CN111181823B

CN111181823B - Network transmission system based on CAN bus and robot system

Info

Publication number: CN111181823B
Application number: CN201911415815.5A
Authority: CN
Inventors: 李晖; 黄晓庆
Original assignee: Cloudminds Robotics Co Ltd
Current assignee: Cloudminds Shanghai Robotics Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-11-05
Anticipated expiration: 2039-12-31
Also published as: CN111181823A

Abstract

The present disclosure relates to a CAN bus-based network transmission system and a robot system, the CAN bus-based network transmission system including a CAN bus and node devices connected to the CAN bus, the node devices connected to the CAN bus including a master node and a slave node, each of the master nodes being configured as a border router defined in the 6LoWPAN standard; each of the slave nodes is configured as a node defined in the 6LoWPAN standard. The technical problem that great difficulty exists in expanding equipment application to native CAN for equipment needing CAN and IPv6 in the related technology is solved. By popularizing the method defined in the 6LoWPAN standard to the CAN, a foundation is provided for expanding more applications to the native CAN, and the difficulty of moving the applications to the native CAN is reduced.

Description

Network transmission system based on CAN bus and robot system

Technical Field

The present disclosure relates to the field of communications, and in particular, to a network transmission system and a robot system based on a CAN bus.

Background

CAN is an abbreviation of Controller Area Network, is one of the most widely used protocols for data transmission internationally, and is widely used in the fields of vehicles, industrial automation and the like due to its advantages of high reliability, real-time performance and the like.

IPv6 is an abbreviation of Internet Protocol Version 6 (Internet Protocol Version 6), which solves the problem of limited amount of network address resources of IPv4(Internet Protocol Version 4) and is thus being used to gradually replace IPv 4.

There is not much information about introducing the IPv6 network transmission system based on CAN in the related art, and there is a certain technical difficulty in using the two protocols in some technical fields that need to use the two protocols in combination, for example, there is a great difficulty in expanding the application to native CAN for some devices that need to use CAN and IPv 6.

Disclosure of Invention

The main purpose of the present disclosure is to provide a network transmission system and a robot system based on a CAN bus, which are used to solve the technical problem of great difficulty in expanding IPv6 application to a native CAN in the related art.

In order to achieve the above object, a first aspect of the embodiments of the present disclosure provides a network transmission system based on a CAN bus, including a CAN bus and node devices connected to the CAN bus, where the node devices connected to the CAN bus include a master node and a slave node;

wherein each of the master nodes is configured as a border router 6LBR defined in the 6LoWPAN standard;

each said slave node is configured as a node 6LN defined in the 6LoWPAN standard;

and the node devices transmit data in a single-hop mode.

Optionally, the CAN bus-based network transmission system is configured to compress the 6LoWPAN packet header using a 6LoWPAN Context Option defined in 6LoWPAN Neighbor Discovery Optimization for6LoWPAN networks, compress and decompress the IPv6 packet header according to a LoWPAN _ IPHC encoding format, and compress and decompress the next IPv6 packet header and other layer packet headers according to a LoWPAN _ NHC encoding format.

Optionally, the network transmission system based on the CAN bus supports extension of multiple logical links on the basis of ISO-TP at a data link layer, and a maximum transmission unit for transmitting data with a size of 1280 bytes is implemented between node devices of the network transmission system based on the CAN bus in a manner of segmented transmission based on the multiple logical links at the data link layer.

Optionally, the node devices of the network transmission system based on the CAN bus transmit the data maximum transmission unit with the size of 1280 bytes on a data Link layer through a segmented transmission mode according to 6LoWPAN, wherein the data Link layer does not support an ISO-TP/Multi-Logical-Link ISO-TP segmented network protocol stack.

Optionally, the Interface ID of the 64-bit network Interface identifier of the node device connected to the CAN bus is generated according to at least one of the MAC address of the node device, a randomly generated 64-bit numerical value, and a node address of the node device on the CAN bus.

Optionally, the Interface ID of the 64-bit network Interface identifier of the node device connected to the CAN bus is obtained as follows:

taking the node address on the CAN bus as the address of the node equipment in a data link layer;

generating a 16-bit 6LoWPAN short address from the 8-bit node address according to a preset rule;

and mapping the 16-bit 6LoWPAN short address to an IEEE EUI-64 address restriction space, and generating a 64-bit network Interface mark Interface ID of the node equipment.

