Transmission of IPv6 Packets over PLC Networks
draft-hou-6lo-plc-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
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|---|---|---|---|
| Authors | Jianqiang Hou , Yong-Geun Hong , Xiaojun Tang | ||
| Last updated | 2017-03-12 | ||
| Replaced by | draft-ietf-6lo-plc, RFC 9354 | ||
| RFC stream | (None) | ||
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draft-hou-6lo-plc-00
6Lo Working Group J. Hou
Internet-Draft Huawei Technologies
Intended Status: Standards Track Y-G. Hong
Expires: September 11, 2017 ETRI
X. Tang
SGEPRI
March 10, 2017
Transmission of IPv6 Packets over PLC Networks
draft-hou-6lo-plc-00
Abstract
Power Line Communication (PLC), namely using the electric-power lines
for indoor and outdoor communications, has been widely applied to
support Advanced Metering Infrastructure (AMI), especially the smart
meters for electricity. With the inherent advantage of existing
electricity infrastructure, PLC is expanding deployments all over the
world, indicating the potential demand of IPv6 for future
applications. As part of this technology, Narrowband PLC (NBPLC) is
focused on the low-bandwidth and low-power scenarios, including
current standards such as IEEE 1901.2 and ITU-T G.9903. This
document describes how IPv6 packets are transported over constrained
PLC networks.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 11, 2017.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Notation and Terminology . . . . . . . . . . . . 3
3. Overview of PLC . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Protocol Stack . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Addressing Modes . . . . . . . . . . . . . . . . . . . . . 5
3.3. Maximum Transmission Unit . . . . . . . . . . . . . . . . 6
4. Specification of IPv6 over Narrowband PLC . . . . . . . . . . 6
4.1. IEEE 1901.2 . . . . . . . . . . . . . . . . . . . . . . . 6
4.1.1. Stateless Address Autoconfiguration . . . . . . . . . 6
4.1.2. IPv6 Link Local Address . . . . . . . . . . . . . . . 7
4.1.3. Unicast and Multicast Address Mapping . . . . . . . . 7
4.1.4. Header Compression . . . . . . . . . . . . . . . . . . 8
4.1.5. Fragmentation and Reassembly . . . . . . . . . . . . . 9
4.2. ITU-T G.9903 . . . . . . . . . . . . . . . . . . . . . . . 9
4.2.1. Stateless Address Autoconfiguration . . . . . . . . . 9
4.2.2. IPv6 Link Local Address . . . . . . . . . . . . . . . 9
4.2.3. Unicast and Multicast Address Mapping . . . . . . . . 10
4.2.4. Header Compression . . . . . . . . . . . . . . . . . . 11
4.2.5. Fragmentation and Reassembly . . . . . . . . . . . . . 11
4.2.6. Extension at 6lo Adaptation Layer . . . . . . . . . . 12
5. Internet Connectivity Scenarios and Topologies . . . . . . . . 12
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
7. Security Consideration . . . . . . . . . . . . . . . . . . . . 14
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.1. Normative References . . . . . . . . . . . . . . . . . . . 15
8.2. Informative References . . . . . . . . . . . . . . . . . . 15
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
The idea of using power line for both electricity supply and
communication can be traced back to the beginning of the last
century. With the obvious advantage of existing power grid, PLC is a
good candidate for supporting various service scenarios such as in
houses and offices, in trains and vehicles, in smart grid and
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advanced metering infrastructure (AMI). Such applications cover the
smart meters for electricity, gas and water that share the common
features like fixed position, large quantity, low data rate, and long
life time.
Although PLC technology has an evolution history of several decades,
the adaptation of PLC for IP based constrained networks is not fully
developed. The 6lo related scenarios lie in the low voltage PLC
networks with most applications in the area of Advanced Metering
Infrastructure, Vehicle-to-Grid communications, in-home energy
management and smart street lighting. It is of great importance to
deploy IPv6 for PLC devices for its large address space and quick
addressing. In addition, due to various existing PLC standards, a
comparison among them is needed to facilitate the selection of the
most applicable PLC standard in certain using scenarios.
