The Cisco Nexus 3550-F Fusion (formerly ExaLINK Fusion) incorporates many in-built diagnostics functions that can be used to monitor the device.

Sensors and monitors


The state of the power supplies in the Nexus 3550-F can be shown using show power-supply:

admin@N3550-F> show power-supply
Power supply 0
Manufacturer : EMERSON
Model        : DS460
Input        : 243.0 V  0.3 A
Output       : 12.2 V  3.8 A
Temperature  : 23.5 C (ambient)  34.0 C (internal)

Power supply 1
Manufacturer : EMERSON
Model        : DS460
Input        : 240.5 V  0.3 A
Output       : 12.2 V  5.0 A
Temperature  : 28.0 C (ambient)  44.2 C (internal)

It is also possible to show the current power on many of the internal sensors within the device. This can be done with the show power command:

admin@N3550-F> show power
             Voltage  Current
             -------  -------
Line card A  12.2 V    1.1 A
Line card B  12.3 V    1.5 A
Line card C  12.3 V    1.1 A
Module X     12.3 V    3.3 A
Module Y     12.3 V    0.0 A


The show temperature command can be used to show the temperature of various internal modules within the Nexus 3550-F.

admin@N3550-F> show temperature
Crosspoint   41.3 C  40.4 C  36.1 C  39.5 C
Line card A  35.6 C
Line card B  32.4 C
Line card C  33.9 C
Mainboard    29.6 C  27.2 C
Module X     36.0 C  45.0 C


The show fan-speed command shows the speed of the four fans in the Nexus 3550-F. These fans are individually monitored and controlled.

admin@N3550-F> show fan-speed
       Fan speed
Fan 0  8160
Fan 1  8040
Fan 2  8160
Fan 3  8160

Configuring a minimum fan speed


This feature requires version 1.15.0 or later

The Nexus 3550-F will regulate the fans to keep all system components below nominal temperatures. A minimum fan speed can be set if it is desired to keep some components of the Nexus 3550-F running cooler than the system would otherwise regulate them to. This is set as follows:

admin@N3550-F> configure fan-speed minimum 18000
Minimum fan speed set to 18000 RPM

To clear this condition:

admin@N3550-F> configure no fan-speed minimum
Minimum fan speed cleared

Viewing local logs

The system log can be viewed from the Nexus 3550-F command line, by using the following command:

show log

By default this will show all the entries that have priority of notice or higher, and have a system log identifier of exalinkd or switchd. The command accepts various parameters that allow the filters to be adjusted. Below are some examples of how to apply the filters.

To show messages with priority error or higher:

show log level error

Valid priority levels are:

  • emergency
  • alert
  • critical
  • error
  • warning
  • info
  • debug

To show messages with a syslog identifier of systemd or exalinkd:

show log systemd exalinkd

To show the last 20 messages from all syslog identifiers of level debug and higher:

show log all level debug last 20

To show the first five messages:

show log reverse last 5

To filter the normal output for entries that contain the word authenticated:

show log contains authenticated

Remote logging

The Nexus 3550-F supports remote logging using the syslog protocol. To configure remote logging, use the remote-logging command. The first step is to configure a remote target for log messages. Both TCP and UDP modes of syslog are supported. As an example, to log all error messages using UDP to a host at, use the command:

admin@N3550-F> configure remote-logging target udp all err
Remote logging configuration updated

Multiple targets can be configured using this command. Ports other than the default of 514 can also be specified, for example:

admin@N3550-F> configure remote-logging target udp all err
Remote logging configuration updated
admin@N3550-F> configure remote-logging target tcp all all
Remote logging configuration updated
admin@N3550-F> configure remote-logging target udp all debug
Remote logging configuration updated

To remove all remote logging targets use the no form of the remote logging command:

admin@N3550-F> configure no remote-logging
Reset remote-logging configuration

Remote logging can be globally enabled or disabled using the enable or disable command:

admin@N3550-F> configure remote-logging enable
Remote logging enabled

To view all of the current remote logging targets as well as the global state, use the show remote-logging command:

admin@N3550-F> configure show remote-logging
Type Address            Facility Level
---- ------------------ -------- -----
udp       all      err
udp       all      all
udp all      debug

remote-logging is enabled

Power failure

The management processor and interface in the Nexus 3550-F will keep running for several seconds after the power has been completely removed from the device. This allows for the message that a power failure event has occurred to be sent to the remote logging server. The following entries can be expected in the logs when power is removed:

Jul  2 01:41:45 EXALINK-FUSION kernel: [74253.339458] Power fail event detected
Jul  2 01:41:45 EXALINK-FUSION exalinkd[542]: exalink: Power fail event detected
Jul  2 01:41:45 EXALINK-FUSION exalinkd[542]: exalinkd: Shutting down on power fail event
Jul  2 01:41:45 EXALINK-FUSION exalinkd[542]: system: Rebooting in 5 seconds

If SNMP traps are enabled, a SNMP notification will also be sent.


Note that if power is removed and restored quickly, the management processor will automatically reboot the device in order to ensure all hardware has been properly re-initialized.

Non-Volatile Log

The Nexus 3550-F contains a small log of specific events that is non-volatile, ie a log that is not cleared on system reboot. This log includes the following events:

  • Power fail
  • User reboot
  • Firmware update
  • Tamper events, ie lid removal

The show nvlog command can be used to display this log, for example:

admin@N3550-F> sh nvlog
2017-02-22T23:56:10 reset-reason *system warm_sw
2017-02-23T03:59:39 exalinkd *system powerfail
2017-02-23T03:59:39 system *system reboot
2017-02-23T03:59:57 reset-reason *system cold
2017-02-23T04:06:14 system *system reboot
2017-02-23T04:06:14 exalinkd *system powerfail
2017-02-23T06:18:18 exalink_hw *system tamper 2017-02-23T05:16:13
2017-03-29T01:13:45 update_manager admin update_file exalink_fusion_1.6.0.tar

Debug dump

It is possible to generate a compressed file containing a large amount of useful information showing the state of the Nexus 3550-F. This can be sent to Cisco TAC to aid in resolving any issues.


This file contains version and config information, hardware status, byte/packet counters etc.
The dump file does not contain payload data from any packets received by the device.

To generate the dump file:

admin@N3550-F> debug dump
Debug data written to debug/debug_info_20160112T172853.tar.gz

This tarball can then be retrieved by sftp or tftp, for example:

$ sftp admin@
admin@'s password:
sftp> get debug/debug_info_20160112T172853.tar.gz

This page was last updated on Apr-06-2021.