| < draft-thubert-6lo-rfc6775-update-00.txt | draft-thubert-6lo-rfc6775-update-01.txt > | |||
|---|---|---|---|---|
| 6lo P. Thubert, Ed. | 6lo P. Thubert, Ed. | |||
| Internet-Draft cisco | Internet-Draft cisco | |||
| Updates: 6775 (if approved) E. Nordmark | Updates: 6775 (if approved) E. Nordmark | |||
| Intended status: Standards Track Arista Networks | Intended status: Standards Track Arista Networks | |||
| Expires: November 5, 2016 S. Chakrabarti | Expires: April 29, 2017 S. Chakrabarti | |||
| Ericsson | Ericsson | |||
| May 4, 2016 | October 26, 2016 | |||
| An Update to 6LoWPAN ND | An Update to 6LoWPAN ND | |||
| draft-thubert-6lo-rfc6775-update-00 | draft-thubert-6lo-rfc6775-update-01 | |||
| Abstract | Abstract | |||
| This specification proposes an update to 6LoWPAN Neighbor Discovery, | This specification updates 6LoWPAN Neighbor Discovery (RFC6775), to | |||
| to clarify the role of the protocol as a registration technique, and | clarify the role of the protocol as a registration technique, | |||
| provide enhancements to the registration capabilities, in particular | simplify the registration operation in 6LoWPAN routers, and provide | |||
| for the registration to a backbone router for proxy ND operations. | enhancements to the registration capabilities, in particular for the | |||
| registration to a backbone router for proxy ND operations. | ||||
| Status of This Memo | Status of This Memo | |||
| This Internet-Draft is submitted in full conformance with the | This Internet-Draft is submitted in full conformance with the | |||
| provisions of BCP 78 and BCP 79. | provisions of BCP 78 and BCP 79. | |||
| Internet-Drafts are working documents of the Internet Engineering | Internet-Drafts are working documents of the Internet Engineering | |||
| Task Force (IETF). Note that other groups may also distribute | Task Force (IETF). Note that other groups may also distribute | |||
| working documents as Internet-Drafts. The list of current Internet- | working documents as Internet-Drafts. The list of current Internet- | |||
| Drafts is at http://datatracker.ietf.org/drafts/current/. | Drafts is at http://datatracker.ietf.org/drafts/current/. | |||
| Internet-Drafts are draft documents valid for a maximum of six months | Internet-Drafts are draft documents valid for a maximum of six months | |||
| and may be updated, replaced, or obsoleted by other documents at any | and may be updated, replaced, or obsoleted by other documents at any | |||
| time. It is inappropriate to use Internet-Drafts as reference | time. It is inappropriate to use Internet-Drafts as reference | |||
| material or to cite them other than as "work in progress." | material or to cite them other than as "work in progress." | |||
| This Internet-Draft will expire on November 5, 2016. | This Internet-Draft will expire on April 29, 2017. | |||
| Copyright Notice | Copyright Notice | |||
| Copyright (c) 2016 IETF Trust and the persons identified as the | Copyright (c) 2016 IETF Trust and the persons identified as the | |||
| document authors. All rights reserved. | document authors. All rights reserved. | |||
| This document is subject to BCP 78 and the IETF Trust's Legal | This document is subject to BCP 78 and the IETF Trust's Legal | |||
| Provisions Relating to IETF Documents | Provisions Relating to IETF Documents | |||
| (http://trustee.ietf.org/license-info) in effect on the date of | (http://trustee.ietf.org/license-info) in effect on the date of | |||
| publication of this document. Please review these documents | publication of this document. Please review these documents | |||
| skipping to change at page 2, line 13 ¶ | skipping to change at page 2, line 14 ¶ | |||
| include Simplified BSD License text as described in Section 4.e of | include Simplified BSD License text as described in Section 4.e of | |||
| the Trust Legal Provisions and are provided without warranty as | the Trust Legal Provisions and are provided without warranty as | |||
| described in the Simplified BSD License. | described in the Simplified BSD License. | |||
| Table of Contents | Table of Contents | |||
| 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 | 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 | |||
| 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 | 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 | |||
| 3. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 4 | 3. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 4 | |||
| 3.1. Extended Address Registration Option . . . . . . . . . . 4 | 3.1. Extended Address Registration Option . . . . . . . . . . 4 | |||
| 3.2. Link-local Scope and Consequences . . . . . . . . . . . . 5 | 3.2. Registering the Target Address . . . . . . . . . . . . . 5 | |||
| 4. Applicability and Requirements Served . . . . . . . . . . . . 6 | 3.3. Link-local Addresses and Registration . . . . . . . . . . 5 | |||
| 4. Applicability and Requirements Served . . . . . . . . . . . . 7 | ||||
| 5. The Enhanced Address Registration Option (EARO) . . . . . . . 7 | 5. The Enhanced Address Registration Option (EARO) . . . . . . . 7 | |||
| 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 | 6. Backward Compatibility . . . . . . . . . . . . . . . . . . . 11 | |||
| 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 | 6.1. Legacy 6LoWPAN Node . . . . . . . . . . . . . . . . . . . 11 | |||
| 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 | 6.2. Legacy 6LoWPAN Router . . . . . . . . . . . . . . . . . . 11 | |||
| 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 | 6.3. Legacy 6LoWPAN Border Router . . . . . . . . . . . . . . 12 | |||
| 9.1. Normative References . . . . . . . . . . . . . . . . . . 11 | 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 | |||
| 9.2. Informative References . . . . . . . . . . . . . . . . . 12 | 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 | |||
| 9.3. External Informative References . . . . . . . . . . . . . 15 | 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 | |||
| Appendix A. Requirements . . . . . . . . . . . . . . . . . . . . 15 | 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 | |||
| A.1. Requirements Related to Mobility . . . . . . . . . . . . 16 | 10.1. Normative References . . . . . . . . . . . . . . . . . . 13 | |||