The following sections provide a brief overview of PLC, then describe
transmission of IPv6 packets over PLC networks. The general approach
is to adapt elements of the 6LoWPAN specifications [RFC4944],
[RFC6282], and [RFC6775] to constrained PLC networks. Similar 6LoPLC
adaptation layer was previously proposed in [draft-popa-6lo-6loplc],
however, with the same purpose, this document provides more updated,
structured and instructive information for the deployment of IPv6
over PLC networks.
2. Requirements Notation and Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
Below are the terms used in this document:
6LoWPAN: IPv6 over Low-Power Wireless Personal Area Network
AMI: Advanced Metering Infrastructure
BBPLC: Broadband Power Line Communication
BR: Border Router
HDPLC: High Definition Power Line Communication
IID: Interface Identifier
LAN: Local Area Network
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LOADng: Lightweight On-demand Ad-hoc Distance-vector Routing Protocol
Next Generation
MSDU: MAC Service Data Unit
MTU: Maximum Transmission Unit
NBPLC: Narrowband Power Line Communication
OFDM: Orthogonal Frequency Division Multiplexing
PLC: Power Line Communication
PSDU: PHY Service Data Unit
RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks
WAN: Wide Area Network
3. Overview of PLC
PLC technology enables convenient two-way communications for home
users and utility companies to monitor and control electric plugged
devices such as electricity meters and street lights. Due to its
large range of communication frequencies, PLC is generally classified
into two categories: Narrowband PLC (NBPLC) for automation of
sensors, and Broadband PLC (BBPLC) for home and industry networking
applications. Various standards have been addressed on the MAC and
PHY layers for this communication technology, e.g. IEEE 1901 and ITU-
T G.hn for BBPLC (1.8-250 MHz), IEEE 1901.2, ITU-T G.9902 (G.hnem),
ITU-T G.9903 (G3-PLC) and ITU-T G.9904 (PRIME) for NBPLC (3-500 kHz)
and the recent proposal for the IEEE 1901.1 standard aiming at the
frequency band of 2-12 MHz.
Narrowband PLC is a very important branch of PLC technology due to
its low frequency band and low power cost. So far the recent PLC
standards, ITU-T G.9903 (G3-PLC) and IEEE 1901.2, are dominating as
two of the most robust schemes available. Different networking
methods exist in different NBPLC standards. The formation of a ITU-T
G.9903 network is based on a MAC Layer routing protocol called LOADng
(Lightweight On-demand Ad-hoc Distance-vector Routing Protocol Next
Generation). Different from ITU-T G.9903, IEEE 1901.2 enables a
variable structure of the MAC layer which can alternatively apply
layer-2 or layer-3 mesh networking. IEEE 1901.2 enables a
coexistence mode with ITU-T G.9903 using layer-2 LOADng protocol, and
on the other hand it allows the adaptation of layer-3 RPL protocol
(IPv6 Routing Protocol for Low-Power and Lossy Networks).
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The IEEE 1901.1 WG is currently working on a new PLC standard, IEEE
1901.1, which focuses on the frequency band of 2-12 MHz [IEEE
1901.1]. This promising medium-frequency PLC standard, known as PLC-
IOT, is suitable for 6lo applications thus mentioned in this
document. Details on this standard is to be determined.
3.1. Protocol Stack
The protocol stack for IPv6 over PLC is illustrated in Figure 1 that
contains the following elements from bottom to top: PLC PHY Layer,
PLC MAC Layer, Adaptation layer for IPv6 over PLC, IPv6 Layer,
TCP/UDP Layer and Application Layer. The PLC MAC/PHY layer
corresponds to a certain PLC standard such as IEEE 1901.2 or ITU-T
G.9903. For the Broadband PLC cases, the adaptation layer for IPv6
over PLC MAY not be used unless in some certain specifications. The
deployment of the 6lo adaptation layer are specified in section 4
according to different standards. Routing protocol like RPL on
Network layer is optional according to the specified PLC standard,
for example IEEE 1901.2 MAY use RPL protocol while ITU-T G.9903 MUST
NOT.
