分类： 嵌入式
2016-11-24 19:03:24
Controller 有完整的路由表，能够和所有的设备通信。分为primary和second primary，根据功能类型分为Protable、Static类型。Static可以具有SUS、SIS（Z-Wave firmware version v3.4之后才能支持）功能，防止路由表丢失，以及更新路由表的机制，看下面的两张图比较容易理解。
Slave 没有路由表，只能回复给它发送消息的节点。不能主动向其它节点发送数据。
Routing slave 没有路由表，相应的传输路径由controller生成后传输给它，通过这个路径进行信息传输。
The routing slave is capable of initiating communication. Examples of a routing slave could be a wall control or temperature sensor. If a user activates the wall control, the routing slave sends an “on” command to a lamp (slave).
The routing slave does not have a complete routing table. Frames are sent to destinations configured during association. The association is performed via a controller. If routing is needed for reaching the destinations, it is also up to the controller to calculate the routes.
Portable controllers
The definition of portable controllers implies that this device may change its location in the network freely. It has ability to discover and rediscover its position in the network by pinging the surrounding nodes. Usually portable controllers are battery-operated devices that are used by the user to send commands to the network.
A secondary but important function of the portable controller is to include or exclude devices in the network. Each Z-Wave network should have one primary controller that manages the inclusion/exclusion process and holds the latest network configuration. Other controllers copy this information from the primary controller. The node inclusion operation involves exchanging data between the selected node and the primary controller using low-power transmission. It greatly simplifies network configuration from the user's standpoint but also stipulates that one of the portable controllers assumes the role of the primary controller.
Static controllers
Static controllers assume a fixed position in the network and are powered from the main line. They are always in "listening mode" hence other devices may communicate with them at any time.
In a more elaborate network, a static controller may extend its functionality and become a device for storing the latest network configuration, called Static Update Controller (SUC).
The static controller may even become a primary controller in the network and use portable controllers as proxies to include/exclude other nodes. In that case the static controller is calledSUC ID Server (SIS).
Naturally, static controllers may work as bridges to other elements of the home ecosystem, like TCP/IP network or trivial X10 devices. Interestingly enough, a Z-Wave network may support up to 125 virtual nodes using a dedicated bridge controller(s).
The bridge controller, where the virtual node functionality is implemented, makes it possible to seamlessly migrate to a Z-Wave network in the places where other home automation technologies have already been used. In other words, you can add Z-Wave devices (such as X10 devices) to an existing network and use a bridge controller to provide an interface between the different networks. On the Z-Wave network, the X10 modules look like regular Z-wave nodes, and vice versa. Later you may want to upgrade your system and substitute all X10 devices with Z-Wave modules. This task can be done on a Z-Wave network by simply removing existing virtual nodes and substituting them with real nodes.
Slave devices
Slave devices have much simpler functionality than controllers. They can't initiate transmission unless responding to the controller's request. Therefore, to obtain information from a regular slave device, the controller has to poll the device status at periodic intervals. Slave devices may be used to re-transmit the message; in this case such devices called routing slaves, but they should have main power to be in "listening mode" all the time. Since routing slaves are able to transmit unsolicited messages, such devices may be used where periodical polling is not acceptable, such as in fire or burglar alarms.
If a slave device is intended to be used as a battery-operated sensor that periodically wakes up to communicate with the static controller (as used in motor sensor-type products, for example), it's the developer's responsibility to implement the logic in the controller application that will put the slave into deep-sleep mode for a period of time and to create a matching logic in the slave application to notify the static controller each time the slave wakes up.
Static Update Controller (SUC) and SUC ID Server (SIS)
If there is one primary controller in the network, it will provide its routing table, to every secondary controller included in the network. However, the next time the primary controller includes or excludes a network device, the routing tables of all secondary controllers becomes invalid.
To ensure there is a single updated and valid routing table, the primary controller is the only device allowed to include/exclude devices. Secondary controllers then periodically request a routing table update.
However, for a user-friendly Z-Wave network we would expect that:
· All remote controllers shall be able to include devices and that the routing
· The routing tables of all controllers in the network are kept consistent and an update shall allow every controller to control every device in the network
The best way to accomplish this is to configure a SUC /SIS controller in the network.
The Static Update Controller (SUC) is a special function of a static controller. Most static controllers (a controller with fixed location and mains-powered) can perform as a SUC. However, this functionality normally needs to be activated.
The SUC receives the updated routing table from the primary controller and offers this routing table to all other controllers in the network. Because the SUC is a static controller and therefore always active in the network, any other controller can regularly request an updated routing table from the SUC.
To make sure that all other nodes, particularly other controllers, are aware of the presence of a SUC in the network, the Node ID of an activated SUC is periodically communicated within the network.
Having an active SUC allows a portable controller to perform the role of the primary controller. Every change of the network caused by inclusion or exclusion of a node by the primary controller will be reported to the SUC, this is available to all other controllers, even if the primary controller is not active.
