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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.
1. In a network having wireless communication capability for providing communication pathways within a premises in which the network comprises a plurality of wireless portable terminals and a plurality of bridges, the plurality of bridges being located in spaced relation within the premises and comprising at least two wireless bridges, a particular bridge of the plurality of bridges comprising:
a wireless bridge that is configured to form a spanning tree to maintain communication pathways between any two of the plurality of wireless portable terminals as the wireless portable terminals roam within the premises,
wherein the wireless bridge is configured to communicate with at least one of the plurality of wireless portable terminals when selected by the at least one of the plurality of the wireless portable terminals.
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7. In a network having wireless communication capability to provide communication pathways within a premises in which the network comprises a first wireless portable terminal, a second terminal and a plurality of bridges that are located in spaced relation within the premises, a particular bridge of the plurality of bridges comprising:
a wireless bridge that is configured to form wireless communication pathways between at least one other of the plurality of bridges to permit the first wireless portable terminal and the second terminal to communicate as the first wireless portable terminal and the second terminal roam within the premises,
wherein the wireless bridge is configured to communicate with the first wireless portable terminal or the second terminal when selected by the first wireless portable terminal or the second terminal.
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wherein the wireless bridge is in the network in which the network comprises a host computer, and
wherein, in the network, the wireless communication pathways do not involve the host computer.
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12. In a network having spread spectrum wireless communication capability that provide communication pathways in which the network comprises wireless mobile communication devices and a plurality of bridges, the plurality of bridges comprising at least two wireless bridges, a particular bridge of the plurality of bridges comprising a wireless bridge that is configured to form a spanning tree to maintain communication pathways between any two of the wireless mobile communication devices as the wireless mobile communication devices roam, the wireless bridge being configured to communicate with at least one of the wireless mobile communication devices when selected by the at least one of the wireless mobile communication devices.
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24. In a network having spread spectrum wireless communication capability to provide communication pathways in which the network comprises a first wireless mobile communication device, a second wireless mobile communication device and a plurality of bridges, a particular bridge of the plurality of bridges comprising: a wireless bridge that is configured to form wireless communication pathways with at least one other of the plurality of bridges to permit the first wireless mobile communication device and the second wireless mobile communication device to communicate as the first wireless mobile communication device and the second wireless mobile communication device roam, the wireless bridge being configured to communicate with the first wireless mobile communication device or the second wireless mobile communication device when selected by the first wireless mobile communication device or the second wireless mobile communication device.
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The present application is a continuation of application U.S. application Ser. No. 09/542,424, filed Apr. 4, 2000, now U.S. Pat. No. 6,826,165 which is a continuation of application U.S. application Ser. No. 09/066,125, filed Apr. 24, 1998, now U.S. Pat. No. 6,046,992, which is a continuation of U.S. application Ser. No. 08/543,838, filed Feb. 16, 1996, now abandoned, which is a continuation of U.S. application Ser. No. 08/410,592, filed Mar. 27, 1995, now U.S. Pat. No. 5,504,746, which is a continuation of U.S. application Ser. No. 07/968,990, filed Oct. 30, 1992, now abandoned, which is a continuation-in-part of both U.S. application Ser. No. 07/769,425, filed Oct. 1, 1991 now abandoned and PCT Application Serial No. PCT/US92/08610, filed Oct. 1, 1992.
The above-referenced applications are hereby incorporated herein by reference in their entirety.
In a typical radio data communication system having one or more host computers and multiple RF terminals, communication between a host computer and an RF terminal is provided by one or more base stations. Depending upon the application and the operating conditions, a large number of these base stations may be required to adequately serve the system. For example, a radio data communication system installed in a large factory may require dozens of base stations in order to cover the entire factory floor.
In earlier RF (Radio Frequency) data communication systems, the base stations were typically connected directly to a host computer through multi-dropped connections to an Ethernet communication line. To communicate between an RF terminal and a host computer, in such a system, the RF terminal sends data to a base station and the base station passes the data directly to the host computer. Communicating with a host computer through a base station in this manner is commonly known as hopping. These earlier RF data communication systems used a single-hop method of communication.
In order to cover a larger area with an RF data communication system and to take advantage of the deregulation of the spread-spectrum radio frequencies, later-developed RF data communication systems are organized into layers of base stations. As in earlier RF data communications systems, a typical system includes multiple base stations which communicate directly with the RF terminals and the host computer. In addition, the system also includes intermediate stations that communicate with the RF terminals, the multiple base stations, and other intermediate stations. In such a system, communication from an RF terminal to a host computer may be achieved, for example, by having the RF terminal send data to an intermediate station, the intermediate station send the data to a base station, and the base station send the data directly to the host computer. Communicating with a host computer through more than one station is commonly known as a multiple-hop communication system.
