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New Member

Delete Sub-Interfaces ?

What command should I use to delete subinterfaces that are no longer required?



Re: Delete Sub-Interfaces ?

no int s1/0.10

will delete the int.

It will still show up in show ip int brief as well as other show outputs. This will be cleared out of the system (after deletion) once you reboot the router.


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Re: Delete Sub-Interfaces ?


you can delete the subinterfaces with

Router(config)#no interface Serial0.1

Be aware however, that the subinterface will be still there in software in the state deleted (check with "show ip interface brief"). To get totally rid of the subinterface on a router you need to reboot the router.

Hope this helps! Please rate all posts.

Regards, Martin

New Member

Re: Delete Sub-Interfaces ?

So I guess there is no way to delete it completely without a router reload.

Hall of Fame Super Silver

Re: Delete Sub-Interfaces ?


The reason that the subinterface remains is that the running config is not a text file in which you can remove the line about the subinterface, but is a binary data structure. When you configure the subinterface a part of the binary data structure is initialized for the subinterface. When you delete the subinterface that part of the data structure is still there. This is also the reason that you can not dynamically change the type of subinterface (from multipoint to point-to-point).

I have been told that there is a workaround if you really want the old subinterface to completely go away. If you change the interface encapsulation from frame relay to hdlc the subinterface may be completely removed (along with all the other subinterfaces that have been configured on that interface). Usually that is more drastic than it is worth. So baasically you should wait till there is reason to reload the router and then the subinterface will go away.