DELETE Interface

[kokencisco]

Hi,

I created a sub-interface but now I want to delete it. I type "router#(config)delete interface serial3/0.1" but if I type "sh ip int brief" now, appear

"Serial3/0.1 unassigned YES manual deleted down"

How Can I delete really this interface?

THANKS

[Kevin Dorrell]

I have never seen the delete interface form - I have always used no interface Serial 3/0.1.

It is true that some types of subinterface cannot be fully deleted. They stay as zombies and they only go away when you reload the router. But usually you get a warning message about that when you delete them. Furthermore, if you re-create them before the reload, they get some of their old config back.

Does the sub-interface appear in a show run?

Kevin Dorrell

Luxembourg

[thisisshanky]

Do you have an alias setup for the no command? Just reload your router after you remove the sub interface with the "no int s3/0.1" and that should take care of it ?

[Richard Burts]

It may help to understand the reason that these subintefaces do not go completely away. The basic thing to understand is that the running config is not just a text file with config statements (which is what we get when we do show running-config) but it is a binary data structure in memory. When you create a subinteface certain elements in the binary data structure are initialized. When you delete the subinterface (using the no interface command) these elements are still in the data structure. When you do a show running-config they do not show up because the config knows that they are not being used. But show ip interface brief does show them because the config element is still present. This also explains why you can not change the subinterfaces (for example if you create a Frame Relay subinteface as multipoint and then attempt to change it to point to point you can not change it. Even if you delete the subinterface and attempt to create it over again as the other type you get an error message about not able to change the interface.)

As mentioned in previous responses the only way to make the subinterface really go away is to reload the router.

HTH

Rick

[kokencisco]

Thanks a lot to all people that had answer me! If I do SHO RUN the sub-interface don't appear, if I do SH IP INT BRIEF also appear! Now thanks to RBURTS I know because happen this!!

Bye