摘要:
A communication system in which multiple protocols and proxy services are executed by an access point. In one embodiment of the invention, GVRP and GMRP registrations are combined in a single packet when a wireless device roams to a different VLAN. In addition, outbound GVRP and GMRP multicast messages are handled by an access point (also referred to as a GVRP and GMRP “gateway”) such that the wireless device is not burdened with the associated computational overhead. In a further embodiment, a wireless device may dynamically switch between a VLAN-aware state and a VLAN-unaware state depending on the nature of a detected access point. For example, if a relevant access point supports GVRP, the wireless device may operate as a VLAN terminal. If a wireless device is not attached to an access point with a matching VLAN ID, the wireless device sends and receives VLAN tagged frames. If a wireless device configured with a VLAN ID is attached to an access point with a matching VLAN ID, or if the wireless device is attached to a non-VLAN access point, then the wireless device may send and receive raw/untagged frames. In addition to the gateways described below, the ability of a wireless device to detect when it can send untagged frames is considered novel. In another embodiment of the invention, a special ID that is different than the native VLAN ID for a switch port is used for VLAN-unaware devices. This allows such devices that do not issue tagged frames to belong to a single VLAN ID.
摘要:
A mobile customer service station operating within a wireless multi-hop communication network includes a console on a wheeled chassis. The console carries and houses a number of components which are used in merchandising operations to conclude customer purchase transactions. The items supported externally on the console are a printer for printing purchase receipts, customer credit charge agreements and records of transactions, and a magnetic card reader for reading information from a magnetic stripe of a customer's credit card. In one embodiment, the operation of the printer, credit card reader and the cash drawer is controlled by a multi-function control unit located within an enclosure of the console. The control unit is electrically powered by a self-contained power source which is preferably a deep cycle rechargeable battery. The console also houses a transceiver unit which under the control of the control unit is capable of interactive communication with a premises network. In another embodiment, the mobile service station comprises an access device which participates with a variety of peripherals at the station in a lower power communication LAN, while providing higher power communication to other network devices via a premises network with routing via a wireless spanning tree configuration.
摘要:
A hierarchical communication system is described in which two wireless local area networks exhibiting substantially different characteristics are employed to link inherently portable or mobile computer devices. A series of radio base stations make up a infrastructure network. The infrastructure network and at least one portable computer device make up the first local area network. The communication on the first local area network is accomplished by spread spectrum frequency hopping communication A second local area network allows for radio communication between a portable computer device and peripheral devices with built-in transceivers utilized by the portable computer device. The communication in each local area network is controlled by a reservation access communication protocol. The communication protocol facilitates frequency hopping synchronization and supports adaptive data rate selection based upon the quality of communication on the communication channel. The communication protocol prevents interference between communication on the first local area network and communication on the second local area network. In a premises LAN, a series of radio base stations and a backbone LAN make up an infrastructure network. The infrastructure network and at least one mobile computing device make up a higher-power LAN, utilizing a frequency hopping protocol. A lower-power LAN allows for radio communication between a mobile computing device and peripheral devices, utilizing a single-frequency spread spectrum protocol. A vehicular LAN provides for short-range communication between a vehicle terminal and a portable terminal. When out of direct RF range of the premises LAN, the vehicle terminal maintains indirect communication when necessary with the premises LAN via one of several alternate RF channels. A microprocessor, located inside radio units which participate in multiple LAN's, selects the appropriate protocol, frequency band and power level for communicating through the network.
摘要:
Improved apparatus for a radio communication system having a multiplicity of mobile transceiver units selectively in communication with a plurality of base transceiver units which, in turn, communicate with one or more host computers for storage and manipulation of data collected by bar code scanners or other collection means associated with the mobile transceiver units. A network controller and an adapter which has a simulcast and sequential mode provide selective interface between host computers and base transceivers. A scheme for routing data through the communication system is also disclosed wherein the intermediate base stations are organized into an optimal spanning-tree network to control the routing of data to and from the RF terminals and the host computer efficiently and dynamically. Additionally, redundant network and communication protocol is disclosed wherein the network utilizes a polling communication protocol which, under heavy loaded conditions, requires that a roaming terminal wishing to initiate communication must first determine that the channel is truly clear by listing for an entire interpoll gap time. In a further embodiment, a criterion used by the roaming terminals for attaching to a given base station reduces conflicts in the overlapping RF regions of adjacent base stations.