Since most portable controllers are battery-operated and therefore not active all the time, these controllers have to request an updated routing table periodically or at least when woken up, usually by pressing a button.
If the original portable primary controller is lost or damaged, the SUC can assign the primary privilege to a new mobile controller, protecting the user from re-establishing the whole network with a brand new primary controller, and having a different Home ID.
Even having a SUC in the system does not solve the problem that only one controller has the primary privilege and therefore, is the only controller allowed to include new devices. This limitation is overcome by enhancing the SUC functionality by another function called ‘SIS‘ = Static ID Server.
The SIS acts as
depot for new Node IDs that can be assigned by mobile controllers. Having a SIS present in the network allows
every controller in the network to include devices. The controller will just request a new
Node ID from the SIS and assign this new Node ID to the server. The SIS ensures
that Node IDs are only assigned to one node - avoiding conflicts. The only
requirement is that mobile controller has a network connection to the SIS
server in order to request a Node ID.
Using a SIS in your network as a number
of advantages and disadvantages:
· The network topology and information about all nodes are saved in a static controller - much better protected than within a mobile battery-powered device.
· All controllers in a network can include new devices.
· The network configuration and handling becomes very flexible.
· Functionality is only available in Z-Wave firmware version v3.4 and later - network devices with older firmware will not support this configuration.
· The Inclusion controller can only integrate devices if it has a wireless connection to the SIS.
· The SIS represents a “Single Point of Failure”. A damaged SIS could result in a complete new network setup.
Since the SUC/SIS functionality is already included in the firmware of most modern static controllers, or USB dongles, most Z-Wave networks can take advantage of these functions if a static controller is present (as long as you activate it).
A static controller can also be used as a primary controller, as well as having SUC/SIS functionality. This configuration is typical in real networks.
If a SUC controller is present in the network it is able to determine a new position of a slave and update the network’s routing table accordingly. The procedure to achieve this is called “Get Lost –Algorithm” and only works for Routing Slaves (slaves that have some knowledge of the network’s routing information).
A normal slave is not allowed to send unsolicited messages and therefore, can never determine any change of its position in the network. However, Routing slaves are allowed to do this.
If a routing slave sends an unsolicited message that fails, it will assume that its routing table is no longer valid.
As a first step this node will send out a broadcast “cry for help” message to the network. A node that receives this message knows that the sender has found itself in a new location. This node, however, cannot provide the “crying” node with an updated routing table. If this node is a routing slave it will forward the “cry for help” message to the SUC.
The SUC can update its own routing table and assign new routes to the crying node by performing the same steps it would do when including the device. The “cry for help” message is able to auto-heal a network in case a node has been moved.
In order to have a working auto-healing function within the network, the following requirements must to be fulfilled:
· A SUC needs to be present in the network.
· The moved nodes must be a routing slave not a standard slave (to allow unsolicited messaging).
· In the new position there must be at least one routing slave in range.
· The moved node must detect that he was moved. This is only possible if this node sends out an unsolicited message.
Hopefully this has given you an good insight into how to create a stable and robust Z-Wave network.
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Slaves are categorised as “standard” or “routing” slaves. A routing slave includes advanced routing capabilities.
The difference between the three different node types is their knowledge of the network routing table and their ability to send messages to the network.
Controller 有完整的路由表，能够和所有的设备通信。分为primary和second primary，根据功能类型分为Protable、Static类型。Static可以具有SUS、SIS功能。
Slave 知道所有的邻居节点，但没有路由表信息，不能进行路由，只能回复给它发送消息的节点。不能主动向其它节点发送数据。
Routing slave 有部分的路由表（是controller提供给它的），能够和接收到的信息中的节点通信。
Another typical network consists of a static controller - mostly PC software plus Z-Wave USB dongle or an IP gateway together with a number of switches and dimmers.
The static controller is the primary controller and includes all other devices.
Because a static controller is bound to a certain location, the other Z-Wave devices must be included while being in direct range with the static controller. They will typically be installed at their final location after inclusion.
In a larger network several controllers will work together. A static controller is used for the configuration and management of the system and one or several remote controls carry out certain functions in different places.
If a network has multiple controllers, the user needs to determine which of the controllers will be the primary controller.
Inclusion of a static controller is a challenge, if the devices need to be moved to their final location afterwards. A network re-organisation needs to be performed.
Static controllers are usually more reliable and aren’t easily lost. They typically offer backup functions to replace the hardware in case of severe damage.
Remote controls are more vulnerable to damage and loss. Usually remote controls do not offer a backup function. If the primary controller was damaged or lost, a complete re-inclusion of the whole network would need to be performed. However, devices can be included after they were installed, which results in a much more stable network, and no need for network re-organisation.
The choice of the primary controller - static or portable - depends more on your personal preference rather than a technical necessity.