+----------------------------------------+
| Application Layer |
+----------------------------------------+
| TCP/UDP |
+----------------------------------------+
| |
| IPv6 |
| |
|----------------------------------------|
| Adaptation layer for IPv6 over PLC |
+----------------------------------------+
| PLC MAC Layer |
| (IEEE 1901.2 MAC/ITU-T G.9903 MAC) |
+----------------------------------------+
| PLC PHY Layer |
| (IEEE 1901.2 PHY/ITU-T G.9903 PHY) |
+----------------------------------------+
Figure 1: PLC Protocol Stack
3.2. Addressing Modes
Two addressing modes are enabled in PLC including the IEEE 64-bit
extended address and the 16-bit short address which is unique within
the PAN [IEEE 1901.2, ITU-T G.9903]. Physical addressing uses a
globally unique 64-bit address to represent each node on the
powerline. This is useful when initializing a system because the
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nodes do not have unique logical addresses on power up. Logical
addressing uses 16-bit short address to represent each node on the
powerline with a much lower latency and higher throughput. Note that
in ITU-T G.9930, though two addressing modes are enabled, only 16-bit
addressing is supported in mesh routing.
3.3. Maximum Transmission Unit
Maximum Transmission Unit (MTU) of MAC layer is an important
parameter that determines the applicability of fragmentation and
reassembly at the adaptation layer of IPv6 over PLC. IPv6 requires
that every link in the Internet have an MTU of 1280 octets or
greater, thus for a MAC layer with MTU lower than this limit,
fragmentation and reassembly at the adaptation layer are required.
As a wired communication technology, the MTU of PLC MAC layer is
normally higher than wireless technology based on IEEE 802.15.4. The
IEEE 1901.2 MAC layer supports the MTU of 1576 octets (the original
value 1280 byte was updated in 2015 [IEEE 1901.2a]). The MTU for
ITU-T G.9903 is 400 octets, insufficient for supporting complete IPv6
packets. For this concern, fragmentation/reassembly in [RFC 4944]
MUST be enabled for the G.9903-based scenarios (details can be found
in section 4.2.5).
4. Specification of IPv6 over Narrowband PLC
Due to the narrow bandwidth and low data rate in NBPLC, a 6lo
adaptation layer is needed to support the transmission of IPv6
packets. 6LoWPAN standards [RFC 4944], [RFC 6775], and [RFC 6282]
provides useful functionality including link-local IPv6 addresses,
stateless address auto-configuration, neighbor discovery and header
compression. These standards are referred in the specifications of
the 6lo adaptation layer which is illustrated in the following
subsections.
4.1. IEEE 1901.2
4.1.1. Stateless Address Autoconfiguration
An IEEE 1901.2 device performs stateless address autoconfiguration
according to [RFC 4944] so as to obtain an IPv6 Interface Identifier
(IID). In the 16-bit short addressing mode, the 64-bit IID SHALL be
derived by insert 16-bit "FFEE" into a "pseudo 48-bit address" which
is formed by the 16-bit PAN ID, 16-bit zero and the 16-bit short
address as follows:
16_bit_PAN:00FF:FE00:16_bit_short_address
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Considering that this derived IID is not globally unique, the
"Universal/Local" (U/L) bit (7th bit) SHALL be set to zero.
For the EUI-64 addressing mode, as per [RFC 2464], the Interface
Identifier is then formed from by complementing the U/L bit,
generally setting to 1, since an interface's built-in address is
expected to be globally unique.
4.1.2. IPv6 Link Local Address
The IPv6 link-local address [RFC4291] for an IEEE 1901.2 interface is
formed by appending the Interface Identifier, as defined above, to
the prefix FE80::/64 (see Figure 2).
10 bits 54 bits 64 bits
+----------+-----------------------+----------------------------+
|1111111010| (zeros) | Interface Identifier |
+----------+-----------------------+----------------------------+
Figure 2: IPv6 Link Local Address in IEEE 1901.2
4.1.3. Unicast and Multicast Address Mapping
The address resolution procedure for mapping IPv6 unicast addresses
into IEEE 1901.2 link-layer addresses follows the general description
in section 7.2 of [RFC4861], unless otherwise specified.