摘要:
A power-save QSTA notifies an Access Point (AP) that its operating in a automatic power-save delivery (APSD) mode and negotiates a periodic wakeup schedule and a scheduled startup time with the AP. Wakeup times are synchronized with the 802.11 Timer Synchronization Function (TSF). The AP automatically sends frames to the QSTA when it determines the QSTA is in an awake state, otherwise downlink frames are buffered. The AP uses a combination poll+EDCF access method wherein at the start of each wakeup period the AP sends a poll to the QSTA, the poll having a flag that indicates to the QSTA if the AP has a downlink fame buffered for the QSTA. In addition, a Proxy ARP Server in an AP maintains IP/MAC bindings for associated clients so that when the AP receives a proxy ARP request for a client, the AP may respond for the client.
摘要:
Disclosed herein is a redundant network and communication protocol at least including host computers, RF base stations, and roaming terminals. The network may utilize a polling communication protocol such that under heavy traffic conditions, a roaming terminal wishing to initiate communication may be required to determine whether the channel is clear by listening for an entire interpoll gap time. When a hidden terminal is communicating, the roaming terminal may conclude that the communication is taking place upon receiving a polling frame directed to the hidden terminal from the normally silent base station. Inherent redundancy techniques may be used with a spanning tree approach for determining the most efficient pathways from a source to a destination and ensuring that the network adapts to spatial changes or breakdowns within the network.
摘要:
A hierarchical communication system, arranged in a spanning tree configuration, is described in which wired and wireless communication networks exhibiting substantially different characteristics are employed in an overall scheme to link portable or mobile computing devices. Copies of data, program code and processing resources are migrated from their source toward requesting destinations based on request frequency, communication link costs and available local storage and/or processing resources. Each appropriately configured network device acts as an active participant in network migration. In addition, portable two-dimensional (2-D) code reading terminals are configured to wirelessly communicate compressed 2-D images toward stationary access servers that identify the code image through decoding and through comparison with a database of images that have previously been decoded and stored.
摘要:
An apparatus and a method for routing data in a radio data communication system having one or more host computers, one or more intermediate base stations, and one or more RF terminals organizes the intermediate base stations into an optimal spanning-tree network to control the routing of data to and from the RF terminals and the host computer efficiently and dynamically. Communication between the host computer and the RF terminals is achieved by using the network of intermediate base stations to transmit the data.
摘要:
A method providing quality of service during a contention period. A tiered access protocol enables an Access Point to act as a channel arbitrator and gain control a channel during a contention period. The Enhanced Access Point waits a specified amount of time after before taking control of a channel for either transmitting an outbound frame or initiating Polled-Contention Free Bursts. In addition, a method for increasing the time span between Delivery Traffic Indication Message beacons by tracking when Wireless Stations are able to receive messages and instantly delivering messages to those Wireless Stations.
摘要:
A protocol that enables an 802 mobile host to obtain a “home IP address,” and other configuration parameters via DHCP or BOOTP, while attached to either its home subnet or a foreign subnet. Inner and outer encapsulation headers are used to forward DHCP messages from a DHCP server outbound through a “forward tunnel,” to a mobile host on a foreign subnet and are also used to forward DHCP messages from a mobile host on a foreign subnet inbound through a “reverse tunnel” to the home subnet. A mobile host must add an inner encapsulation header to inbound DHCP packets with the source IP address set to 0 to indicate that the packet is from a mobile host that does not have a registered home IP address. Outer encapsulation headers contain the home address and the care-of address for the mobile host.