Re: [secdir] secdir review of draft-ietf-isis-genapp

["Les Ginsberg (ginsberg)" <[e-mail]>]

Radia -

The use of "D" and "S" is copied from RFCs 4971/5305. The initials were
not further identified there and we used identical text in describing
them. (That's my excuse anyway)

As a point of information:

"S" - flooding "Scope"
"D" - Indicates the TLV has been leaked "Down" from Level2 to level1

The choice of the letters "I" and "V" was arbitrary.

   Les

> -----Original Message-----
> From: Radia Perlman [mailto:[e-mail]]
> Sent: Monday, August 09, 2010 2:58 PM
> To: [e-mail]; [e-mail];
> [e-mail]
> Subject: secdir review of draft-ietf-isis-genapp
> 
> This document is about using the reliable flooding mechanism of IS-IS
> to advertise information for applications unrelated to IS-IS in a way
> that doesn't use up "T" values in the TLV encoding.
> 
> So, since it's just syntax, there really aren't any security
> considerations.
> 
> It would have been nice if the authors explained what "V" "I" "D" and
> "S" mean in the context of the flags, as in, what word is "V" the
> first letter of, what word is "I" the first letter of...
> 
> Unless I missed it in the spec, the authors just give rules like:
> 
>                  D bit (0x02): When the GENINFO TLV is leaked from
>                  level-2 to level-1, the D bit MUST be set. Otherwise
>                  this bit MUST be clear. GENINFO TLVs with the D bit
> set
>                  MUST NOT be leaked from level-1 to level-2. This is
to
>                  prevent TLV looping.
> 
>                  I bit (0x04): When the I bit is set the 4 octet IPv4
>                  address associated with the application immediately
>                  follows the Application ID.
> 
> Radia