Difficulties often arise in maintaining the integrity of such multiple-hop RF data communication systems. The system must be able to handle both wireless and hard-wired station connections, efficient dynamic routing of data information, RF terminal mobility, and interference from many different sources.
The present invention solves many of the problems inherent in a multiple-hop data communication system. The present invention comprises an RF Local-Area Network capable of efficient and dynamic handling of data by routing communications between the RF Terminals and the host computer through a network of intermediate base stations.
In one embodiment of the present invention, the RF data communication system contains one or more host computers and multiple gateways, bridges, and RF terminals. Gateways are used to pass messages to and from a host computer and the RF Network. A host port is used to provide a link between the gateway and the host computer. In addition, gateways may include bridging functions and may pass information from one RF terminal to another. Bridges are intermediate relay nodes which repeat data messages. Bridges can repeat data to and from bridges, gateways and RF terminals and are used to extend the range of the gateways.
The RF terminals are attached logically to the host computer and use a network formed by a gateway and the bridges to communicate with the host computer. To set up the network, an optimal configuration for conducting network communication spanning tree is created to control the flow of data communication. To aid understanding by providing a more visual description, this configuration is referred to hereafter as a "spanning tree" or "optimal spanning tree".
Specifically, root of the spanning tree are the gateways; the branches are the bridges; and non-bridging stations, such as RF terminals, are the leaves of the tree. Data are sent along the branches of the newly created optimal spanning tree. Nodes in the network use a backward learning technique to route packets along the correct branches.
One object of the present invention is to route data efficiently, dynamically, and without looping. Another object of the present invention is to make the routing of the data transparent to the RF terminals. The RF terminals, transmitting data intended for the host computer, are unaffected by the means ultimately used by the RF Network to deliver their data.
It is a further object of the present invention for the network to be capable of handling RF terminal mobility and lost nodes with minimal impact on the entire RF data communication system.
In the preferred embodiment, the host computer 10 is an IBM 3090, the network controller 14 is a model RC3250 of the Norand Corporation, the data communication link 16 is an Ethernet link, the nodes 20, 22, 24, 40, 42, 44, 46, 48, 50 and 52 are intelligent base transceiver units of the type RB4000 of the Norand Corporation, and the RF terminals 100, 102, 104, 106, 108, 110, 112, 114, 116, 118 and 120 are of type RT1100 of the Norand Corporation.
The optimal spanning tree, which provides the data pathways throughout the communication system, is stored and maintained by the network as a whole. Each node in the network stores and modifies information which specifies how local communication traffic should flow. Optimal spanning trees assure efficient, adaptive (dynamic) routing of information without looping.
To initialize the RF data communication system, the gateway 20 and the other nodes are organized into an optimal spanning tree rooted at the gateway 20. To form the optimal spanning tree, in the preferred embodiment the gateway 20 is assigned a status of ATTACHED and all other bridges are assigned the status UNATTACHED. The gateway 20 is considered attached to the spanning tree because it is the root node. Initially, all other bridges are unattached and lack a parent in the spanning tree. At this point, the attached gateway node 20 periodically broadcasts a specific type of polling packet referred to hereafter as "HELLO packets". The HELLO packets can be broadcast using known methods of communicating via radio frequency (RF) link or via a direct wire link. In the preferred embodiment of the present invention, the RF link is comprised of spread-spectrum transmissions using a polling protocol. Although a polling protocol is preferred, a carrier-sense multiple-access (CSMA), busy-tone, or any other protocol might also manage the communication traffic on the RF link.
HELLO packets contain 1) the address of the sender, 2) the hopping distance that the sender is from the root, 3) a source address, 4) a count of nodes in the subtree which flow through that bridge, and 5) a list of system parameters. Each node in the network is assigned a unique network service address and a node-type identifier to distinguish between different nodes and different node types. The distance of a node from the root node is measured in hops times the bandwidth of each hop. The gateway root is considered to be zero hops away from itself.
By listening to the HELLO messages, bridges can learn which nodes are attached to the spanning tree. At a block 205, the bridge responds to a HELLO packet received by sending an ATTACH.request packet to the device that sent the received HELLO packet. The ATTACH.request packet is thereafter forwarded towards and to the root node which responds by sending an ATTACH.response packet back down towards and to the bridge.
