According to Cisco IOS documentation, show subsys command displays the subsystem information which doesn't tell much. Is it basically a feature list for particular IOS image similar to one in Cisco Feature Navigator? What is the practical usage of show subsys command?

Few examples with c1841-spservicesk9-mz.124-22.T.bin can be seen below:

c1841#show subsys name bfd*
Name                Class     Version   
bfd                 Protocol    1.000.001     
bfd_registry        Registry    1.000.001     
c1841#show subsys name tcl 
Name                Class     Version   
tcl                 Library     2.000.001     

1 Answer 1


They are software component versions. Unless you're Cisco, the information is 99% meaningless.

  • Thanks for response! Cisco has probably some internal documentation which maps those software components seen in show subsys output and their versions to features seen in Cisco Feature Navigator and actual CLI commands?
    – Martin
    May 19, 2015 at 10:54

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