The Source/Target Link-layer Address option has the following forms
when the link layer is IEEE 1901.2 and the addresses are EUI-64 or
16-bit short addresses, respectively.
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0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length=2 | | Type | Length=1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | 16-bit short Address |
+- IEEE 1901.2 -+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EUI-64 | | Padding |
+- -+ +- -+
| | | (all zeros) |
+- Address -+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- Padding -+
| |
+- (all zeros) -+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Unicast Address Mapping in IEEE 1901.2
Option fields:
Type: 1 for Source Link-layer address and 2 for Target Link-layer
address.
Length: This is the length of this option (including the type and
length fields) in units of 8 octets. The value of this field is 2 if
using EUI-64 addresses, or 1 if using 16-bit short addresses.
IEEE 1901.2 Address: The 64-bit IEEE 1901.2 address, or the 16-bit
short address. This is the address the interface currently responds
to. This address may be different from the built-in address used to
derive the Interface Identifier, because of privacy or security
(e.g., of neighbor discovery) considerations.
Multicast address mapping is not supported in IEEE 1901.2. A link-
local multicast only reaches neighbors within direct physical
connectivity. IEEE 1901.2 excludes the functionality of multicast
either in [RFC 4944] or in coexistence modes with G3-PLC and PRIME.
However, IEEE 1901.2 supports the required MTU by IPv6, eliminating
the need of fragmentation and reassembly at the 6lo adaptation layer,
so the multicast functionality in this case is applicable and is
RECOMMENDED in this document.
4.1.4. Header Compression
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The IEEE 1901.2 PHY layer supports a maximum PSDU (PHY Service Data
Unit) of 512 octets while the allowed PHY payload is smaller and can
change dynamically based on channel conditions. Due to the limited
PHY payload, header compression at 6lo adaptation layer is of great
importance and MUST be applied. The compression of IPv6 datagrams
within IEEE 1901.2 frames refers to [RFC 6282], which updates [RFC
4944]. Header compression as defined in RFC6282 which specifies the
fragmentation methods for IPv6 datagrams on top of IEEE 802.15.4, is
REQUIRED in this document as the basis for IPv6 header compression in
IEEE 1901.2. All headers MUST be compressed according to RFC6282
encoding formats.
4.1.5. Fragmentation and Reassembly
To cope with the mismatch between the size of the PHY frame payload
and the size of the MAC Service Data Unit (MSDU), IEEE 1901.2 MAC
layer provides the functionality of segmentation and reassembly. A
Segment Control Field is defined in the MAC frame header regardless
of whether segmentation is required. This process segments a MAC
layer datagram into multiple fragments and provides a reliable one-
hop transfer of the resulting fragments. However, for the 6lo
adaptation layer, since IEEE 1901.2 naturally supports a MAC payload
of 1280 octets, the minimum MTU of IPv6, there is no need for
fragmentation and reassembly for the IPv6 packet transmission. This
document specifies that, in the IPv6 packet transmission over IEEE
1901.2, fragmentation and reassembly in [RFC 4944] MUST NOT be used.
4.2. ITU-T G.9903
4.2.1. Stateless Address Autoconfiguration
The stateless address auto-configuration in ITU-T G.9903 also refers
to [RFC 4944] with the following selections: The 64-bit interface
identifier shall be derived from a "pseudo 48-bit address" formed
with the PAN identifier and the short address as follows:
0xYYYY:00FF:FE00:XXXX where 0xYYYY is the PAN identifier and XXXX is
the short address. Additional care shall be taken when choosing a
PAN identifier so as not to interfere with I/G and U/L bits of the
interface identifier. If the PAN identifiers are chosen randomly,
then the U/L and I/G bits (7th and 8th bits) shall be set to zero
[ITU-T G.9903].
