Ines, Michael,
Please find my remarks about draft-robles-roll-useofrplinfo-00 below.
Thomas
----
TW> overall comments
TW> - this is a super important informational draft, which
TW> clears up a lot of questions
TW> - I think it would be very useful to have more example
TW> packets. We are building such information for the upcoming 6TiSCH
TW> plugtest, so I can help there.
TW> - After this is done I would recommend to ask explicitly for
TW> reviewers. Robert Cragie should be
TW> on the list of people to ask; he has provided very useful info
TW> during our discussions.
ROLL Working Group M.I. Robles
Internet-Draft Ericsson
Intended status: Informational M. Richardson
Expires: December 29, 2015 SSW
June 27, 2015
When to use RFC 6553, 6554 and IPv6-in-IPv6
draft-robles-roll-useofrplinfo-00
Abstract
This document states different cases where RFC 6553, RFC 6554 and
IPv6-in-IPv6 encapsulation is required to set the bases to help
defining the compression of RPL routing information in LLN
environments.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology and Requirements Language . . . . . . . . . . . . 2
3. Sample/reference topology . . . . . . . . . . . . . . . . . . 3
4. Example flow from leaf to root . . . . . . . . . . . . . . . 4
4.1. Non-storing . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Storing . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Example flow from leaf to Internet . . . . . . . . . . . . . 6
5.1. Non-storing . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. Storing . . . . . . . . . . . . . . . . . . . . . . . . . 7
6. Example flow from leaf to leaf . . . . . . . . . . . . . . . 7
6.1. Traditional storing . . . . . . . . . . . . . . . . . . . 7
6.2. Traditional non-storing . . . . . . . . . . . . . . . . . 7
6.3. P2P non-storing . . . . . . . . . . . . . . . . . . . . . 7
7. Example flow from Internet to leaf . . . . . . . . . . . . . 7
7.1. Storing . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.2. Non-storing . . . . . . . . . . . . . . . . . . . . . . . 7
8. Example flow from root to leaf . . . . . . . . . . . . . . . 7
8.1. Storing . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.2. Non-storing . . . . . . . . . . . . . . . . . . . . . . . 7
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
10. Security Considerations . . . . . . . . . . . . . . . . . . . 8
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
12.1. Normative References . . . . . . . . . . . . . . . . . . 8
12.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
RPL [RFC6550] defines RPL Option to transmit routing information.
RFC 6553 [RFC6553] defines how to transmit in a Hop-By-Hop Option RPL
Information,such as information to avoid and detect loops. RFC 6554
[RFC6554] defines the use of Extension header for Source Routing.
TW> this is a bit confusing to me. AFAICT:
TW> - RFC6550 defines the RPL routing protocol
TW> - RFC6553 defines the "RPL option", carried within the IPv6 Hop-by-Hop
TW> header to quickly identify inconsistencies in the routing topology
TW> - RFC6554 defines the "RPL Source Route Header", an IPv6 Extension
Header to deliver datagrams within a RPL routing domain
Several discussions in
TW> the
ROLL/6lo/6tisch
TW> 6tisch -> 6TiSCH
Mailing Lists took place
focusing in the definition
TW> of
how to compress RPL Information in
constrained environment. ROLL Virtual Interim Meeting (02-2015)
concluded that there is a need to define how to use RFC 6553, RFC6554
TW> you have to decide whether you use "RFC 123" or "RFC123". I would
TW> recommend you replace this by a hyperlink
and tunneling (IP-in-IP)
TW> I would say "and IP-in-IP encapsulation"
to be able to set the correct environment
for compression.
2. Terminology and Requirements Language
TW> you're actually not using any of this language in the draft.
TW> if you keep it that way, and since the draft is informational
TW> I would recommend to remove this section
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Terminology defined in [RFC7102]
3. Sample/reference topology
In a typical topology we found
TW> "we found" reads strange. What about "A RPL network is composed of
TW> ...[6LR,6LBR]... logically organized in a DODAG structure".
