RFC5826 Chinese Home Automation routingrequirements in Low-power and Lossy Networks

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Home Automation routingrequirements in Low-power and Lossy Networks

Routing requirements in the area of furniture automation in low-power lossy networks

1 Introduction

This document addresses the needs of roll's home control and automation applications in this particular area. In the future, many families will have wireless devices with a lot of different functions.

Because roll nodes cover only a limited range of radio frequencies, routing is often required. These devices are typically resource-constrained, such as batteries and storage, that run in an unstable environment. The movement of a person in a house, the switch of a door, or the opening of a microwave can affect the reception of a faint radio signal. This could cause a reliable wireless link to become unreliable at some point in time, but then again usable, which is the term "lossy". All traffic in the roll network is hosted by the IPV6 packet.

The connections in the family sector are extremely consumer-oriented. This means that network nodes are very cost-sensitive, leading to low CPU and low storage resource-constrained environments. At the same time, the physical size is small and the battery capacity is limited, so the sensor node shuts down the transceiver and CPU most of the time. Wireless transceivers tend to use the same energy for listening and sending.

Although this document focuses on wireless networks based on wireless transceivers, home automation networks can also operate with a variety of other links, such as IEEE 802.15.4, Bluetooth, low power WiFi, wired, or other low-power PLCs (power-line Communication) Link. Many low-power link technologies and low-power wireless links have similar characteristics, so this document should also be considered suitable for all such links.

Section2 describes typical cases of home automation applications. Section3 discusses the routing needs of a network of restricted devices in a home network environment.

1.1 Terminology

Roll based routing for low Power lossy networks

Actuator A network node that performs some physical action.

Border Router Connect Roll network to Internet or backbone network

The controller controls the network nodes of the actuators. Control decisions may be based on sensor readings, sensor events, scheduled actions, or commands from the network. If there is sufficient energy, the controller node can participate in Routing network information.

Downstream data transfer direction from a local network (LAN) to a domain network (PAN) device

DR Demand-response. The mechanism by which the user adjusts the energy consumption is the response to the actual energy pricing.

DSM demand-side Management.

RAM Random Access Memory

Upstream data flow direction from pan to LAN

2 Home automation applications

For networked devices with specific needs, home automation applications are presented as a specific part. Historically, such applications have used wired networks or PLCs, but wireless schemes have emerged, which allows existing families to get updates more easily.

To simplify the requirements discussed in Section3, this section lists some typical examples of home automation applications. Most home automation applications tend to run a number of command/response type protocols. Commands come from several places.

2.1 Lighting Applications

A lamp can be opened, not only through a switch on the wall, but also through a mobile node. Wall Switch He himself is both a button and a actuator (exciter; [Computer] executing agency; [Electric] (electromagnet) solenoid; [Machine] actuator). Cases that are frequently encountered when upgrading an existing family of wired connections that are not prepared for automation.

An event may cause many actuators to be activated at the same time.

2.2 Energy conservation and energy consumption optimization

In order to save energy, air conditioners, heaters, curtains and so on, can have timers, motion sensors or remote control through the network or mobile phone.

The grid may be experiencing such a period of time, with the output of wind power exceeding the required power supply. In general this situation occurs more often in the evening.

The use of equipment such as air conditioners, climate control systems and washing machines can be avoided in the time when electricity demand exceeds the available energy supply, to avoid overloading the grid.

This is known as Demand-side Management (DSM). Remote control of home appliances is ideal for this application.

The opening and closing of electrical equipment can also be controlled according to the dynamic energy pricing information of power supply company. This approach, known as Demand-response (DR), is achieved through the use of pricing, reward points and other means to motivate users. For example, washing machines and dishwashers only need to work at low prices. Electric cars can also be recharged at this time.

To achieve effective power savings, energy monitoring applications must ensure that the energy consumption of the roll device is lower than that of the appliance itself.

Most of the appliances are functional, which is ideal for providing reliable, in-routing state resources. Conversely, the battery function node is limited to routing resources, and may only provide reliable routes in some cases.

2.3 Remote control of mobile

In home automation networks, remote control is a typical example of mobile device applications. A state-of-the-art remote control may be used to dim the lights of a restaurant, after meals and after the music has been washed out in the kitchen. The reaction must be fast (controlled in hundreds of milliseconds), or even remote control has moved to a new location. Remote control either communicates with the Home Automation control center or directly with the luminaire or Media Center.

2.4 Adding a new module to the system

Small size. The low-power module may not have a user interface, except for a single button. Therefore, the controller needs an auto-hold process to discover new modules. Includes neighbor detection and unique node ID assignment. The accommodating process should be completed within seconds.

In consumer application space, such as family control, in order to simplify the use of the implementation node is accommodated, do not need to type special code before it is accommodated. An implementation of an acceptable balance between safe and convenient lines that organizes the hold process during normal operation, starts accommodating support before adding a new module, and then closes the process again after adding a new module.

If the assigned unique address is performed by a central controller, it must be able to route a hold request from the join node to the central controller before the node to be joined has been accommodated in the network.