4.2.2. IPv6 Link Local Address
In ITU-T G.9903, the formation of IPv6 link-local address follows the
same process as IEEE 1901.2 (see section 4.1.2) by appending the
Interface Identifier (IID) to the prefix FE80::/64.
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4.2.3. Unicast and Multicast Address Mapping
The address resolution procedure for mapping IPv6 unicast addresses
into ITU-T G.9903 link-layer addresses follows the general
description in section 7.2 of [RFC4861], unless otherwise specified.
Source/Target link-layer address option field SHOULD contain the EUI-
64 address or the combined address with PAN ID and 16-bit short
address of the source or target device as below. Note that the
format of the Target Link-layer address in ITU-T G.9903 (see Figure
4) is specified according to the Annex E of [ITU-T G.9903].
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length=2 | | Type | Length=1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | PAN ID |
+- ITU-T G.9903 -+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EUI-64 | | 16-bit short Address |
+- -+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address | | (all zeros) |
+- -+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- Padding -+
| |
+- (all zeros) -+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Unicast Address Mapping in ITU-T G.9903
Option fields:
Type: 1 for Source Link-layer address and 2 for Target Link-layer
address.
Length: This is the length of this option (including the type and
length fields) in units of 8 octets. The value of this field is 2 if
using EUI-64 addresses, or 1 if using 16-bit short addresses.
ITU-T G.9903 Address: The 64-bit IEEE 1901.2 address, or the 16-bit
short address. This is the address the interface currently responds
to. This address may be different from the built-in address used to
derive the Interface Identifier, because of privacy or security
(e.g., of neighbor discovery) considerations.
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The address resolution procedure for mapping IPv6 multicast addresses
into ITU-T G.9903 link-layer addresses follows the general
description in [RFC 4944] and MUST only be used in a mesh-enabled
network. An IPv6 packet with a multicast destination address (DST),
consisting of the sixteen octets DST[1] through DST[16], is
transmitted to the following 802.15.4 16-bit multicast address (see
Figure 5):
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1 0 0|DST[15]* | DST[16] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Multicast Address Mapping
Here, DST[15]* refers to the last 5 bits in octet DST[15], that is,
bits 3-7 within DST[15]. The initial 3-bit pattern of "100" follows
the 16-bit address format for multicast addresses (see Section 12 of
[RFC 4944]).
4.2.4. Header Compression
Header compression as defined in [RFC6282], which specifies the
compression format for IPv6 datagrams on top of IEEE 802.15.4, is
REQUIRED in this document as the basis for IPv6 header compression in
ITU-T G.9903. All headers MUST be compressed according to [RFC6282]
encoding formats.
4.2.5. Fragmentation and Reassembly
Similar to IEEE 1901.2, Segment Control Field is also defined in the
ITU-T G.9903 MAC frame header, and the functionality of fragmentation
and reassembly is also enabled at the G.9903 MAC layer. However, the
maximum MAC payload size is fixed to 400 octets at the present ITU-T
G.9903 recommendation, thus to cope with the required MTU of 1280
octets by IPv6, fragmentation and reassembly at 6lo adaptation layer
MUST be provided referring to [RFC 4944].
To avoid the duplicate fragmentation at both 6lo adaptation layer and
ITU-T G.9903 MAC layer, an optional way is to limit the MAC payload
size so that the MSDU can fit the PHY payload without MAC layer
fragmentation. However, the number of data bytes of the PHY payload
can change dynamically based on channel conditions (see section 9.3
in [ITU-T G.9903]), so the best solution is incrementing the allowed
MAC payload size above 1280 octets so as to avoid the use of
fragmentation and reassembly at 6lo adaptation layer.
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4.2.6. Extension at 6lo Adaptation Layer
Apart from the 6Lo headers specified in [RFC 4944], an additional
command frame header is defined for the mesh routing procedure which
appears in the following order: Mesh addressing header, Broadcast
header, Fragmentation header, Command frame header [ITU-T G.9903].