Optionally, the IPv6 unicast addresses of the node devices connected on the CAN bus are generated based on the 64-bit network Interface label Interface ID, so that the Interface label parts of the IPv6 unicast addresses of the source node and the destination node do not need to be transmitted on the CAN bus, but are derived from the node addresses of the source node and the destination node on the CAN bus;

the IPv6 unicast address includes: a local link address, a globally unique address, a locally unique address.

Optionally, the IPv6 multicast address of each node device connected to the CAN bus is mapped to the same one reserved address on the CAN data link layer, and the IPv6 multicast address includes a known multicast address, an address of a requesting node, and a transient address of a node.

Optionally, each of the primary nodes as the border router 6LBR needs to comply with Neighbor Discovery for IPv6 (Neighbor Discovery for IPv6) and its related specification definition; and the number of the first and second electrodes,

a 6LoWPAN Context Option (6LoWPAN Context Option) defined in Neighbor Discovery Optimization for6LoWPAN related specifications supporting 6 LoWPAN; and the number of the first and second electrodes,

following the compression format related specification of IPv6 datagram on IEEE 802.15.4 based network to compress and decompress IPv6 packet header according to LOWPAN _ IPHC encoding format, and compress and decompress the next IPv6 packet header and other layer packet header according to LOWPAN _ NHC encoding format; and the number of the first and second electrodes,

the following functions and processing flows defined in Neighbor Discovery Optimization for6 lowwans related specification without supporting 6LoWPAN are required:

supporting host-initiated interactions of a sleeping host;

canceling host resolution of the multicast-based address;

using a host address registration function of the new option in the unicast neighbor solicitation and neighbor broadcast message;

multi-hop release of prefix and 6LoWPAN packet header compression context information;

multi-hop duplicate address detection using two new ICMPv6 message types.

Optionally, each slave node as the node 6LN needs to follow Neighbor Discovery of IPv6 (Neighbor Discovery for IPv6) and its related specification definition; and the number of the first and second electrodes,

supporting host-initiated interactions of a sleeping host;

canceling host resolution of the multicast-based address;

the host address registration function using the new option in unicast neighbor solicitation and neighbor broadcast messages. The embodiment of the disclosure also provides a robot system, and the network transmission system based on the CAN bus is formed among all nodes of the robot system.

By adopting the technical scheme, the following technical effects can be at least achieved:

in the technical scheme provided by the embodiment of the disclosure, the network transmission system based on the CAN bus comprises the CAN bus and node equipment connected on the CAN bus, wherein the node equipment connected with the CAN bus comprises a main node and a slave node; wherein each of the master nodes is configured as a border router 6LBR defined in the 6LoWPAN standard; each slave node is configured to be a node 6LN defined in the 6LoWPAN standard, and by popularizing the method defined in the 6LoWPAN standard to the CAN, a foundation is provided for expanding more IPv6 applications to the native CAN, and the difficulty in moving IPv6 applications to the native CAN is reduced.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

fig. 1 is a block diagram illustrating a CAN bus based network transmission system according to an exemplary embodiment.

Fig. 2 is a flowchart illustrating a manner of generating a network interface flag of a node device in a CAN bus based network transmission system according to an exemplary embodiment.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

The disclosed embodiment provides a network transmission system based on CAN bus, which may be referred to as a 6-CAN system for short, fig. 1 is a block diagram of an IPv6 network transmission system 10 based on CAN according to an exemplary embodiment, as shown in fig. 1, the network transmission system 10 based on CAN bus includes a CAN bus 101, and node devices connected to the CAN bus 101, where the node devices connected to the CAN bus 101 include a master node 102 and a slave node 103;

wherein each of the master nodes 102 is configured as a border router 6LBR defined in the 6LoWPAN standard;

each of said slave nodes 103 is configured as a node 6LN defined in the 6LoWPAN standard;

and the node devices transmit data in a single-hop mode.

In the embodiment of the present disclosure, a 6LoWPAN (IPv6 over Low power Wireless Personal Area Network) is a Network layer adaptation layer for supporting transmission of IPv6 on a Low power consumption Wireless Personal Area Network, and is between a data link layer and a Network layer.

