Subject: [Roll] The D and DODAGID fields inside a DAO

From: Mukul Goyal <[email-masked]>
Date: Thu, 5 Aug 2010 23:31:47 -0500 (CDT)

I guess I dont understand the purpose of the D and DODAGID fields inside a DAO.

The D field indicates if the RPLInstanceID value inside the DAO is local. But, isn't that information contained in the RPLInstanceID value itself?

Also, the DODAGID field is to be included only if the RPLInstanceID value is local. But, in that case, the DODAGID value can be identified by examining the D bit inside the local RPLInstanceID and the source/destination IPv6 address of the packet.

Thanks
Mukul

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From: Matteo Paris <[email-masked]>
Date: Fri, 6 Aug 2010 11:03:29 -0400

Hi Mukul,

RPL-11 section 6.4.1 says: "The 'D' flag indicates that the DODAGID 
field is present.  This flag MUST be set when a local RPLInstanceID 
is used."

This makes sense for storing mode.  But in non-storing mode, we 
should not require the 'D' flag to be set, because the DODAGID is the 
IP destination of the packet.  I brought this up previously here:

http://www.ietf.org/mail-archive/web/roll/current/msg05119.html

Pascal felt the 'D' flag should be required to be set even in 
non-storing mode, and that the redundant DODAGID should be compressed 
out by some yet-to-be-specified mechanism.  I think unsetting the 'D' 
flag is a good mechanism ;-)

I'd like to solicit WG input:

(a) Leave the text as is.
(b) Change the text to read "This flag MUST be set when a local 
RPLInstanceID is used in a storing mode of operation."

Thanks,
Matteo

At 11:31 PM -0500 8/5/10, Mukul Goyal wrote:
>The D field indicates if the RPLInstanceID value inside the DAO is 
>local. But, isn't that information contained in the RPLInstanceID 
>value itself?
>
>Also, the DODAGID field is to be included only if the RPLInstanceID 
>value is local. But, in that case, the DODAGID value can be 
>identified by examining the D bit inside the local RPLInstanceID and 
>the source/destination IPv6 address of the packet.
>
>Thanks
>Mukul
>
>_______________________________________________
>Roll mailing list
>[email-masked]
>https://www.ietf.org/mailman/listinfo/roll

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From: Mukul Goyal <[email-masked]>
Date: Fri, 6 Aug 2010 20:40:32 -0500 (CDT)

Hi Matteo

I think I prefer option b.

Thanks
Mukul

----- Original Message -----
From: "Matteo Paris" <[email-masked]>
To: "Mukul Goyal" <[email-masked]>, "roll" <[email-masked]>
Sent: Friday, August 6, 2010 10:03:29 AM
Subject: Re: [Roll] The D and  DODAGID fields inside a DAO

Hi Mukul,

Thanks,
Matteo