Subject: [Roll] DAP projection vs. Useofrplinfo

From: "Pascal Thubert (pthubert)" <[email-masked]>
Date: Mon, 5 Oct 2020 16:53:51 +0000

Dear all

I added text in the Github repo of DAO projection to clarify the encapsulation in case of a projected route.
The text says
"
*  This draft conforms the principles of [USEofRPLinfo] with regards
      to packet forwarding and encapsulation along a Track.

      -  In that case, the Track is the DODAG, the Track Ingress is a
         RAL, and the Track Egress is the Root.

      -  If the Track Ingress is the originator of the packet and the
         Track Egress is the destination of the packet, there is no need
         for an encapsulation.

      -  But since the RPL Instance a Local one, the final destination
         in the outer header of a packet sent along a Track MUST be the
         Track Egress.  So the Track Ingress MUST encapsulate its own
         traffic if the destination is reached over the Track via the
         Track Egress but is located beyond it (this is a MAY for a
         Global Instance in [USEofRPLinfo])

      -  Traffic that is injected in the Track is processed as external,
         so it is subject to encapsulation.
"

You'll note that a MAY (in RAL to Int) in fig 7 of useofrplinfo becomes a MUST, because we need to signal the Track Egress.

+---------------------+--------------+------------+----------------+
   | Interaction between |   Use Case   |IPv6-in-IPv6|IPv6-in-IPv6 dst|
   +---------------------+--------------+------------+----------------+
   |                     |  RAL to root |    No      |      N/A       |
   +                     +--------------+------------+----------------+
   |     Leaf - Root     |  root to RAL |    No      |      N/A       |
   +                     +--------------+------------+----------------+
   |                     | root to RUL  |   must     |       6LR      |
   +                     +--------------+------------+----------------+
   |                     | RUL to root  |   must     |       root     |
   +---------------------+--------------+------------+----------------+
   |                     |  RAL to Int  |   may      |      root      |
   +                     +--------------+------------+----------------+
   |   Leaf - Internet   |  Int to RAL  |   must     |      RAL (tgt) |
   +                     +--------------+------------+----------------+
   |                     |  RUL to Int  |   must     |       root     |
   +                     +--------------+------------+----------------+
   |                     |  Int to RUL  |   must     |       6LR      |
   +---------------------+--------------+------------+----------------+
   |                     |  RAL to RAL  |    No      |      N/A       |
   |  Leaf - Leaf        +--------------+------------+----------------+
   |                     |  RAL to RUL  |    No(up)  |      N/A       |
   |                     +              +------------+----------------+
   |                     |              | must(down) |      6LR       |
   |                     +--------------+------------+----------------+
   |                     |  RUL to RAL  |   must(up) |      root      |
   |                     |              +------------+----------------+
   |                     |              | must(down) |      RAL       |
   |                     +--------------+------------+----------------+
   |                     |  RUL to RUL  |   must(up) |      root      |
   |                     |              +------------+----------------+
   |                     |              | must(down) |      6LR       |
   |---------------------+--------------+------------+----------------+

It's because the text in use of RPL info assumes that the RAL injects traffic in a global instance. Should we add a note for that case?
The MAY is a MUST in a local instance.

Keep safe.

Pascal

[https://www.cisco.com/c/dam/m/en_us/signaturetool/images/logo/Cisco_Logo_no_TM_Indigo_Blue-RGB_43px.png]
Pascal Thubert
PRINCIPAL ENGINEER.ENGINEERING
[email-masked]<mailto:[email-masked]>
Tel: +33 49 723 2634
 cisco.com
Cisco Systems, Inc.
45 All Des Ormes Regus Centre
BP1200
06250 MOUGINS CEDEX
France
[http://www.cisco.com/assets/swa/img/thinkbeforeyouprint.gif]
Think before you print.
This email may contain confidential and privileged material for the sole use of the intended recipient. Any review, use, distribution or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive for the recipient), please contact the sender by reply email and delete all copies of this message.
Please click here<http://www.cisco.com/c/en/us/about/legal/terms-sale-software-license-agreement/company-registration-information.html> for Company Registration Information.