| A.2. Requirements Related to Routing Protocols . . . . . . . . 16 | 10.2. Informative References . . . . . . . . . . . . . . . . . 14 | |||
| 10.3. External Informative References . . . . . . . . . . . . 16 | ||||
| Appendix A. Requirements . . . . . . . . . . . . . . . . . . . . 17 | ||||
| A.1. Requirements Related to Mobility . . . . . . . . . . . . 17 | ||||
| A.2. Requirements Related to Routing Protocols . . . . . . . . 17 | ||||
| A.3. Requirements Related to the Variety of Low-Power Link | A.3. Requirements Related to the Variety of Low-Power Link | |||
| types . . . . . . . . . . . . . . . . . . . . . . . . . . 17 | types . . . . . . . . . . . . . . . . . . . . . . . . . . 18 | |||
| A.4. Requirements Related to Proxy Operations . . . . . . . . 18 | A.4. Requirements Related to Proxy Operations . . . . . . . . 19 | |||
| A.5. Requirements Related to Security . . . . . . . . . . . . 18 | A.5. Requirements Related to Security . . . . . . . . . . . . 20 | |||
| A.6. Requirements Related to Scalability . . . . . . . . . . . 19 | A.6. Requirements Related to Scalability . . . . . . . . . . . 21 | |||
| Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 | Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 | |||
| 1. Introduction | 1. Introduction | |||
| The scope of this draft is an IPv6 Low Power Lossy Network (LLN), | The scope of this draft is an IPv6 Low Power Lossy Network (LLN), | |||
| which can be a simple star or a more complex mesh topology. The LLN | which can be a simple star or a more complex mesh topology. The LLN | |||
| may be anchored at an IPv6 Backbone Router (6BBR). The Backbone | may be anchored at an IPv6 Backbone Router (6BBR). The Backbone | |||
| Routers interconnect the LLNs over a Backbone Link and emulate that | Routers interconnect the LLNs over a Backbone Link and emulate that | |||
| the LLN nodes are present on the Backbone using proxy-ND operations. | the LLN nodes are present on the Backbone using proxy-ND operations. | |||
| IPv6 Neighbor Discovery (ND) Optimization for IPv6 over Low-Power | IPv6 Neighbor Discovery (ND) Optimization for IPv6 over Low-Power | |||
| skipping to change at page 3, line 31 ¶ | skipping to change at page 3, line 36 ¶ | |||
| Routing for Low-Power and Lossy Networks" [RFC7102] and | Routing for Low-Power and Lossy Networks" [RFC7102] and | |||
| [I-D.ietf-6tisch-terminology], as well as this additional | [I-D.ietf-6tisch-terminology], as well as this additional | |||
| terminology: | terminology: | |||
| Backbone This is an IPv6 transit link that interconnects 2 or more | Backbone This is an IPv6 transit link that interconnects 2 or more | |||
| Backbone Routers. It is expected to be deployed as a high | Backbone Routers. It is expected to be deployed as a high | |||
| speed backbone in order to federate a potentially large set of | speed backbone in order to federate a potentially large set of | |||
| LLNS. Also referred to as a LLN backbone or Backbone network. | LLNS. Also referred to as a LLN backbone or Backbone network. | |||
| Backbone Router An IPv6 router that federates the LLN using a | Backbone Router An IPv6 router that federates the LLN using a | |||
| Backbone link as a backbone. A BBR acts as a 6LoWPAN Border | Backbone link as a backbone. A 6BBR acts as a 6LoWPAN Border | |||
| Routers (6LBR) and an Energy Aware Default Router (NEAR). | Routers (6LBR) and an Energy Aware Default Router (NEAR). | |||
| Extended LLN This is the aggregation of multiple LLNs as defined in | Extended LLN This is the aggregation of multiple LLNs as defined in | |||
| [RFC4919], interconnected by a Backbone Link via Backbone | [RFC4919], interconnected by a Backbone Link via Backbone | |||
| Routers, and forming a single IPv6 MultiLink Subnet. | Routers, and forming a single IPv6 MultiLink Subnet. | |||
| Registration The process during which a wireless Node registers its | Registration The process during which a wireless Node registers its | |||
| address(es) with the Border Router so the 6BBR can proxy ND for | address(es) with the Border Router so the 6BBR can proxy ND for | |||
| it over the backbone. | it over the backbone. | |||
| skipping to change at page 4, line 20 ¶ | skipping to change at page 4, line 25 ¶ | |||
| the NS(ARO) is that of the Registering Node, which causes it to | the NS(ARO) is that of the Registering Node, which causes it to | |||
| attract the packets from the 6BBR to the Registered Node and | attract the packets from the 6BBR to the Registered Node and | |||
| route them over the LLN. | route them over the LLN. | |||
| Registered Address The address owned by the Registered Node node | Registered Address The address owned by the Registered Node node | |||
| that is being registered. | that is being registered. | |||
| 3. Updating RFC 6775 | 3. Updating RFC 6775 | |||
| The support of this specification is signaled in Router Advertisement | The support of this specification is signaled in Router Advertisement | |||
| (RA) messages by 6LoWPAN Router (6LR) (how: tbd). A Registering Node | (RA) messages by 6LoWPAN Router (6LR) (how: tbd). Support for this | |||
| that supports this specification will favor registering to a 6LR that | specification can also be inferred from the update of the ARO option | |||
| indicates support for this specification over that of [RFC6775]. | in the ND exchanges | |||
| . A Registering Node that supports this specification will favor | ||||
| registering to a 6LR that indicates support for this specification | ||||
| over that of [RFC6775]. | ||||
| 3.1. Extended Address Registration Option | 3.1. Extended Address Registration Option | |||
| This specification extends the Address Registration Option (ARO) used | This specification extends the Address Registration Option (ARO) used | |||
| for the process of address registration. The new ARO is referred to | for the process of address registration. The new ARO is referred to | |||
| as Extended ARO (EARO), and its semantics are modified as follows: | as Extended ARO (EARO), and its semantics are modified as follows: | |||
| The address that is being registered with a Neighbor Solicitation | The address that is being registered with a Neighbor Solicitation | |||
