Capwap Mailing List: Issue 180: Inconsistency of Session ID length

[Pat Calhoun (pacalhou) (pcalhoun]

All,

Yong Zhang brought up the following to my attention on draft -12. I have
created issue 180 to track this. I consider this a necessary change
since it will impact interoperability. I wonder if we could make this
change post IESG Review.

> 
> 3.  Does Session ID just take 4 bytes space?
> 
> 4.6.36.  Session ID
> 
>    The Session ID message element value contains a randomly generated
>    unsigned 32-bit integer.
> 
>       0                   1                   2                   3
>       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                           Session ID                          |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                           Session ID                          |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                           Session ID                          |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |                           Session ID                          |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
> 
>    Type:   35 for Session ID
> 
>    Length:   32
> 
>    Session ID:   A 32-bit unsigned integer used as a random session
>       identifier

The text should read 32 bytes, not 32 bits. That said, looking at the
draft, section 12.2 claims that the Session ID is really 64 bits. So I
am going to change it to 32 bytes, and change section 12.2 to 128 bits.

PatC