Re: [Roll] [roll] #5: DODAG

["Julien Abeille (jabeille)" <jabeille at cisco.com>]

Hi Phil,

> -----Original Message-----
> From: Philip Levis [mailto:pal at cs.stanford.edu] 
> Sent: lundi 9 novembre 2009 18:12
> To: Julien Abeille (jabeille)
> Cc: Tim Winter; ROLL WG
> Subject: Re: [Roll] [roll] #5: DODAG
> 
> 
> On Nov 9, 2009, at 2:11 AM, Julien Abeille (jabeille) wrote:
> 
> > Hi Tim,
> >
> > My question is: are there DAGs that are not DODAGs in RPL? 
> My feeling 
> > is no. Hence I would suppress the DODAG instead of turning 
> all "DAG" 
> > into "DODAG".
> > Best,
> > Julien
> 
> I disagree -- Directed Acyclic Graph is a very well defined 
> term in graph theory. We shouldn't redefine it. A DODAG is a 
> particular kind of DAG, where there is one and only one node 
> which has only incoming edges. We could maybe come up with a 
> better term than DODAG, but DAG definitely isn't it. It will 
> confuse readers tremendously.
Sorry, did not want to hurt graph theory specialists among IETF draft
readers. 

Seriously, what is confusing is to have DAGs and DODAGs everywhere in
the draft.
An instance is not as far as I understand a DAG. An instance is multiple
DODAGs. Hence either we use only DAG everywhere, or DODAG everywhere, no
mention of DAG. Thoughts?

Best,
Julien

> 
> Phil
>