| (NS) with an EARO is now the Target Address, as opposed to the Source | (NS) with an EARO is now the Target Address, as opposed to the Source | |||
| Address as specified in [RFC6775]. This change enables a 6LBR to use | Address as specified in [RFC6775]. This change enables a 6LBR to use | |||
| skipping to change at page 5, line 5 ¶ | skipping to change at page 5, line 11 ¶ | |||
| Provable Temporary UID (PT-UID) as opposed to burn-in MAC address, | Provable Temporary UID (PT-UID) as opposed to burn-in MAC address, | |||
| the PT-UID providing a trusted anchor by the 6LR and 6LBR to protect | the PT-UID providing a trusted anchor by the 6LR and 6LBR to protect | |||
| the state associated to the node. | the state associated to the node. | |||
| The specification introduces a Transaction ID (TID) field in the | The specification introduces a Transaction ID (TID) field in the | |||
| EARO. The TID MUST be provided by a node that supports this | EARO. The TID MUST be provided by a node that supports this | |||
| specification and a new T flag MUST be set to indicate so. The T bit | specification and a new T flag MUST be set to indicate so. The T bit | |||
| can be used to determine whether the peer supports this | can be used to determine whether the peer supports this | |||
| specification. | specification. | |||
| 3.2. Link-local Scope and Consequences | 3.2. Registering the Target Address | |||
| The use of link-local addresses as source address for the | One of the requirements that this specification serves is the | |||
| registration, and the expectation for the scope of those addresses, | capability by a router such as a RPL root to proxy-register an | |||
| are clarified as follows: | address to a 6BBR on behalf of a 6LN, as discussed in Appendix A.4. | |||
| In order to serve that requirement, this specification changes the | ||||
| behaviour of the 6LN and the 6LR so that the Registered Address is | ||||
| found in the Target Address field of the NS and NA messages as | ||||
| opposed to the Source Address. | ||||
| A link is abstracted as a one-hop point-to-point communication | With this convention, a TLLA option would indicate the link-layer | |||
| medium. There is no need nor expectation that a link-local address | address of the 6LN that owns the address, whereas the SLLA Option in | |||
| is unique across the whole LLN. A 6LR assumes that the link-local | a NS message indicates that of the Registering Node, which can be the | |||
| address of a Registering Node is unique as long as the 6LR does not | owner device, or a proxy. | |||
| have a conflicting registration for that address. | ||||
| Since the Registering Node is the one that has reachability with the | ||||
| 6LR, and is the one expecting packets for the 6LN, it makes sense to | ||||
| maintain compatibility with [RFC6775], and it is REQUIRED that an | ||||
| SLLA Option is always placed in a registration NS(EARO) message. | ||||
| 3.3. Link-local Addresses and Registration | ||||
| Considering that LLN nodes are often not wired and may move, there is | ||||
| no guarantee that a link-local address stays unique between a | ||||
| potentially variable and unbounded set of neighboring nodes. | ||||
| Compared to [RFC6775], this specification only requires that a link- | ||||
| local address is unique from the perspective of the peering nodes. | ||||
| This simplifies the Duplicate Address Detection (DAD) for link-local | ||||
| addresses, and there is no DAR/DAC exchange between the 6LR and a | ||||
| 6LBR for link-local addresses. | ||||
| Additionally, [RFC6775] requires that a 6LoWPAN Node (6LN) uses an | ||||
| address being registered as the source of the registration message. | ||||
| This generates complexities in the 6LR to be able to cope with a | ||||
| potential duplication, in particular for global addresses. To | ||||
| simplify this, a 6LN and a 6LR that conform this specification always | ||||
| use link-local addresses as source and destination addresses for the | ||||
| registration NS/NA exchange. As a result, the registration is | ||||
| globally faster, and some of the complexity is removed. | ||||
| In more details: | ||||
| An exchange between two nodes using link-local addresses implies that | An exchange between two nodes using link-local addresses implies that | |||
| they are reachable over one hop and that at least one of the 2 nodes | they are reachable over one hop and that at least one of the 2 nodes | |||
| acts as a 6LR. A node MUST register a link-local address to a 6LR in | acts as a 6LR. A node MUST register a link-local address to a 6LR in | |||
| order to obtain link scope reachability from that 6LR beyond the | order to obtain reachability from that 6LR beyond the current | |||
| current exchange, and in particular to use it as Source Address to | exchange, and in particular to use the link-local address as source | |||
| register other addresses. | address to register other addresses, e.g. global addresses. If there | |||
| is no collision with an address previously registered to this 6LR by | ||||
| another 6LN, then, from the standpoint of this 6LR, this link-local | ||||
| address is unique and the registration is acceptable. Conversely, it | ||||
| may possibly happen that two different 6LRs expose a same link-local | ||||
| address but different link-layer addresses. In that case, a 6LN may | ||||
| only interact with one of the 6LR so as to avoid confusion in the 6LN | ||||
| neighbor cache. | ||||
| A consequence of this model is that the Duplicate Address Detection | The DAD process between the 6LR and a 6LoWPAN Border Router (6LBR), | |||
| (DAD) process between the 6LR and a 6LoWPAN Border Router (6LBR), | ||||
| which is based on a Duplicate Address Request (DAR) / Duplicate | which is based on a Duplicate Address Request (DAR) / Duplicate | |||
| Address Confirmation (DAC) exchange as described in [RFC6775], does | Address Confirmation (DAC) exchange as described in [RFC6775], does | |||
| not take place for link-local addresses. | not need to take place for link-local addresses. | |||
| It is desired that a 6LR does not need to modify its state associated | It is desired that a 6LR does not need to modify its state associated | |||
