GB/T 30269.303-2018Information technology—Sensor networks—Part 303: Communication and information exchange: Network layer specification for wireless sensor networks based on IP protocol (English PDF)

3.1 Security level

An indication of the protection application is provided in the information transmission.

3.2 Packet

A set of bits that are sent in a format through physical media at the same time.

3.3 Disconnect

A service used to cancel a connection.

3.4 Degree

The number of neighbor nodes in the range of one hop around the node.

3.5 Service data unit

A unit of information transmitted through a service access point.

3.6 Personal network coordinator

A coordinator that serves as the primary control in the personal area network.

Note: In a short-range wireless network, there should generally be one domain network coordinator.

3.7 Encryption

Convert information into another form of expression and require privileged information to restore the original expression.

3.8 Confidentiality

Guarantee information is only disclosed to target customers.

3.9 Connection

A service used to create member affiliations in a wireless personal area network.

3.10 Key

Privilege information used to restrict unauthorized users from accessing information content.

Note: Keys are generally used to protect information from exposure and/or tampering.

3.11 Full-featured device

A device that can be used as a central coordinator.

3.12 Device

An entity that can perform short-range wireless network access control and as a physical layer wireless interface.

Note: The device can be a simplified function device (RFD) or a full-featured device (FFD).

3.13 Protocol data unit

A unit of data exchanged between two layers of entities.

3.14 Neighbor discovery

Nodes used on the same link discover each other's existence, determine each other's MAC layer address, discover routers, and maintain access to The reachability information of the path of the live neighbor.

3.15 Mesh network

A network topology in which any device node can act as both an AP and a router, and each node in the network can send and Receiving signals, each node can communicate directly with one or more peer nodes.

5.1 Overview

5.1 specifies the support provided by the wireless sensor network to form the network topology, and describes the mesh network and the tree network group in detail. a hybrid network in which wireless sensor networks are divided into two peer subnets according to different support protocols. IPv4/IPv6 wireless sensors The internet. Each subnet can be a distributed hybrid network structure. In the network operation, each routing node has a message packet forwarding function. can. After the node completes the information collection, it forwards the gateway through the router and accesses the IPv4/IPv6 backbone network through the gateway. Wireless based on IP protocol The network topology of the sensor network is shown in Figure 1.

Figure 1 defines the following four types of logical function devices.

a) Gateway. responsible for protocol conversion and data mapping between the wireless sensor network and the IPv4/IPv6 backbone network;

b) Coordinator. The manager of the network organization, a network has only one coordinator, responsible for managing other nodes in its network (routing) And child nodes);

c) routing node. implement data transfer;

d) End node. A terminal node is a device that connects a sensor or actuator to a wireless sensor network.

Note: A node refers to a routing node and a terminal node. The client, the client, refers to a program that corresponds to the server and provides local services to the client.

The IPv4/IPv6 backbone network can be Ethernet, a network defined by GB 15629.11-2003, or a network defined by other standards.

The IPv4/IPv6 backbone network and clients are outside the scope of this standard.

The protocol stack structure of the wireless sensor network is based on the OSI model. Each layer provides a series of specifics for the adjacent upper layer Services (such as. the physical layer provides services for the media access control layer), mainly including data entities providing data transmission services and management entities to provide Various services other than data transmission. Each service entity provides an interface to the upper layer of its neighbor through SAP, each SAP supports different service primitives to achieve different functional requirements.

The adaptation layer defines functions such as stateless address autoconfiguration, fragment reassembly, header compression, and deterministic support. Network layer defines routing Mechanisms and algorithms, neighbor discovery services and network and device maintenance.

5.2 Protocol stack structure

The wireless sensor network protocol stack consists of layers and their modules, as shown in Figure 2.

The physical layer and MAC layer of the wireless sensor network shall comply with the requirements of GB/T 15629.15-2010.

The adaptation layer of the wireless sensor network is an intermediate layer defined in the network layer, and provides the MAC layer access to the IP protocol upward.

It is mainly responsible for stateless address autoconfiguration, fragment reassembly, and network layer header compression and deterministic support.