6LBR (6LoWPAN Border Router), 6lR
TW> 6LR
(6LoWPAN Router) and 6LN (6LoWPAN Node) as leaf connected in a DODAG
(Destination Oriented Directed Acyclic Graph). Between these
entities messages such as DIS, DIO and DAO are transmitted. RPL
defines the RPL Control message as an ICMPv6 information message with
a Type of 155.
TW> RPL defines the RPL Control message, a new ICMPv6 message with
TW> Type 155. DIS, DIO and DAO messages are all RPL Control messages
TW> but with different Code values.
RPL supports two modes of Downward traffic: Storing,
it is fully stateful or Non-Storing it is fully source routed. Any
given RPL Instance is either storing or non-storing.
TW> please specify that a RPL Instance is either fully storing or fully
TW> non-storing, i.e. a RPL Instance with a combination of storing and
TW> non-storing nodes is not supported
+--------------+
| Upper Layers |
| |
+--------------+
| RPL |
| |
+--------------+
| ICMPv6 |
| |
+--------------+
| IPv6 |
| |
+--------------+
| 6LoWPAN |
| |
+--------------+
| PHY-MAC |
| |
+--------------+
Figure 1: RPL Stack
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+---------+
+---+Internet |
| +---------+
|
+----+--+
|DODAG |
+---------+Root +----------+
| |6LBR | |
| +----+--+ |
| | |
| | |
| | |
+-----+-+ +--+---+ +--+---+
|6LR | | | | |
+-----+ | | | | |
| | | | | | +------+
| +-----+-+ +-+----+ +-+----+ |
| | | | |
| | | | |
| | | | |
+-+---+ +-+---+ +--+--+ +- --+ +---+-+
|Leaf | | | | | | | | |
|6LN | | | | | | | | |
+-----+ +-----+ +-----+ +----+ +-----+
Figure 2: A reference RPL Topology
TW> I would add a "." at end of each caption
In different scenarios the use of RFC 6553, RFC 6554 and tunneling
can take place:
TW> I would say that a combination of RFC6553, RFC6554 and IP-in-IP
TW> encapsulation is used for the following traffic flows:
-Flow from leaf to root
TW> remove newlines?
-Flow from leaf to Internet
-Flow from leaf to leaf
-Flow from Internet to leaf
-Flow from leaf to root
TW> duplicate
4. Example flow from leaf to root
A leaf node generates DAO and DIS messages and in general does not
accept them.
TW> what do you mean by "accept"?
Additionally, this kind of nodes
TW> node
accepts DIO messages,
but in general do
TW> does
not generate them. (In inconsistency A leaf node
generates DIO with infinite rank, to fix it).
TW> A -> a
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4.1. Non-storing
In non-storing
TW> mode
in this case
TW> remove "in this case"
the leaf node uses Hop-By-Hop option (RFC
6553) to indicate the routing information to send messages to the
DODAG root, this message is going to be analyzed in each node until
arrive the DODAG root.
RFC 6554 was created to strictly send information between RPL routers
in the same RPL routing domain. How it would be in 6554?
TW> I assume a "TODO" missing before last sentence?
TBD: Tunneling is necessary in case that there is information to send
outside RPL Domain and other cases?
+------+
| |
| 6LBR |
| |
+---+--+
|
| LoWPAN_HC
| Route= 6LN-6LR-6LBR
^ |
| +---+-+
| | |
| | 6LR |
| | |
| +--+--+
| | LoWPAN_HC
| | Route= 6LN-6LR-6LBR
| |
+ |
+--+--+
| 6LN |
| |
| |
+-----+
Figure 3: From leaf to Root - Non-Storing Mode
TW> I don't fully understand what message this figure conveys
TW> I would use A B and C to name the nodes, and write their role
TW> next to them
4.2. Storing
IP6 6553{X,Y] ?ipip payload.
TW> something's wrong
In storing mode is suitable the use of
RFC 6553 to send RPL Information through HBH field checking the
routing table to find out where to send the message.