Specifically, the master node 102 in the CAN bus-based network transmission system 10 is configured as a Border Router (Border Router) defined in the 6LoWPAN standard, the slave node 103 is configured as a node defined in the 6LoWPAN standard, and after externally transmitted data enters the CAN bus-based network transmission system 10 through the master node 102, information CAN be transmitted to the corresponding slave node according to the network interface flag of the slave node 103 to complete transmission of the information, so that the IPv6 application on the slave node 103 CAN implement corresponding functions according to the transmitted information. For the external terminal, specific hardware difference and communication details are not considered, and only the message transmission is carried out aiming at the corresponding network interface mark, so that specific protocol conversion details can be omitted, and the design and implementation overhead of the upper-layer application is simplified.

Specifically, there are typically at most 2 master nodes 102 on a CAN bus 101, such as only active master nodes, or both active and standby master nodes, where a standby master node is a standby node for an active master node. Also, the number of slave nodes 103 on one CAN bus 101, limited by the addressing capability of the CAN bus, is at most 254 nodes (addresses 0 and 255 reserved for the system).

When the master node 102 is configured, for part of functions and processing flows defined in Neighbor Discovery Optimization for6 lowwans (Neighbor Discovery Optimization for6 lowwans), support is not needed, and the functions and processing flows that do not need support specifically include:

host-initiated interactions to allow for sleeping hosts (Host-initiated hosts);

canceling host resolution of multicast-based addresses (latency of multicast-based addresses for hosts);

using the host address registration work of the new option in the unicast neighbor solicitation and neighbor broadcast message;

multi-hop duplicate address detection using two new ICMPv6 message types.

When the slave node 103 is configured, for part of functions and processing flows defined in Neighbor Discovery Optimization for6 lowwans, support is not required, and the functions and processing flows which are not required to be supported specifically include:

supporting host-initiated interactions of a sleeping host;

canceling host resolution of the multicast-based address;

the host address registration function using the new option in unicast neighbor solicitation and neighbor broadcast messages.

The structure of a Protocol stack used by the system 10 is similar to an IPv6 Protocol stack based on a 6LoWPAN, and the Protocol stack of the system 10 includes an application layer, a transport layer, a network layer, a data Link layer and a physical layer, where the transport layer may use UDP (User data Protocol) and TCP (Transmission Control Protocol), the network layer may use IPv6, and the data Link layer supports an extension of a Multi-Logical Link (Multi-Logical-Link) on the basis of ISO-TP (International Organization for Standardization-transport Protocol), that is, the ISO-TP/Multi-Logical-Link ISO-is ISO 15765-2 in the ISO standard: 2016(E), in practical applications, implementation of each slave node 103 may be determined according to the processing capability and specific application condition of the CAN node, and a Maximum Transmission Unit (MTU) of data with a size of 1280 bytes is transmitted between node devices of the system 10 in a data link layer based on a multi-logical link in a segmented Transmission manner.

Regarding the way of segmented transmission, specifically, for the system 10 supporting the expansion of multiple Logical links, the segmented transmission way provided by the above ISO-TP/Multi-Logical-Link ISO-TP is utilized to implement, so that the maximum transmission unit for transmitting data with a size of 1280 bytes can be implemented between node devices of the system 10 in the data Link layer by the segmented transmission way according to the ISO-TP/Multi-Logical-Link ISO-TP; for the system 10 that does not support the expansion of multiple logical links, the method may be implemented by using a segmented transmission method provided by the 6LoWPAN, so that the maximum transmission unit of data with a size of 1280 bytes may be transmitted between node devices of the system 10 according to the segmented transmission method of the 6 LoWPAN. In addition, for the system 10 supporting the expansion of the multi-logical link, the Data link layer and the transport layer also support CAN 2.0A, CAN 2.0B, and CAN FD (CAN with Flexible Data-Rate) protocols, whereas for the system 10 not supporting the expansion of the multi-logical link, the Data link layer and the transport layer may only provide support for the CAN FD protocols.