The network layer of the wireless sensor network supports route discovery and maintenance at the network layer between nodes, neighbor discovery and related neighbor information. Save, inter-node data transfer mechanism, and network management and device maintenance.

6.1 Overview

The adaptation layer provides services for the MAC layer of the wireless sensor network oriented to the IPv6 protocol, and is an intermediate layer defined in the network layer.

It provides upward access support of the MAC layer to the IPv6 protocol, and implements control network construction, topology, fragment reassembly, header compression, and determination. Sexual support, etc. The adaptation layer frame format is mainly described for the IPv6 protocol.

6.2 Frame format

6.2.1 General frame format

The adaptation layer frame is the payload portion of the MPDU, and each adaptation layer frame is composed of two basic parts. a frame header and a payload. Adaptation layer header package In the form of a stack, the stack consists of headers with different header types and header fields, according to different functional requirements.

The adaptation layer general frame format includes a frame header stack of the adaptation layer encapsulation and an adaptation layer payload. Wherein, the adaptation layer frame header includes a frame header Type field and corresponding frame header field. The frame header stack of the adaptation layer encapsulation is described as a specific order field, in a certain order, according to The second is the Mesh header, the broadcast header, the slice header, and the dispatch header. As shown in Figure 3.

6.2.2 Frame Head Type

The adaptation layer header type field is 8 bits, and each frame header type is determined by the corresponding type field. As shown in Table 1.

6.2.3 Mesh Head

The adaptation layer Mesh header consists of a Mesh type field and a corresponding Mesh header field. Mesh type field is divided by the highest two points Do not set to 1 and 0 to decide. The structure of the adaptation layer Mesh header frame is shown in Figure 4.

The adaptation layer Mesh header frame structure includes a V field, an F field, a remaining hop count field, a source address field, and a destination address field in sequence.

The corresponding meaning of each field is shown in Table 2.

6.2.4 Broadcast Header (BC0 Header)

The adaptation layer broadcast header follows the Mesh header and consists of a broadcast (BC0) type field and a corresponding broadcast (BC0) header field. BC0 The type field is determined by setting the highest two bits to 0 and 1. The adaptation layer broadcast header frame structure is shown in FIG. 5.

The BC0 header field is the LBC0 sequence number. The BC0 serial number is incremented by 1 each time a new Mesh broadcast or multicast packet is sent. Duplicate packets are detected and suppressed.

6.2.5 Fragment reorganization

Fragmentation reorganization includes.

a) fragment retransmission request header The fragment retransmission request header is used for the fragment receiving direction to send information to the fragment sender to feed back the lost fragment. Fragment retransmission request header format Figure 6 shows. The header type identifier bit "11001" of the slice retransmission request header is set according to the allocation of the original header dispatch value. Minute The slice retransmission request header has two formats. When the number of lost fragments does not exceed 15, the fragment retransmission request header format should be as shown in Figure 6a). Show. When the number of lost fragments exceeds 15, the fragment retransmission request header format should be as shown in Figure 6b).

b) fragment retransmission response header format The slice retransmission response header is used to retransmit lost fragments. The fragment retransmission response header format is shown in Figure 7.

The header type identifier of the slice retransmission request header is set to "11101" according to the allocation of the original header dispatch value.

6.2.6 Dispatch header

The scheduling header type description value and the scheduling header are as shown in FIG. 8.

The frame format of the scheduling header is shown in Figure 9.

Packet Length--- Indicates the length of the original packet (in octets). Fragment label --- indicates the label of the fragment.

MFSUM --- indicates the number of lost fragments. The value of this field ranges from 0 to 15. It can indicate that there are 15 fragments lost. The value of this field is "0" and "30" is not used to indicate the number of lost fragments, but is used to indicate the success of the reorganization and the abandonment of the reorganization. When 0 and 30 appear in the domain When you do not follow any missing fragment number fields.

MFNUM --- indicates the number of the lost fragment. When there are multiple shards lost, the order of the missing shard numbers is arranged from small to large. In order to distribute The sender retransmits in the order in which the fragments are sent. When all the missing shards are completely filled, if the data is fragmented The length of the request header is not aligned with the boundary of the integer octet, and "0" is padded at the end to make the header length an integer octet. […]