2.5 control of battery operated curtains

In front of consumers, curtains are generally battery-powered because there is no access to the main power. For battery-saving purposes, such actuator nodes are dormant for most of the time. A controller sending commands through a roll device to the actuator node in hibernation will pass the packet to the nearest energy-supply router, but the router may experience a delay until the next wake-up time period before the command is delivered.

2.6 Remote Video surveillance

Remote video monitoring is a fairly classic application in a home network. It provides the ability for end users to get a video stream from a webcam over the network. The video stream may be triggered by the user, after receiving an alarm from a sensor (action or smoke detector), or the user simply wants to check the status of the home through a video.

Note In the previous example, more generally, there will be an internal set-up communication: In the House to detect certain movements, the motion sensor will send the light controller a light command, the network camera to start a video stream, through the network to the end of the user's mobile phone or PDA.

Contrary to other applications, such as industrial sensors, the data is mainly generated in the sensor to the sink node, or conversely, this application involves direct internal device communication between roll devices.

2.7 Health Care

By adding communication capabilities to the device, patients and older people can perform simple tests at home.

Thanks to the online device, a doctor can take care of the patient's health and receive an alarm once a new trend is detected by an automatic oscilloscope.

Routine tests that are presented in a suitable way may allow physicians to establish more accurate diagnoses.

This application may be implemented through wearable devices, frequent detection, automatic transmission of results to a local data sink or through the network.

A more aggressive application category that sends an alert if some alarm conditions are triggered. This application involves family health monitoring. Detection is processed on the device, and reports are sent only when a warning is triggered.

Because wireless and battery power systems are not guaranteed to operate for hundreds of hours, a health care and safety system requires a management-level alarm mechanism for low-energy batteries, dynamic reporting, and so on.

For example, if a blood pressure sensor does not report a new measurement after five minutes beyond the set time, some responsible person must pay attention.

The structure and execution of such a management layer is not within the scope of the routing requirements of this document.

2.7.1 Home Health Report

2.7.2 Home Health Monitoring

2.8 Alarm System

Home security alarm system has a variety of sensors (fire, CO, windows and doors, glass crushing, pressure, emergency buttons, etc.).

Some smoke alarms are battery-powered and installed at high-out. Battery-powered safety devices should be used for routing only in the absence of other alternatives, to avoid battery exhaustion. A battery-depleted smoke alarm does not provide too much security. Also, it is inconvenient to replace the battery for the smoke sensor.

Alarm system applications may have both synchronous and asynchronous behavior, for example, they may be used by the central controller to apply periodic queries (such as periodic updates to the network condition) or they proactively send messages to the control application.

When a node or a group of nodes confirms a dangerous condition (such as intrusion, smoke, fire), it transmits alarm information to the central controller, and the controller automatically forwards it over the Internet or other interactive network nodes (for example, trying to get more detailed information, or letting other nodes turn off alarm events).

Finally, routing through the battery-powered node may be very slow if the node is in most sleep time (they may not be responsible for alarm detection). To ensure fast message delivery and avoid battery exhaustion, routing should be avoided through the hibernation device.

3 Specific routing requirements for home automation applications

Home automation applications have a number of specific routing needs, and a set of cognitive operations for home network applications and systems.

The relevant use case requirements are listed in the following table:

3.1 Based on restricted routing

For convenience and low operating costs, the energy consumption of consumer products must be kept at a very low level in order to achieve a long battery life. This fact means that RAM is limited or even stopped for energy, leaving only hundreds of bytes of RAM available during the sleep period.

The use of battery-powered equipment reduces installation costs and can be installed for devices that do not provide the primary energy supply. On the other hand, in order to be cost effective and efficient, the device must maximize the sleep cycle of less than 1% of duty cycles.

Some devices are awakened only when they respond to an event, such as a button.

Simple battery-powered nodes, such as motion sensors and rain sensors, may not be able to help with routing. Depending on the node type, the node is not always listening, not even listening, or communicating with those pre-configured target nodes. Attempts to communicate with such nodes may take a long time to respond.

Other battery-powered nodes may have the ability to participate in routing. If possible, routing protocols should be routed through the mains-powered node.

Routing protocols must support based on restricted routing, considering node capabilities (CPU, storage, energy level, sleep interval, battery replacement convenience, and security).

3.2 Mobility Support

In a home environment, although most devices are fixed, there are still a variety of mobile devices, such as remote controllers that may be mobile. Some other mobile devices such as wearing health care equipment.

Although the health device delivers measurements that tolerate a few seconds of Route discovery, remote control is irresponsible if the response time to pause music is longer than 0.5 seconds.

On some more extreme occasions, the receiving node may have been moved. such as a cleaning robot or the doorbell sound wireless settings.

A non-responsible node may have the following conditions: 1, error on the node, 2, link error to the node path, 3, a moved node. In the first two cases, you can expect the node to reappear in the same vicinity in the network, but in the latter case it may appear in any location.

3.3 Measurable

For wall switches, plug-in boards, various sensors, video equipment and other devices in modern homes, hundreds of devices constitute a home automation network, and most of them are low-power devices.