TW> I don't understand "checking the routing table to find out where
TW> to send the message"
It may include
IP-in-IP encapsulation to transmit information not related with the
RPL domain.
TW> I would expand this info
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+------+
| |
| 6LBR |
| |
+---+--+
|
| LoWPAN_HC
| 0x63|HBH Data
^ |
| +---+-+
| | |
| | 6LR | 6LR check in routing table
| | |
| +--+--+
| | LoWPAN_HC
| | 0x63|HBH Data
| |
+ |
+--+--+
| 6LN |
| |
| |
+-----+
Figure 4: From leaf to Root - Storing Mode
5. Example flow from leaf to Internet
5.1. Non-storing
In this case the IP-in-IP encapsulation should take place to send
information not related to the RPL domain inside of the RPL domain.
RPL information from RFC 6553 should not go out to Internet. The
router sould
TW> typo
take this information out before send the packet to
Internet. The HBH Option is going to be analyzed in each node to the
root.
TW> illustrate this with a fig?
Related to RFC 6554 the Source Header route is added and removed by
DODAG root. However, RFC 6554 was created to strictly send
information between RPL routers in the same RPL routing domain. How
it would be in 6554?
TW> this paragraph relates to down traffic, right? The name of the section
TW> is "from leaf to Internet"
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5.2. Storing
In storing the information of RFC 6553 should take away by DODAG root
before go to Internet.
TW> but as well in non-storing, no?
6. Example flow from leaf to leaf
can leafs insert appropriate headers, without ipip? In [RFC6550] RPL
allows a simple one-hop P2P optimization for both storing and non-
storing networks. A node may send a P2P packet destined to a one-hop
neighbor direclty
TW> typo
to that node. Section 9 in [RFC6550].
TW> I would say that IP-in-IP is not needed in this case
6.1. Traditional storing
TW> why "Traditional"?
The route go through an ancestor that knows the route to the
destination, using HBH [RFC6553] to carry RPL Information.
6.2. Traditional non-storing
The route go through the DODAG root, using source routing [RFC6554].
6.3. P2P non-storing
(p2p storing? TBD)
7. Example flow from Internet to leaf
A DODAG root do not add routing extension to incoming packets, it
instead uses tunneling.
7.1. Storing
DODAG root adds the HBH header [RFC6553] and send the packet downward
to the destination.
7.2. Non-storing
DODAG root is going to add the source route header [RFC6554]
8. Example flow from root to leaf
8.1. Storing
DODAG root adds the HBH header [RFC6553] and send the packet downward
to the destination.
8.2. Non-storing
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DODAG root is going to add the source route header [RFC6554]
9. IANA Considerations
There are no IANA considerations related to this document.
10. Security Considerations
TBD.
TW> I would replace TBD by TODO, per usual covention
11. Acknowledgements
TW> typo
This work is partially funded by the FP7 Marie Curie Initial Training
Network (ITN) METRICS project (grant agreement No. 607728)
12. References
12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R.,
Levis, P., Pister, K., Struik, R., Vasseur, JP., and R.
Alexander, "RPL: IPv6 Routing Protocol for Low-Power and
Lossy Networks", RFC 6550, March 2012.
[RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low-
Power and Lossy Networks (RPL) Option for Carrying RPL
Information in Data-Plane Datagrams", RFC 6553, March
2012.
[RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6
Routing Header for Source Routes with the Routing Protocol
for Low-Power and Lossy Networks (RPL)", RFC 6554, March
2012.
12.2. Informative References
[RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and
Lossy Networks", RFC 7102, January 2014.
Authors' Addresses
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Maria Ines Robles
Ericsson
Hirsalantie 11
Jorvas 02420
Finland
Email: [email protected]
Michael C. Richardson
Sandelman Software Works
470 Dawson Avenue
Ottawa, ON K1Z 5V7
CA
Email: [email protected]
URI: http://www.sandelman.ca/
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