LLC – IEEE 802.2 Logical Link Control
Regarding secure communications, the MAC sublayer offers facilities which can be harnessed by upper layers to achieve the desired level of security. The definition of the network layers is based on the OSI model ; although only the lower layers are defined in the standard, interaction with upper layers is intended, possibly using an IEEE The first one is the full-function iwee FFD.
First standard amendments by these groups were released in April The structure can be extended as a generic mesh network whose nodes are cluster tree networks with a local coordinator for each cluster, in addition to the global coordinator. Whatever the case, 8022 a device is unable to process a frame at a given time, it simply does not confirm its reception: Namely, within each PAN domain, communications will probably 8022 short identifiers.
It can be contrasted with other approaches, such as Wi-Fiwhich offer more bandwidth and require more power.
The physical layer PHY ultimately provides the data transmission service, as well as the interface to the physical layer management entitywhich 082.2 access to every layer management function and maintains a database of information on related personal area networks.
Retrieved 9 December This creates a reliable data transfer mechanism at the Data Link Layer. November Learn how and when to remove this template message. Networks are thus formed by groups of devices separated by suitable distances. Because the predicted environment of these devices demands maximization of battery life, the protocols tend to favor the methods which lead to it, implementing periodic checks for pending messages, the frequency of which depends on application needs.
They are meant to serve as the basis for ad hoc networks capable of 8022. self-management and organization. Note that the IEEE It also controls frame validation, guarantees time slots and handles node associations. Devices are conceived to interact with each other over a conceptually simple wireless network. These are meant to be extremely simple devices with very modest resource and communication requirements; due to this, they can only communicate with FFDs and can never act as coordinators.
Data transfers from the coordinator usually follow device requests: Thus, the PHY manages the physical RF transceiver and performs channel selection and energy and signal management functions. Please improve this by adding secondary or tertiary sources. From Wikipedia, the free encyclopedia. It can serve as the coordinator of a personal area network just as it may function as a common node.
Devices also include dtudy management functions such as link quality and energy srudy. After that, other devices can join the network, which is fully independent from all other star networks. This stuxy was last edited on 21 Mayat This section of the compendium discusses the types of Logical Link Control behavior that you might observe with your protocol analyzer and details how to isolate and describe problems that may occur. The connection between the network interface card and the rest of the communications system is through a structure called a Service Access Point SAP, pronounced like the sap from which maple syrup is made.
Standards. IEEE , , , | Networks & Communications
As already mentioned, the main identifying feature of IEEE Higher-layer processes may specify keys to perform symmetric cryptography to protect the payload and restrict it to a group of devices or just a point-to-point link; these groups of devices can be specified in access control lists. Views Read Edit View history.
In addition to this secure mode, there is another, insecure MAC mode, which allows access control lists  merely as a means to decide on the acceptance of frames according to their presumed source. Confirmation messages may be optional under certain circumstances, in which case a o assumption is made.