Routing protocols need to be able to support basic home deployments and must be able to support at least 250 devices in one network. Further, the protocol should be extensible to support more complex and future deployments of large quantities of equipment.

3.4 Convergence Time

A wireless home automation network suffers from a variety of destabilizing factors, due to changes in signal strength, human movement, and others.

Measure the transmission of a packet, providing the following convergence time requirements.

The routing protocol must converge for 0.5 seconds if no node moves (section 3.2 for mobility).

The routing protocol must converge at 4 seconds, if the node moves, re-establishes the connection, and the operator can tolerate the time, for example when moving a remote control unit.

In the above two cases, convergence means that the initiating node has received a response from the destination node.

3.5 Manageability

The ability of the home network to support automatic configuration is very important. Indeed, most end users do not have the professional skills to perform advanced configuration and problem handling. Therefore, the routing protocol designed for home networks must provide a set of features, including the 0 Configuration routing protocol for the new node network. At the point of view of routing, 0 configuration means that a node relies on itself to get an address and join the network with little or no human involvement.

3.6 Stability

If a node is prone to error when compared to other nodes in the network, then this node should not be the first choice for traffic routing.

4 Traffic Forms

According to the design philosophy of the home network, the wall switch is configured to directly control the private luminaire or in another case, all the wall switches send control commands to the Center light control computer, and the center sends control command-line related devices.

In a distributed system, traffic tends to be multipoint to multipoint. In a centralized system, it combines multi-point and point-to-multipoint.

The wall switch only generates traffic when activated, and typically occurs one to 10 times in one hours.

Remote control has a similar transfer mode as a wall switch, but is more frequently activated in some deployments.

Temperature/air and pressure/rain sensors The data frame is sent when the measurement data is sent by a user query or preconfigured at a fixed interval (typically a few minutes). When the action is detected for the first time, the motion sensor typically sends a data frame, sending other frames when the idle time (Idle period) segment has disappeared without action. The highest transmission frequency depends on the sensor's idle time. Sometimes a timer will trigger a frame transfer when an extended period of time without a state change has elapsed.

All the frames sent in the example above are fairly short, with a general load of less than five bytes. Frame loss and interference from other transmitters can lead to retransmission. In all cases, a few byte-length confirmation frames are used.

5 Safety considerations

Like every network case, Llns also exposes a way out of security threats that need to be addressed. The wireless and distributed nature of these networks increases the range of potential routing security threats. This is further amplified, facing resource-constrained nodes, so that the deployment of resource-intensive routing security policies is blocked. A feasible routing security policy should be lightweight enough to be implemented on all LLNS nodes. During the design process, these issues require special attention in order to facilitate the commercialization of an attractive deployment.

An attacker could spy on, replay, or originate from any message to a node, attempting to manipulate or malfunction the routing function.

To mitigate this problem, Lln must be able to authenticate the new node before the routing decision process allows it to join. The routing protocol must support message integrity.

An example of a more in-depth routing security problem is the abnormal behavior of nodes, which prevents a behavior that is self-absorbed, such as not following network rules or forwarding useless or erroneous packets.

Other important issues can occur in the context of denial of service attacks, malicious address space allocations, changeable address announcements, and wrong neighbors. Routing protocols should support the issue of defending against Dos attacks and other LLN nodes that attempt to maliciously cause the routing mechanism to consume a limited resource excessively. For example, by constructing a forwarding loop or by causing an over-routing protocol to manage traffic.

These LLN networks have the desirable self-configuration and self-organizing features that bring additional routing security considerations. The mechanism must correctly reject any node that attempts to maliciously exploit self-configuration and self-organizing features. For example, these attacks may attempt to cause DOS, deplete the energy of resource-constrained devices, or hijack the routing mechanism. A node must be authenticated to a trusted node of an already associated Lln, before the node joins self-organizing and self-configuring. A node that has been authenticated and associated to the LLN must refuse to allocate resources to any peer that is not certified. The routing protocol must deny service to any node that does not have a trust with Hc-lln.

In a family-controlled environment, it is unlikely that a network is being spied on, and ease of use is also important. Therefore, the network key may be exposed during a short period of time to accommodate the new node.

Electronic door locks and other important applications should apply End-to-end application security on top of the network transportsecurity.

Due to low computational power and a small amount of energy resources, LLNS nodes cannot resist any attacks from high-energy rogue nodes (such as laptops and high-power wireless transceivers). However, the damage to the entire network should be commensurate with the number of nodes. For example, an intruder who controls a single node should not have a service that denies the entire network.

In general, routing protocols should support the implementation of routing security. Such an implementation should include, for example, man-in-the-middle attacks, replay attacks, information tampering, etc.

The routing security scheme will have an impact on routing protocol selection. Finally, the proposed routing protocol in the LLNS context must support authentication and integrity measures, while security (routing security) measures should be supported.

6 acknowledgements

7 References

Translation: FRANK_JB 20150508

The level is limited, not in the wrong place, please refer to the original document in detail

RFC5826 Chinese Home Automation routingrequirements in Low-power and Lossy Networks

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