In addition, for the purpose of CAN compatibility, a single-hop network is formed between each of the nodes 6LN in the system 10, and between the Node 6LN and the border router 6LBR, that is, between all the master nodes 102 and the slave nodes 103, and between all the slave nodes 103, data is transmitted in a single-hop (single hop) manner, and the slave nodes 103 are configured to implement the function of the 6LoWPAN Node (6LN), which may specifically refer to the description of the 6LoWPAN Node in the prior art, and this disclosure is not specifically set forth.

Through the technical scheme, the network transmission system 10 based on the CAN bus comprises the CAN bus 101 and node devices connected to the CAN bus 101, the node devices connected to the CAN bus 101 comprise the master nodes 102 and the slave nodes 103, wherein each master node 102 is configured as a boundary router defined in the 6LoWPAN standard, and each slave node 103 is configured as a node defined in the 6LoWPAN standard, so that the method defined in the 6LoWPAN standard is popularized to the CAN, a foundation is provided for expanding more applications to the native CAN, and the difficulty of moving the applications to the native CAN is reduced.

Optionally, in the system 10, the 64-bit network Interface identifier (Interface ID) of the node device connected to the CAN bus is generated according to at least one of a Media Access Control (MAC) address of the node device, a randomly generated 64-bit numerical value, and a node address of the node device on the CAN bus 101.

Specifically, taking the node address of the node device on the CAN bus 101 as an example, as shown in fig. 2, the 64-bit network interface flag of the node device connected to the CAN bus is obtained as follows:

and S11, taking the node address on the CAN bus as the address of the node device at the data link layer.

Referring to the definition of the address information parameter N _ AI in ISO-TP, the node address on the CAN bus 101 is defined to be 8 bits, assuming a valid range of 0-255, where address 0 is reserved by the system 10 for mapping the IPv6 multicast address of the node device and is used only as a destination address, and address 255 may also be reserved for mapping the IPv6 unspecified (unspecified) address of the node device and is used only as a source address. The addresses 1-254 are used for allocating node devices as node addresses, which can be used as source addresses or destination addresses, and the specific allocation can be controlled by the master node 102. The number of bytes required for transmitting the network interface flag CAN be saved by using the node address on the CAN bus 101 as the address of the node device at the data link layer.

And S12, generating a 16-bit 6LoWPAN short address by using the 8-bit node address according to a preset rule.

For example, if the node address is xx (1 x represents 4 bits), a Transmission of IPv6 Packets over a range of 16-bit short addresses (RFC 4944) reserved by IEEE 802.15.4Networks (RFC 4944) may be transmitted according to IPv6 data Packets, and a 16-bit 6LoWPAN short address a0xx may be generated according to the node address.

S13, mapping the 16-bit 6LoWPAN short address to an IEEE EUI-64 address restriction space, and generating a 64-bit network interface mark of the node device.

Wherein, the 16-bit address in the middle of the network interface mark is ff: fe, the 16-bit address in the back is a 16-bit short address, and the rest addresses are 0.

Following the above example, the 6LoWPAN short address a0xx is mapped into an IEEE EUI-64 address constraint space, and the generated network Interface flag of the node device is 0000:00ff: fe00: a0xx, and optionally, the value of the 1 st bit address in the 7 th byte of the network Interface flag is used to determine whether the network Interface flag is a globally unique IPv6 Interface ID or a local IPv6 Interface ID, for example, in a possible implementation, when the 1 st bit address of the 7 th byte is 0, it indicates that the network Interface flag is not 1 globally unique IPv6 Interface ID (globally unique IPv6 Interface Identifier). Table 1 below is an illustration of the use of a 16-bit (64-bit) network interface flag generated with the node address (N _ AI) on the CAN bus:

00000000

11111111

11111110

00000000

10100000

N_AI

TABLE 1

For the MAC address or the randomly generated 64-bit value, the MAC address or the randomly generated 64-bit value may be mapped to a preset network interface flag, or the MAC address or the randomly generated 64-bit value may be transformed by using a preset algorithm to obtain the network interface flag.

Further, with the above system 10, the IPv6 unicast address of the node device connected on the CAN bus is generated based on the network interface flag, and the IPv6 unicast address includes: a local link address (link-local address), a global unique address (global unique address), and a local unique address (unique local address);

when data are transmitted in a unicast mode, the lowest 8 bits of the IPv6 unicast address are obtained by mapping the node address of a source node and the node address of a destination node of a CAN data link layer.

