Re: [secdir] SECDIR review of draft-ietf-bess-pta-flags-02.txt

[Eric C Rosen <[e-mail]>]

On 4/24/2016 7:29 PM, Christian Huitema wrote:
> We have thus two possible issues:
>
> 1) A router supports RFC 6514 but does not implement the extension
> mechanism.
> 2) A router supports the extension mechanism, but does not support the
> specific extension.

With regards to case 1, I don't think there's much to say.  A router 
that supports RFC 6514 but not the pta-flags draft will ignore all the 
flags except the one that is defined in RFC 6514.

Similarly, in case 2, a router that doesn't recognize a particular flag 
will ignore it.  However, I can add some text to the draft saying to 
ignore any bits you don't recognize.

If there are mechanisms that require the use of a particular extension, 
those mechanisms won't work properly with routers that don't support the 
necessary extension.  Applications that require such mechanisms either 
need to provide signaling to determine whether all involved routers 
support the necessary extension, or else they need to define procedures 
for interworking with routers that don't support the extension.  I could 
add some text stating this, but I don't think there's much more that can 
be said.