| to the Source Address of an NS(EARO) message. For that reason, when | to the Source Address of an NS(EARO) message. For that reason, when | |||
| possible, it is RECOMMENDED to use an address that is already | possible, it is RECOMMENDED to use an address that is already | |||
| registered with a 6LR as source for the NS(EARO) message. | registered with a 6LR | |||
| When a Registering Node does not yet have an already-registered | When registering to a 6LR that conforms this specification, a node | |||
| address, it MUST register a link-local address, using it as both the | MUST use a link-local address as the source address of the | |||
| Source and the Target Address of an NS(EARO) message. In that case, | registration, whatever the type of IPv6 address that is being | |||
| it is RECOMMENDED to use a link-local address that is (expected to | registered. That link-local Address MUST be either already | |||
| be) globally unique, e.g. derived from a burn-in MAC address. | registrered, or the address that is being registered. | |||
| When a Registering Node does not have an already-registered address, | ||||
| it MUST register a link-local address, using it as both the Source | ||||
| and the Target Address of an NS(EARO) message. In that case, it is | ||||
| RECOMMENDED to use a link-local address that is (expected to be) | ||||
| globally unique, e.g. derived from a burn-in MAC address. An EARO | ||||
| option in the response NA indicates that the 6LR supports this | ||||
| specification. | ||||
| Since there is no DAR/DAC exchange for link-local addresses, the 6LR | Since there is no DAR/DAC exchange for link-local addresses, the 6LR | |||
| may answer immediately to the registration of a link-local address, | may answer immediately to the registration of a link-local address, | |||
| based solely on its existing state and the Source Link-Layer Option | based solely on its existing state and the Source Link-Layer Option | |||
| that MUST be placed in the NS(EARO) message as required in [RFC6775]. | that MUST be placed in the NS(EARO) message as required in [RFC6775]. | |||
| A node must register its IPv6 Global Unicast IPv6 Addresses (GUA) to | A node needs to register its IPv6 Global Unicast IPv6 Addresses (GUA) | |||
| a 6LR in order to obtain a global reachability for these addresses | to a 6LR in order to obtain a global reachability for these addresses | |||
| via that 6LR. In particular a Registering NODE registering a GUA | via that 6LR. As opposed to a node that complies to [RFC6775], a | |||
| SHOULD NOT use that GUA as Source Address for the registration to a | Registering Node registering a GUA does use that GUA as Source | |||
| 6LR that conforms this specification. | Address for the registration to a 6LR that conforms this | |||
| specification. The DAR/DAC exchange MUST take place for non-link- | ||||
| What makes this model practical in existing LLNs, which can grow to | local addresses as prescribed by [RFC6775]. | |||
| large number of nodes, is that a subnet may encompass multiple links, | ||||
| which can be LLN links or can be backbone links that federate a | ||||
| number of LLN links, effectively forming a non-broadcast multi-access | ||||
| (NBMA) multi-link subnet (MLSN). | ||||
| 4. Applicability and Requirements Served | 4. Applicability and Requirements Served | |||
| This specification extends 6LoWPAN ND to sequence the registration | This specification extends 6LoWPAN ND to sequence the registration | |||
| and serves the requirements expressed Appendix A.1 by enabling the | and serves the requirements expressed Appendix A.1 by enabling the | |||
| mobility of devices from one LLN to the next based on the | mobility of devices from one LLN to the next based on the | |||
| complementary work in [I-D.ietf-6lo-backbone-router]. | complementary work in [I-D.ietf-6lo-backbone-router]. | |||
| In the context of the the TimeSlotted Channel Hopping (TSCH) mode of | In the context of the the TimeSlotted Channel Hopping (TSCH) mode of | |||
| [IEEE802154], the 6TiSCH architecture [I-D.ietf-6tisch-architecture] | [IEEE802154], the 6TiSCH architecture [I-D.ietf-6tisch-architecture] | |||
| skipping to change at page 9, line 10 ¶ | skipping to change at page 10, line 10 ¶ | |||
| Length: 2 | Length: 2 | |||
| Status: | Status: | |||
| +-------+-----------------------------------------------------------+ | +-------+-----------------------------------------------------------+ | |||
| | Value | Description | | | Value | Description | | |||
| +-------+-----------------------------------------------------------+ | +-------+-----------------------------------------------------------+ | |||
| | 0..2 | See [RFC6775]. Note that a Status of 1 "Duplicate | | | 0..2 | See [RFC6775]. Note that a Status of 1 "Duplicate | | |||
| | | Address" applies to the Registered Address. If the Source | | | | Address" applies to the Registered Address. If the Source | | |||
| | | Address differs from the Registered Address it conflicts | | | | Address conflicts with an existing registration, | | |||
| | | with an existing registration, "Invalid Source Address" | | | | "Duplicate Source Address" should be used instead | | |||
| | | should be used instead. | | ||||
| | | | | | | | | |||
| | 3 | Moved: The registration fails because it is not the | | | 3 | Moved: The registration fails because it is not the | | |||
| | | freshest. | | | | freshest | | |||
| | | | | | | | | |||
| | 4 | Removed: The binding state was removed. This may be | | | 4 | Removed: The binding state was removed. This may be | | |||
| | | placed in an asynchronous NS(ARO) message, or as the | | | | placed in an asynchronous NS(ARO) message, or as the | | |||
| | | rejection of a proxy registration to a Backbone Router. | | | | rejection of a proxy registration to a Backbone Router | | |||
| | | | | | | | | |||
| | 5 | Proof requested | | | 5 | Proof requested: The registering node is challenged for | | |||
| | | owning the registered address or for being an acceptable | | ||||
| | | proxy for the registration | | ||||
| | | | | | | | | |||
| | 6 | Invalid Source Address: The address used as source of the | | | 6 | Duplicate Source Address: The address used as source of | | |||
