attributes of all the configured ports.

Thu Nov 10 13:24:16.932 CET
Ports Attributes:
Port SfpUdc3  # 0 (enable)      Link UP         Full-Duplex  9604 [1 Gbps] 6(1000BASE_X)     Clear-On-Read
Port SfpUdc2  # 4 (enable)      Link UP         Full-Duplex  9604 [1 Gbps] 6(1000BASE_X)     Clear-On-Read
Port SfpUdc1  # 8 (enable)      Link UP         Full-Duplex  9604 [1 Gbps] 6(1000BASE_X)     Clear-On-Read
Port Rj45Udc1 # 12 (enable)     Link DOWN       Half-Duplex  9600 [1 Gbps] 3(SGMII)     Clear-On-Read
Port Rj45Udc2 # 16 (enable)     Link DOWN       Half-Duplex  9600 [1 Gbps] 3(SGMII)     Clear-On-Read
Port Rj45Udc3 # 20 (enable)     Link DOWN       Half-Duplex  9600 [1 Gbps] 3(SGMII)     Clear-On-Read
Port CpuMgmt  # 24 (enable)     Link UP         Full-Duplex  1522 [1 Gbps] 6(1000BASE_X)      
Port          # 25 (enable)     Link UP         Full-Duplex  1522 [1 Gbps] 6(1000BASE_X)      
Port Rj45Mgmt # 26 (enable)     Link UP         Full-Duplex  1522 [1 Gbps] 3(SGMII)      
Port SfpMgmt  # 27 (enable)     Link DOWN       Half-Duplex  1522 [1 Gbps] 3(SGMII)

The command output displays the link state, duplex mode, maximum transmission unit, speed, interface type, and Clear-On-Read status for each configured port.
4.

Display the counters that are related to the CpuMgmt port.

Example:

RP/0/RP0/CPU0:ios#show hw-module eth-switch stats port CpuMgmt

This output displays the counter values for the CpuMgmt port.

Mon May 16 09:10:24.491 UTC

****************** START ******************
 PORT MAC COUNTERS - Test cmd [1] [Port:0x18]
  goodPktsSent          0
  goodPktsRcv           0
  ucPktsSent            17
  ucPktsRcv             2
  mcPktsSent            1489
  mcPktsRcv             0
  brdcPktsSent          349
  brdcPktsRcv           1
  goodOctetsSent        200863
  goodOctetsRcv         474
  pkts64Octets          614
  pkts65to127Octets     872
  pkts128to255Octets    86
  pkts256to511Octets    286
  pkts512to1023Octets   0
  pkts1024tomaxOoctets  0
  pkts1024to1518Octets  0

The command output displays MAC counter values, including packets, octets, and packet-size counters for the CpuMgmt port.
5.

Enable MAC counters Clear-On-Read for the Rj45Udc1 port.

Enabling or disabling MAC counters Clear-On-Read affects the corresponding port pairs: SfpUdc3 #0 and SfpUdc2 #4, and Rj45Udc1 #12 and Rj45Udc2 #16. Configuring this attribute on Rj45Udc1 #12 also affects Rj45Udc2 #16 and the other way around.

Example:

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#hw-module eth-switch port Rj45Udc1 enable-clear-on-read
RP/0/RP0/CPU0:ios(config)#commit
6.

Verify the hardware module Ethernet switch port attributes.

Example:

RP/0/RP0/CPU0:ios#show hw-module eth-switch ports-attrs
Ports Attributes:
Port SfpUdc3  # 0 (enable)      Link UP         Full-Duplex  9604 [1 Gbps] 6(1000BASE_X)      
Port SfpUdc2  # 4 (enable)      Link UP         Full-Duplex  9604 [1 Gbps] 6(1000BASE_X)      
Port SfpUdc1  # 8 (enable)      Link UP         Full-Duplex  9604 [1 Gbps] 6(1000BASE_X)      
Port Rj45Udc1 # 12 (enable)     Link UP      Half-Duplex  9600 [1 Gbps] 3(SGMII)     Clear-On-Read
Port Rj45Udc2 # 16 (enable)     Link UP      Half-Duplex  9600 [1 Gbps] 3(SGMII)     Clear-On-Read
Port Rj45Udc3 # 20 (enable)     Link UP         Full-Duplex  9600 [1 Gbps] 3(SGMII)      
Port CpuMgmt  # 24 (enable)     Link UP         Full-Duplex  1522 [1 Gbps] 6(1000BASE_X)      
Port          # 25 (enable)     Link UP         Full-Duplex  1522 [1 Gbps] 6(1000BASE_X)      
Port Rj45Mgmt # 26 (enable)     Link UP         Full-Duplex  1522 [100 Mbps] 3(SGMII)      
Port SfpMgmt  # 27 (enable)     Link DOWN       Half-Duplex  1522 [1 Gbps] 3(SGMII)

The command output shows whether Clear-On-Read is enabled for the expected UDC ports.

The UDC port statistics and Clear-On-Read behavior are updated and verified from the hardware module Ethernet switch command output.