Specifically, the lowest 8 bits of the IPv6 unicast address CAN be directly assigned by the node address of the source node and the node address of the destination node of the CAN data link layer for the system 10 to perform information transmission in a unicast manner. It should be noted that any node device in the system 10 may be used as a source node or a destination node.

Optionally, the IPv6 multicast address of each node device connected to the CAN bus, including a well-known multicast address (i.e. for only special group members, the address is reserved regardless of whether there is any member, and this part of the address is called the well-known multicast address), the address of the requesting node (solicited-node), and the transient address of the node, may be mapped to the same reserved address on the CAN data link layer, and the reserved address may be, for example, N _ AI (0), i.e. address 0.

By adopting the network Interface mark (Interface ID) generation scheme and the mapping scheme of the IPv6 address and the node address (N _ AI) on the CAN bus, the network Interface mark parts of the IPv6 unicast addresses of the source node and the destination node CAN be directly derived from the node address (N _ AI) on the CAN bus without being transmitted on the CAN bus, and the address information transmission is greatly reduced.

Optionally, the CAN bus based network transmission system may be configured to compress the 6LoWPAN header using a 6LoWPAN Context Option defined in Neighbor Discovery Optimization for6LoWPAN options of 6 LoWPAN.

Specifically, the nodes on the CAN bus may use the 6LoWPAN Context Option (6CO) in Neighbor Discovery optimization for6LoWPAN relevant specifications (RFC 6775, RFC 4944, RFC 8505) to compress the packet header with respect to the definition of the prefix address, which may be local or remote.

Table 2 below is an illustration of the 6LoWPAN Context Option format:

TABLE 2

Where Res is a reserved field and C is a prefix address compression identifier.

In addition, the IPv6 packet Header may be compressed and decompressed according to a LOWPAN _ IPHC encoding format (Low-Power Wireless Personal Area Networks-IPv 6 Header Compression, Low-Power Wireless Personal Area Networks-Pv 6 packet Header Compression), and the Next IPv6 packet Header and other layer packet headers may be compressed and decompressed according to a LOWPAN _ NHC encoding format. Wherein the LOWPAN _ IPHC encoding format also indicates whether the next IPv6 packet header uses LOWPAN _ NHC encoding, and if so, the compressed IPv6 packet header is followed by LOWPAN _ NHC encoding.

Table 3 below is an illustration of LOWPAN _ IPHC compressed IPv 6:

TABLE 3

Table 4 below is an illustration of the LOWPAN _ IPHC encoding format:

TABLE 4

Wherein, tf (traffic flow) is a traffic grade, a traffic label; nh (next header) indicates a next header; hlim (hop limit) is the hop limit; CID (context identifier) is a context identifier extension; SAC (Source Address compression) as source Address compression; SAM (Source Address mode) is a source Address mode; m (multicast compression) is multicast compression; DAC (destination Address compression) is used for target Address compression; DAM (destination Address mode) is a target Address mode.

As to the specific manner of compression and decompression, reference may be made to the description of the LOWPAN _ IPHC encoding format and the LOWPAN _ NHC encoding format in the prior art, which is not specifically set forth by the present disclosure.

For the IPv6 unicast address, if the above-described method of generating the network Interface flag (Interface ID) of the node device by using the node address of the node device on the CAN bus 101 is used, the compression efficiency of the address is different depending on whether the method of generating the address is stateless or stateful based on 6CO (stateful). In the case where the stateless link-local address is a source address and/or a destination address, the source address and/or the destination address where the entire link-local address is located CAN be derived from the source address and/or the destination address on CAN bus 101, and therefore CAN be omitted from the IPv6 header. Accordingly, in the aforementioned LOWPAN _ IPHC basic encoding format, the data bit corresponding to the SAM is assigned to 3 (i.e., SAM — 3); and/or; m assigns a data bit of 0 (i.e., M ═ 0), and DAM assigns a data bit of 3 (i.e., DAM ═ 3).