| | | NS(ARO) conflicts with an existing registration, or is | | | | the NS(ARO) conflicts with an existing registration. | | |||
| | | not usable on this link, e.g. it is not topologically | | ||||
| | | correct. | | ||||
| | | | | | | | | |||
| | 7 | Administrative Rejection: The address is reserved for | | | 7 | Administrative Rejection: The address being registered is | | |||
| | | another use by an administrative decision (e.g. placed in | | | | reserved for another use by an administrative decision | | |||
| | | a DHCPv6 pool). The Registering Node is requested to | | | | (e.g. placed in a DHCPv6 pool); The Registering Node is | | |||
| | | form a different address and retry. | | | | requested to form a different address and retry | | |||
| | | | | ||||
| | 8 | Invalid Registered Address: The address being registered | | ||||
| | | is not usable on this link, e.g. it is not topologically | | ||||
| | | correct | | ||||
| | | | | ||||
| | 9 | Invalid Source Address: The address used as source of the | | ||||
| | | NS(ARO) is not usable on this link, e.g. it is not | | ||||
| | | topologically correct | | ||||
| +-------+-----------------------------------------------------------+ | +-------+-----------------------------------------------------------+ | |||
| Table 1 | Table 1 | |||
| Reserved: This field is unused. It MUST be initialized to zero by | Reserved: This field is unused. It MUST be initialized to zero by | |||
| the sender and MUST be ignored by the receiver. | the sender and MUST be ignored by the receiver. | |||
| T: One bit flag. Set if the next octet is a used as a TID. | T: One bit flag. Set if the next octet is a used as a TID. | |||
| TID: 1-byte integer; a transaction id that is maintained by the node | TID: 1-byte integer; a transaction id that is maintained by the node | |||
| skipping to change at page 10, line 25 ¶ | skipping to change at page 11, line 33 ¶ | |||
| Removed: This status is expected in asynchronous messages from a | Removed: This status is expected in asynchronous messages from a | |||
| registrar (6LR, 6LBR, 6BBR) to indicate that the registration | registrar (6LR, 6LBR, 6BBR) to indicate that the registration | |||
| state is removed, for instance due to time out of a lifetime, or a | state is removed, for instance due to time out of a lifetime, or a | |||
| movement. It is used for instance by a 6BBR in a NA(ARO) message | movement. It is used for instance by a 6BBR in a NA(ARO) message | |||
| to indicate that the ownership of the proxy state on the backbone | to indicate that the ownership of the proxy state on the backbone | |||
| was transfered to another 6BBR, which is indicative of a movement | was transfered to another 6BBR, which is indicative of a movement | |||
| of the device. The receiver of the NA is the device that has | of the device. The receiver of the NA is the device that has | |||
| performed a registration that is now stale and it should clean up | performed a registration that is now stale and it should clean up | |||
| its state. | its state. | |||
| 6. Security Considerations | 6. Backward Compatibility | |||
| 6.1. Legacy 6LoWPAN Node | ||||
| A legacy 6LN will use the registered address as source and will not | ||||
| use an EARO option. In order to be backward compatible, an updated | ||||
| 6LR needs to accept that registration if it is valid per [RFC3972], | ||||
| and manage the binding cache accordingly. | ||||
| The main difference with [RFC3972] is that DAR/DAC exchange for DAD | ||||
| may be avoided for link-local addresses. Additionally, the 6LR | ||||
| SHOULD use an EARO in the reply, and may use all the status codes | ||||
| defined in this specification. | ||||
| 6.2. Legacy 6LoWPAN Router | ||||
| The first registration by a an updated 6LN is for a link-local | ||||
| address, using that link-local address as source. A legacy 6LN will | ||||
| not makes a difference and accept -or reject- that registration as if | ||||
| the 6LN was a legacy node. | ||||
| An updated 6LN will always use an EARO option in the registration NS | ||||
| message, whereas a legacy 6LN will always areply with an ARO option | ||||
| in the NA message. So from that first registration, the updated 6LN | ||||
| can figure whether the 6LR supports this specification or not. | ||||
| When facing a legacy 6LR, an updated 6LN may attempt to find an | ||||
| alternate 6LR that is updated. In order to be backward compatible, | ||||
| based on the discovery that a 6LR is legacy, the 6LN needs to | ||||
| fallback to legacy behaviour and source the packet with the | ||||
| registrered address. | ||||
| The main difference is that the updated 6LN SHOULD use an EARO in the | ||||
| request regardless of the type of 6LN, legacy or updated | ||||
| 6.3. Legacy 6LoWPAN Border Router | ||||
| With this specification, the DAR/DAC transports an EARO option as | ||||
| opposed to an ARO option. As described for the NS/NA exchange, | ||||
| devices that support this specification always use an EARO option and | ||||
| all the associated behaviour. | ||||
| 7. Security Considerations | ||||
| This specification expects that the link layer is sufficiently | This specification expects that the link layer is sufficiently | |||
| protected, either by means of physical or IP security for the | protected, either by means of physical or IP security for the | |||
| Backbone Link or MAC sublayer cryptography. In particular, it is | Backbone Link or MAC sublayer cryptography. In particular, it is | |||
| expected that the LLN MAC provides secure unicast to/from the | expected that the LLN MAC provides secure unicast to/from the | |||
| Backbone Router and secure Broadcast from the Backbone Router in a | Backbone Router and secure Broadcast from the Backbone Router in a | |||
| way that prevents tempering with or replaying the RA messages. | way that prevents tempering with or replaying the RA messages. | |||
| The use of EUI-64 for forming the Interface ID in the link-local | The use of EUI-64 for forming the Interface ID in the link-local | |||
| address prevents the usage of Secure ND ([RFC3971] and [RFC3972]) and | address prevents the usage of Secure ND ([RFC3971] and [RFC3972]) and | |||
