what is the story on if_index allocation ?

[Petri Helenius]

Luigi Rizzo wrote:

>Can someone explain what is the goal ? Reuse a number if an
>interface has the same name of a previously existing one and
>the index is free ? And does it make sense, anyways, or
>we could just simplify that code and just reuse the first
>available entry in ifindex_table[] ?
>  
>
The optimal course of action (from management software point of view) is 
to retain as static ifName to ifIndex mapping. If the index changes for 
the same interface, you're supposed to have lower sysUpTime than on 
previous query.

Pete