For the IPv6 multicast address, with reference to the above description, the compression efficiency of the address is different based on 6CO (status-based) according to whether the method of address generation is stateless or stateful. In the case of a stateless link-local range, for a well-known multicast address of 1-255 (ff02::1-ff02:: ff), only the lowest 1 byte Group ID (1-255) may be transferred. Accordingly, in the above-mentioned LOWPAN _ IPHC basic encoding format, the data bit corresponding to M is assigned to 1 (i.e., M is 1); and/or; the data bit corresponding to DAC is reset to 0 (i.e., DAC equals 0) and the data bit corresponding to DAM is assigned 3 (i.e., DAM equals 3).

The embodiment of the disclosure also provides a robot system, and the network transmission system based on the CAN bus is formed among all nodes of the robot system. Therefore, the robot based on the IPv6 application is required to be used, and the IPv6 application CAN be directly expanded to a native CAN bus.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A network transmission system based on a CAN bus is characterized by comprising the CAN bus and node equipment connected to the CAN bus, wherein the node equipment connected to the CAN bus comprises a master node and a slave node;

and the node devices transmit data in a single-hop mode.

2. The CAN bus based network transmission system as claimed in claim 1, wherein the CAN bus based network transmission system is configured to compress 6LoWPAN packet headers using 6LoWPAN Context Option defined in Neighbor Discovery Optimization for6LoWPAN networks of 6LoWPAN, compress and decompress IPv6 packet headers according to LoWPAN _ IPHC encoding format, and compress and decompress next IPv6 packet headers and other layer packet headers according to LoWPAN _ NHC encoding format.

3. The CAN-bus-based network transmission system according to claim 1, wherein the CAN-bus-based network transmission system supports extension of multiple logical links on an ISO-TP basis at a data link layer, and a maximum transmission unit for transmitting data of 1280 bytes in size is implemented between node devices of the CAN-bus-based network transmission system by means of segmented transmission at the data link layer based on the multiple logical links.

4. The CAN-bus based network transmission system according to claim 1, wherein a maximum transmission unit of data with a size of 1280 bytes is transmitted between node devices of the CAN-bus based network transmission system through a segmented transmission scheme according to 6LoWPAN on a data Link layer, wherein the data Link layer does not support an ISO-TP/Multi-Logical-Link ISO-TP segmented network protocol stack.

5. The CAN-bus based network transmission system according to any of claims 1-4, wherein the 64-bit network Interface identifier Interface ID of the node device connected to the CAN-bus is generated according to at least one of the MAC address of the node device, a randomly generated 64-bit value, and a node address of the node device on the CAN-bus.

6. The CAN-bus based network transmission system according to any of claims 1-4, wherein the 64-bit network Interface identifier Interface ID of the node device connected to the CAN-bus is obtained by:

7. The CAN-bus based network transmission system according to claim 6, wherein the IPv6 unicast addresses of the node devices connected on the CAN-bus are generated based on the 64-bit network Interface label Interface ID, so that the network Interface label portions of the IPv6 unicast addresses of the source node and the destination node do not need to be transmitted on the CAN-bus but are derived from the node addresses of the source node and the destination node on the CAN-bus;

8. The CAN-bus based network transmission system of claim 6, wherein the IPv6 multicast address of each node device connected on the CAN-bus is mapped to the same one of the reserved addresses on the CAN data link layer, and the IPv6 multicast address comprises a known multicast address, an address of a requesting node, and a transient address of a node.

9. The CAN-bus based network transmission system of claim 1, wherein each of said master nodes as said border router 6LBR needs to comply with Neighbor Discovery for IPv6 (Neighbor Discovery for IPv6) and its related specification definition; and the number of the first and second electrodes,

supporting host-initiated interactions of a sleeping host;

canceling host resolution of the multicast-based address;

multi-hop duplicate address detection using two new ICMPv6 message types.

10. The CAN-bus based network transmission system of claim 1, wherein each said slave node as said node 6LN needs to comply with IPv6 Neighbor Discovery (Neighbor Discovery for IPv6) and its related specification definition; and the number of the first and second electrodes,

supporting host-initiated interactions of a sleeping host;

canceling host resolution of the multicast-based address;

11. A robot system characterized in that the nodes of the robot system form a CAN bus based network transmission system according to any of claims 1-10.