| skipping to change at page 11, line 5 ¶ | skipping to change at page 13, line 5 ¶ | |||
| When the ownership of the OUID cannot be assessed, this specification | When the ownership of the OUID cannot be assessed, this specification | |||
| limits the cases where the OUID and the TID are multicasted, and | limits the cases where the OUID and the TID are multicasted, and | |||
| obfuscates them in responses to attempts to take over an address. | obfuscates them in responses to attempts to take over an address. | |||
| The LLN nodes depend on the 6LBR and the 6BBR for their operation. A | The LLN nodes depend on the 6LBR and the 6BBR for their operation. A | |||
| trust model must be put in place to ensure that the right devices are | trust model must be put in place to ensure that the right devices are | |||
| acting in these roles, so as to avoid threats such as black-holing, | acting in these roles, so as to avoid threats such as black-holing, | |||
| or bombing attack whereby an impersonated 6LBR would destroy state in | or bombing attack whereby an impersonated 6LBR would destroy state in | |||
| the network by using the "Removed" status code. | the network by using the "Removed" status code. | |||
| 7. IANA Considerations | 8. IANA Considerations | |||
| This document requires the following additions: | This document requires the following additions: | |||
| Address Registration Option Status Values Registry | Address Registration Option Status Values Registry | |||
| +--------+--------------------------+ | +--------+--------------------------+ | |||
| | Status | Description | | | Status | Description | | |||
| +--------+--------------------------+ | +--------+--------------------------+ | |||
| | 3 | Moved | | | 3 | Moved | | |||
| | | | | | | | | |||
| skipping to change at page 11, line 29 ¶ | skipping to change at page 13, line 29 ¶ | |||
| | | | | | | | | |||
| | 6 | Invalid Source Address | | | 6 | Invalid Source Address | | |||
| | | | | | | | | |||
| | 7 | Administrative Rejection | | | 7 | Administrative Rejection | | |||
| +--------+--------------------------+ | +--------+--------------------------+ | |||
| IANA is required to change the registry accordingly | IANA is required to change the registry accordingly | |||
| Table 2: New ARO Status values | Table 2: New ARO Status values | |||
| 8. Acknowledgments | 9. Acknowledgments | |||
| Kudos to Eric Levy-Abegnoli who designed the First Hop Security | Kudos to Eric Levy-Abegnoli who designed the First Hop Security | |||
| infrastructure at Cisco. | infrastructure at Cisco. | |||
| 9. References | 10. References | |||
| 9.1. Normative References | 10.1. Normative References | |||
| [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate | [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate | |||
| Requirement Levels", BCP 14, RFC 2119, | Requirement Levels", BCP 14, RFC 2119, | |||
| DOI 10.17487/RFC2119, March 1997, | DOI 10.17487/RFC2119, March 1997, | |||
| <http://www.rfc-editor.org/info/rfc2119>. | <http://www.rfc-editor.org/info/rfc2119>. | |||
| [RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD) | [RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD) | |||
| for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006, | for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006, | |||
| <http://www.rfc-editor.org/info/rfc4429>. | <http://www.rfc-editor.org/info/rfc4429>. | |||
| skipping to change at page 12, line 23 ¶ | skipping to change at page 14, line 23 ¶ | |||
| Low-Power and Lossy Networks", RFC 6550, | Low-Power and Lossy Networks", RFC 6550, | |||
| DOI 10.17487/RFC6550, March 2012, | DOI 10.17487/RFC6550, March 2012, | |||
| <http://www.rfc-editor.org/info/rfc6550>. | <http://www.rfc-editor.org/info/rfc6550>. | |||
| [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. | [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. | |||
| Bormann, "Neighbor Discovery Optimization for IPv6 over | Bormann, "Neighbor Discovery Optimization for IPv6 over | |||
| Low-Power Wireless Personal Area Networks (6LoWPANs)", | Low-Power Wireless Personal Area Networks (6LoWPANs)", | |||
| RFC 6775, DOI 10.17487/RFC6775, November 2012, | RFC 6775, DOI 10.17487/RFC6775, November 2012, | |||
| <http://www.rfc-editor.org/info/rfc6775>. | <http://www.rfc-editor.org/info/rfc6775>. | |||
| 9.2. Informative References | 10.2. Informative References | |||
| [I-D.chakrabarti-nordmark-6man-efficient-nd] | [I-D.chakrabarti-nordmark-6man-efficient-nd] | |||
| Chakrabarti, S., Nordmark, E., Thubert, P., and M. | Chakrabarti, S., Nordmark, E., Thubert, P., and M. | |||
| Wasserman, "IPv6 Neighbor Discovery Optimizations for | Wasserman, "IPv6 Neighbor Discovery Optimizations for | |||
| Wired and Wireless Networks", draft-chakrabarti-nordmark- | Wired and Wireless Networks", draft-chakrabarti-nordmark- | |||
| 6man-efficient-nd-07 (work in progress), February 2015. | 6man-efficient-nd-07 (work in progress), February 2015. | |||
| [I-D.delcarpio-6lo-wlanah] | [I-D.delcarpio-6lo-wlanah] | |||
| Vega, L., Robles, I., and R. Morabito, "IPv6 over | Vega, L., Robles, I., and R. Morabito, "IPv6 over | |||
| 802.11ah", draft-delcarpio-6lo-wlanah-01 (work in | 802.11ah", draft-delcarpio-6lo-wlanah-01 (work in | |||
| progress), October 2015. | progress), October 2015. | |||
| [I-D.ietf-6lo-6lobac] | [I-D.ietf-6lo-6lobac] | |||
| Lynn, K., Martocci, J., Neilson, C., and S. Donaldson, | Lynn, K., Martocci, J., Neilson, C., and S. Donaldson, | |||
| "Transmission of IPv6 over MS/TP Networks", draft-ietf- | "Transmission of IPv6 over MS/TP Networks", draft-ietf- | |||
| 6lo-6lobac-04 (work in progress), February 2016. | 6lo-6lobac-05 (work in progress), June 2016. | |||
| [I-D.ietf-6lo-backbone-router] | [I-D.ietf-6lo-backbone-router] | |||
| Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo- | Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo- | |||
| backbone-router-01 (work in progress), March 2016. | backbone-router-02 (work in progress), September 2016. | |||
| [I-D.ietf-6lo-dect-ule] | [I-D.ietf-6lo-dect-ule] | |||
| Mariager, P., Petersen, J., Shelby, Z., Logt, M., and D. | Mariager, P., Petersen, J., Shelby, Z., Logt, M., and D. | |||