Figure 6 shows an example of the command frame: The ESC header type
(01000000b) indicates an additional dispatch byte follows (see [RFC
4944] and [RFC 6282]). Then this 1-octet dispatch field is used as
the Command frame header and filled with the Command ID. This header
shall be in the last position if more than one header is present in
the frame. The Command ID can be classified into 4 types:
- LOADng message (0x01)
- LoWPAN bootstrapping protocol message (0x02)
- Reserved by ITU-T (0x03-0x0F)
- CMSR protocol messages (0X10-0X1F)
0 1 2
Bits 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+---------------+---------------+-----------------
|ESC header type| |
| | Command ID | Command Payload
| 01 000000b | |
+---------------+---------------+-----------------
Figure 6: Command Frame Header Format of ITU-T G.9903
For the Mesh addressing type and header, it is worthy to note that
the value of the HopsLeft field SHALL not exceed adpMaxHops. When
the originator and final destination devices are neighbors (i.e., the
next hop address equals the final destination address and the next
hop address is present in the originator's neighbor table), the mesh
header shall be omitted in the frame.
5. Internet Connectivity Scenarios and Topologies
The network model can be simplified to two kinds of network devices:
Border Router (BR) and Node. BR is the coordinator of the PLC subnet
and can be seen as a master node while Nodes are typically PLC meters
and sensors. The IPv6 over PLC networks SHOULD be built as tree,
mesh or star according to the specified using scenarios. Every
network requires at least one BR to communicate with each nodes.
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One common topology in the current PLC scenarios is star. In this
case, the communication at the link layer only takes place between a
node and a BR. The BR collects data (e.g. smart meter reading) from
different nodes, and then concentrates and uploads the data through
Ethernet or LPWAN (see Figure 7). The collected data is transmitted
by the smart meters through PLC, aggregated by a concentrator, sent
to the utility and then to a Meter Data Management System for data
storage, analysis and billing.
Node Node
\ / +---------
\ / /
\ / +
\ / |
Node ------ BR =========== | Internet
/ \ |
/ \ +
/ \ \
/ \ +---------
Node Node
<---------------------->
PLC subnet
Figure 7: PLC Star Network connected to the Internet
Tree topology is used when the distance between a node A and BR is
beyond the PLC allowed limit while there is another node B in between
able to communicate with both sides. Node B in this case acts both
as a 6lo Node and a Proxy Coordinator (PCO). For this scenario, the
link layer communications take place between node A and node B, and
between node B and BR. An example of PLC tree network is depicted in
Figure 8. This topology can be applied in the smart street lighting,
where the lights adjust the brightness to reduce energy consumption
while sensors are deployed on the street lights to give information
such as wind speed, temperature, humidity. Data transmission
distance in the street lighting scenario is normally above several
kilometers thus the PLC tree network is required. A more
sophisticated AMI network may also be constructed into the tree
topology which as depicted in [RFC 8036].
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Node
\ +---------
Node \ /
\ \ +
\ \ |
Node --- Node ----- BR ========== | Internet
/ / |
/ / +
Node --- Node / \
/ +---------
Node --- Node
<------------------------->
PLC subnet
Figure 8: PLC Tree Network connected to the Internet
Mesh networking in PLC is still under development but of great
potential applications. By connecting all nodes with their neighbors
in communication range (see Figure 9), mesh topology dramatically
enhances the communication efficiency and thus expands the size of a
PLC network. A simple use case is the smart home scenario where the
ON/OFF state of air conditioning is controlled by the state of home
lights (ON/OFF) and doors (OPEN/CLOSE).
Node ----- Node
/ \ / \ +---------
/ \ / \ /
/ \ / \ +
/ \ / \ |
Node --- Node ---- Node ----- BR =========== | Internet
\ / \ / |
\ / \ / +
\ / \ / \
\ / \ / +---------
Node ----- Node
<--------------------------------->
PLC subnet
Figure 9: PLC Mesh Network connected to the Internet
6. IANA Considerations
There are no IANA considerations related to this document.
7. Security Consideration
Hou, et al [Page 14]
INTERNET DRAFT IPv6 over PLC March 10, 2017
This document has no security consideration beyond those in [RFC
4944] and [RFC 6282].
8. References
8.1. Normative References
[IEEE 1901.2] IEEE-SA Standards Board, "IEEE Standard for Low-
Frequency (less than 500 kHz) Narrowband Power Line
Communications for Smart Grid Applications", IEEE 1901.2,
October 2013,
<https://standards.ieee.org/findstds/standard/1901.2-
2013.html>.
[ITU-T G.9903] International Telecommunication Union, "Narrowband
orthogonal frequency division multiplexing power line
communication transceivers for G3-PLC networks", ITU-T
G.9903, February 2014, <https://www.itu.int/rec/T-REC-
G.9903>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI
10.17487/RFC2119, March 1997, <http://www.rfc-
editor.org/info/rfc2119>.
[RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet
Networks", RFC 2464, December 1998, <http://www.rfc-
editor.org/info/rfc2464>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, DOI
10.17487/RFC4861, September 2007, <http://www.rfc-
editor.org/info/rfc4861>.
[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4 Networks",
RFC 4944, September 2007, <http://www.rfc-
editor.org/info/rfc4944>.
[RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
September 2011, <http://www.rfc-editor.org/info/rfc6282>.
8.2. Informative References
[draft-popa-6lo-6loplc] Popa, D. and J.H. Hui, "6LoPLC: Transmission
of IPv6 Packets over IEEE 1901.2 Narrowband Powerline
Communication Networks", draft-popa-6lo-6loplc-ipv6-over-
Hou, et al [Page 15]
INTERNET DRAFT IPv6 over PLC March 10, 2017
ieee19012-networks-00, March 2014,
<https://tools.ietf.org/html/draft-popa-6lo-6loplc-ipv6-
over-ieee19012-networks-00>.
[IEEE 1901.1] IEEE-SA Standards Board, "Standard for Medium Frequency
(less than 15 MHz) Power Line Communications for Smart Grid
Applications", IEEE 1901.1, work in progress,
<http://sites.ieee.org/sagroups-1901-1>.
[IEEE 1901.2a] IEEE-SA Standards Board, "IEEE Standard for Low-
Frequency (less than 500 kHz) Narrowband Power Line
Communications for Smart Grid Applications - Amendment 1",
IEEE 1901.2a, September 2015,
<https://standards.ieee.org/findstds/standard/1901.2a-
2015.html>.
[ITU-T G.9960] International Telecommunication Union, "Unified high-
speed wireline-based home networking transceivers - System
architecture and physical layer specification", ITU-T
G.9960, December 2011, <https://www.itu.int/rec/T-REC-
G.9960>.
[ITU-T G.9961] International Telecommunication Union, "Unified high-
speed wireline-based home networking transceivers - Data
link layer specification", ITU-T G.9961, June 2010,
<https://www.itu.int/rec/T-REC-G.9961>.
[RFC 8036] Cam-Winget, N., Hui, J. and D. Popa, "Applicability
Statement for the Routing Protocol for Low-Power and Lossy
Networks (RPL) in Advanced Metering Infrastructure (AMI)
Networks", RFC 8036, January 2017, <http://www.rfc-
editor.org/info/rfc8036>.
9. Acknowledgments
Authors wish to thank Yizhou Li and Yuefeng Wu for their valuable
comments and contributions.
Authors' Addresses
Jianqiang Hou
Huawei Technologies
101 Software Avenue,
Nanjing 210012
China
Phone: +86 15852944235
Email: houjianqiang@huawei.com
Hou, et al [Page 16]
INTERNET DRAFT IPv6 over PLC March 10, 2017
Yong-Geun Hong
Electronics and Telecommunications Research Institute
161 Gajeong-Dong Yuseung-Gu
Daejeon 305-700
Korea
Phone: +82 42 860 6557
Email: yghong@etri.re.kr
Xiaojun Tang
State Grid Electric Power Research Institute
19 Chengxin Avenue
Nanjing 211106
China
Phone: +86-25-81098508
Email: itc@sgepri.sgcc.com.cn
Hou, et al [Page 17]