| Barthel, "Transmission of IPv6 Packets over DECT Ultra Low | Barthel, "Transmission of IPv6 Packets over DECT Ultra Low | |||
| Energy", draft-ietf-6lo-dect-ule-04 (work in progress), | Energy", draft-ietf-6lo-dect-ule-07 (work in progress), | |||
| February 2016. | October 2016. | |||
| [I-D.ietf-6lo-nfc] | [I-D.ietf-6lo-nfc] | |||
| Hong, Y. and J. Youn, "Transmission of IPv6 Packets over | Choi, Y., Youn, J., and Y. Hong, "Transmission of IPv6 | |||
| Near Field Communication", draft-ietf-6lo-nfc-03 (work in | Packets over Near Field Communication", draft-ietf-6lo- | |||
| progress), March 2016. | nfc-05 (work in progress), October 2016. | |||
| [I-D.ietf-6man-rs-refresh] | ||||
| Nordmark, E., Yourtchenko, A., and S. Krishnan, "IPv6 | ||||
| Neighbor Discovery Optional RS/RA Refresh", draft-ietf- | ||||
| 6man-rs-refresh-01 (work in progress), March 2016. | ||||
| [I-D.ietf-6tisch-architecture] | [I-D.ietf-6tisch-architecture] | |||
| Thubert, P., "An Architecture for IPv6 over the TSCH mode | Thubert, P., "An Architecture for IPv6 over the TSCH mode | |||
| of IEEE 802.15.4", draft-ietf-6tisch-architecture-09 (work | of IEEE 802.15.4", draft-ietf-6tisch-architecture-10 (work | |||
| in progress), November 2015. | in progress), June 2016. | |||
| [I-D.ietf-6tisch-terminology] | [I-D.ietf-6tisch-terminology] | |||
| Palattella, M., Thubert, P., Watteyne, T., and Q. Wang, | Palattella, M., Thubert, P., Watteyne, T., and Q. Wang, | |||
| "Terminology in IPv6 over the TSCH mode of IEEE | "Terminology in IPv6 over the TSCH mode of IEEE | |||
| 802.15.4e", draft-ietf-6tisch-terminology-07 (work in | 802.15.4e", draft-ietf-6tisch-terminology-07 (work in | |||
| progress), March 2016. | progress), March 2016. | |||
| [I-D.ietf-bier-architecture] | [I-D.ietf-bier-architecture] | |||
| Wijnands, I., Rosen, E., Dolganow, A., Przygienda, A., and | Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and | |||
| S. Aldrin, "Multicast using Bit Index Explicit | S. Aldrin, "Multicast using Bit Index Explicit | |||
| Replication", draft-ietf-bier-architecture-03 (work in | Replication", draft-ietf-bier-architecture-04 (work in | |||
| progress), January 2016. | progress), July 2016. | |||
| [I-D.ietf-ipv6-multilink-subnets] | [I-D.ietf-ipv6-multilink-subnets] | |||
| Thaler, D. and C. Huitema, "Multi-link Subnet Support in | Thaler, D. and C. Huitema, "Multi-link Subnet Support in | |||
| IPv6", draft-ietf-ipv6-multilink-subnets-00 (work in | IPv6", draft-ietf-ipv6-multilink-subnets-00 (work in | |||
| progress), July 2002. | progress), July 2002. | |||
| [I-D.nordmark-6man-dad-approaches] | ||||
| Nordmark, E., "Possible approaches to make DAD more robust | ||||
| and/or efficient", draft-nordmark-6man-dad-approaches-02 | ||||
| (work in progress), October 2015. | ||||
| [I-D.popa-6lo-6loplc-ipv6-over-ieee19012-networks] | [I-D.popa-6lo-6loplc-ipv6-over-ieee19012-networks] | |||
| Popa, D. and J. Hui, "6LoPLC: Transmission of IPv6 Packets | Popa, D. and J. Hui, "6LoPLC: Transmission of IPv6 Packets | |||
| over IEEE 1901.2 Narrowband Powerline Communication | over IEEE 1901.2 Narrowband Powerline Communication | |||
| Networks", draft-popa-6lo-6loplc-ipv6-over- | Networks", draft-popa-6lo-6loplc-ipv6-over- | |||
| ieee19012-networks-00 (work in progress), March 2014. | ieee19012-networks-00 (work in progress), March 2014. | |||
| [I-D.sarikaya-6lo-ap-nd] | [I-D.sarikaya-6lo-ap-nd] | |||
| Sarikaya, B. and P. Thubert, "Address Protected Neighbor | Sethi, M., Thubert, P., and B. Sarikaya, "Address | |||
| Discovery for Low-power and Lossy Networks", draft- | Protected Neighbor Discovery for Low-power and Lossy | |||
| sarikaya-6lo-ap-nd-02 (work in progress), March 2016. | Networks", draft-sarikaya-6lo-ap-nd-04 (work in progress), | |||
| August 2016. | ||||
| [I-D.vyncke-6man-mcast-not-efficient] | ||||
| Vyncke, E., Thubert, P., Levy-Abegnoli, E., and A. | ||||
| Yourtchenko, "Why Network-Layer Multicast is Not Always | ||||
| Efficient At Datalink Layer", draft-vyncke-6man-mcast-not- | ||||
| efficient-01 (work in progress), February 2014. | ||||
| [RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener | [RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener | |||
| Discovery Version 2 (MLDv2) for IPv6", RFC 3810, | Discovery Version 2 (MLDv2) for IPv6", RFC 3810, | |||
| DOI 10.17487/RFC3810, June 2004, | DOI 10.17487/RFC3810, June 2004, | |||
| <http://www.rfc-editor.org/info/rfc3810>. | <http://www.rfc-editor.org/info/rfc3810>. | |||
| [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, | [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, | |||
| "SEcure Neighbor Discovery (SEND)", RFC 3971, | "SEcure Neighbor Discovery (SEND)", RFC 3971, | |||
| DOI 10.17487/RFC3971, March 2005, | DOI 10.17487/RFC3971, March 2005, | |||
| <http://www.rfc-editor.org/info/rfc3971>. | <http://www.rfc-editor.org/info/rfc3971>. | |||
| skipping to change at page 15, line 5 ¶ | skipping to change at page 16, line 35 ¶ | |||
| Interface Identifiers with IPv6 Stateless Address | Interface Identifiers with IPv6 Stateless Address | |||
| Autoconfiguration (SLAAC)", RFC 7217, | Autoconfiguration (SLAAC)", RFC 7217, | |||
| DOI 10.17487/RFC7217, April 2014, | DOI 10.17487/RFC7217, April 2014, | |||
| <http://www.rfc-editor.org/info/rfc7217>. | <http://www.rfc-editor.org/info/rfc7217>. | |||
| [RFC7428] Brandt, A. and J. Buron, "Transmission of IPv6 Packets | [RFC7428] Brandt, A. and J. Buron, "Transmission of IPv6 Packets | |||
| over ITU-T G.9959 Networks", RFC 7428, | over ITU-T G.9959 Networks", RFC 7428, | |||
| DOI 10.17487/RFC7428, February 2015, | DOI 10.17487/RFC7428, February 2015, | |||
| <http://www.rfc-editor.org/info/rfc7428>. | <http://www.rfc-editor.org/info/rfc7428>. | |||
| [RFC7559] Krishnan, S., Anipko, D., and D. Thaler, "Packet-Loss | ||||
| Resiliency for Router Solicitations", RFC 7559, | ||||
| DOI 10.17487/RFC7559, May 2015, | ||||
| <http://www.rfc-editor.org/info/rfc7559>. | ||||
| [RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B., | [RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B., | |||
| Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low | Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low | |||
| Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015, | Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015, | |||
| <http://www.rfc-editor.org/info/rfc7668>. | <http://www.rfc-editor.org/info/rfc7668>. | |||
| [RFC7772] Yourtchenko, A. and L. Colitti, "Reducing Energy | 10.3. External Informative References | |||
| Consumption of Router Advertisements", BCP 202, RFC 7772, | ||||
| DOI 10.17487/RFC7772, February 2016, | ||||
| <http://www.rfc-editor.org/info/rfc7772>. | ||||
| 9.3. External Informative References | ||||
| [IEEE80211] | [IEEE80211] | |||
| IEEE standard for Information Technology, "IEEE Standard | IEEE standard for Information Technology, "IEEE Standard | |||
| for Information technology-- Telecommunications and | for Information technology-- Telecommunications and | |||
| information exchange between systems Local and | information exchange between systems Local and | |||
| metropolitan area networks-- Specific requirements Part | metropolitan area networks-- Specific requirements Part | |||
| 11: Wireless LAN Medium Access Control (MAC) and Physical | 11: Wireless LAN Medium Access Control (MAC) and Physical | |||
| Layer (PHY) Specifications". | Layer (PHY) Specifications". | |||
| [IEEE802151] | [IEEE802151] | |||
| skipping to change at page 16, line 8 ¶ | skipping to change at page 17, line 29 ¶ | |||
| Appendix A. Requirements | Appendix A. Requirements | |||
| This section lists requirements that were discussed at 6lo for an | This section lists requirements that were discussed at 6lo for an | |||
| update to 6LoWPAN ND. This specification meets most of them, but | update to 6LoWPAN ND. This specification meets most of them, but | |||
| those listed in Appendix A.5 which are deferred to a different | those listed in Appendix A.5 which are deferred to a different | |||
| specification such as [I-D.sarikaya-6lo-ap-nd]. | specification such as [I-D.sarikaya-6lo-ap-nd]. | |||
| A.1. Requirements Related to Mobility | A.1. Requirements Related to Mobility | |||
| Due to the unstable nature of LLN links, even in a LLN of immobile | Due to the unstable nature of LLN links, even in a LLN of immobile | |||
| nodes a 6LoWPAN Node may change its point of attachment to a 6LR, say | nodes a 6LN may change its point of attachment to a 6LR, say 6LR-a, | |||
| 6LR-a, and may not be able to notify 6LR-a. Consequently, 6LR-a may | and may not be able to notify 6LR-a. Consequently, 6LR-a may still | |||
| still attract traffic that it cannot deliver any more. When links to | attract traffic that it cannot deliver any more. When links to a 6LR | |||
| a 6LR change state, there is thus a need to identify stale states in | change state, there is thus a need to identify stale states in a 6LR | |||
| a 6LR and restore reachability in a timely fashion. | and restore reachability in a timely fashion. | |||
| Req1.1: Upon a change of point of attachment, connectivity via a new | Req1.1: Upon a change of point of attachment, connectivity via a new | |||
| 6LR MUST be restored timely without the need to de-register from the | 6LR MUST be restored timely without the need to de-register from the | |||
| previous 6LR. | previous 6LR. | |||
| Req1.2: For that purpose, the protocol MUST enable to differentiate | Req1.2: For that purpose, the protocol MUST enable to differentiate | |||
| between multiple registrations from one 6LoWPAN Node and | between multiple registrations from one 6LoWPAN Node and | |||
| registrations from different 6LoWPAN Nodes claiming the same address. | registrations from different 6LoWPAN Nodes claiming the same address. | |||
| Req1.3: Stale states MUST be cleaned up in 6LRs. | Req1.3: Stale states MUST be cleaned up in 6LRs. | |||
| Req1.4: A 6LoWPAN Node SHOULD also be capable to register its Address | Req1.4: A 6LoWPAN Node SHOULD also be capable to register its Address | |||
| to multiple 6LRs, and this, concurrently. | to multiple 6LRs, and this, concurrently. | |||
| A.2. Requirements Related to Routing Protocols | A.2. Requirements Related to Routing Protocols | |||
| The point of attachment of a 6LoWPAN Node may be a 6LR in an LLN | The point of attachment of a 6LN may be a 6LR in an LLN mesh. IPv6 | |||
| mesh. IPv6 routing in a LLN can be based on RPL, which is the | routing in a LLN can be based on RPL, which is the routing protocol | |||
| routing protocol that was defined at the IETF for this particular | that was defined at the IETF for this particular purpose. Other | |||
| purpose. Other routing protocols than RPL are also considered by | routing protocols than RPL are also considered by Standard Defining | |||
| Standard Defining Organizations (SDO) on the basis of the expected | Organizations (SDO) on the basis of the expected network | |||
| network characteristics. It is required that a 6LoWPAN Node attached | characteristics. It is required that a 6LoWPAN Node attached via ND | |||
| via ND to a 6LR would need to participate in the selected routing | to a 6LR would need to participate in the selected routing protocol | |||
| protocol to obtain reachability via the 6LR. | to obtain reachability via the 6LR. | |||
| Next to the 6LBR unicast address registered by ND, other addresses | Next to the 6LBR unicast address registered by ND, other addresses | |||
| including multicast addresses are needed as well. For example a | including multicast addresses are needed as well. For example a | |||
| routing protocol often uses a multicast address to register changes | routing protocol often uses a multicast address to register changes | |||
| to established paths. ND needs to register such a multicast address | to established paths. ND needs to register such a multicast address | |||
| to enable routing concurrently with discovery. | to enable routing concurrently with discovery. | |||
| Multicast is needed for groups. Groups MAY be formed by device type | Multicast is needed for groups. Groups MAY be formed by device type | |||
| (e.g. routers, street lamps), location (Geography, RPL sub-tree), or | (e.g. routers, street lamps), location (Geography, RPL sub-tree), or | |||
| both. | both. | |||
| End of changes. 44 change blocks. | ||||
| 136 lines changed or deleted | 210 lines changed or added | |||
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