The bridge awaits the ATTACH.response packet at a block 207. Upon receipt of the ATTACH.response packet, at a block 209, the bridge enters an ATTACHED state. Thereafter, at a block 211, the bridge begins periodically broadcasting HELLO packets and begins forwarding or relaying packets received. Specifically, between HELLO packet broadcasts, the bridge listens for HELLO, DATA, ATTACH.request and ATTACH.response packets broadcast by other devices in the communication network. Upon receiving such a packet, the bridge branches to a block 213. At the block 213, if the bridge detects that it has become detached from the spanning tree the bridge will branch back to the block 203 to establish attachment. Note that although the illustration in
If at the block 213 detachment has not occurred, at a block 214, the bridge determines if the received packet is a HELLO packet. If so, the bridge analyzes the contents of the HELLO packet at a block 215 to determine whether to change its attachment point in the spanning tree. In a preferred embodiment, the bridge attempts to maintain attachment to the spanning tree at the node that is logically closest to the root node.
The logical distance, in a preferred embodiment, is based upon the number of hops needed to reach the root node and the bandwidth of those hops. The distance the attached node is away from the root node is found in the second field of the HELLO message that is broadcast. In another embodiment of the present invention, the bridges consider the number of nodes attached to the attached node as well as the logical distance of the attached node from the root node. If an attached node is overloaded with other attached nodes, the unattached bridge may request attachment to the less loaded node, or to a more loaded node as described above in networks having regions of substantial RF overlap. In yet another embodiment, to avoid instability in the spanning tree, the bridge would only conclude to change attachment if the logical distance of the potential replacement is greater than a threshold value.
If no change in attachment is concluded, at a block 217 the bridge branches back to the block 211. If a determination is made to change attachment, a DETACH packet is sent to the root as illustrated at a block 219. After sending the DETACH packet, the bridge branches back to the block 205 to attach to the new spanning tree node. Note that the order of shown for detachment and attachment is only illustrative and can be reversed.
Referring back to the block 214, if the received packet (at block 211) is not a HELLO packet, the bridge branches to a block 221 to forward the received packet through the spanning tree. Afterwards, the bridge branches back to the block 211 to continue the process.
Specifically, once attached, the attached bridge begins broadcasting HELLO packets (at the block 211) seeking to have all unattached bridges (or other network devices) attach to the attached bridge. Upon receiving an ATTACH.request packet, the bridge forwards that packet toward the root node (through the blocks 211, 213, 214 and 221. On its path toward the root, each node records the necessary information of how to reach requesting bridge. This process is called "backward learning" herein, and is discussed more fully below. As a result of the backward learning, once the root node receives the ATTACH.request packet, an ATTACH.response packet can be sent through the spanning tree to the bridge requesting attachment.
After attaching to an attached node, the newly attached bridge (the child) must determine its distance from the root node. To arrive at the distance of the child from the root node, the child adds the broadcast distance of its parent from the root node to the distance of the child from its parent. In the preferred embodiment, the distance of a child from its parent is based on the bandwidth of the data communication link. For example, if the child attaches to its parent via a hard-wired link (data rate 26,000 baud), then the distance of that communication link might equal, for example, one hop. However, if the child attaches to its parent via an RF link (data rate 9600 baud), then the distance of that communication link might correspondingly be equal 3 hops. The number of the hop corresponds directly to the communication speed of the link. This may not only take into consideration baud rate, but also such factors as channel interference.
Initially, only the root gateway node 20 is broadcasting HELLO messages and only nodes 40, 42 and 44 are within range of the HELLO messages broadcast by the gateway. Therefore, after the listening period has expired, nodes 40, 42 and 44 request attachment to the gateway node 20. The unattached nodes 40, 42, and 44 send ATTACH.request packets and the attached gateway node 20 acknowledges the ATTACH.request packets with local ATTACH.confirm packets. The newly attached bridges are assigned the status ATTACHED and begin broadcasting their own HELLO packets, looking for other unattached bridges. Again, the remaining unattached nodes attempt to attach to the attached nodes that are logically closest to the root node. For example, node 48 is within range of HELLO messages from both nodes 40 and 42. However, node 40 is three hops, via an RF link, away from the gateway root node 20 and node 42 is only one hop, via a hard-wired link, away from the gateway root node 20. Therefore, node 48 attaches to node 42, the closest node to the gateway root node 20.
The sending of HELLO messages, ATTACH.request packets and ATTACH.confirm packets continues until the entire spanning tree is established. In addition, attached bridges may also respond to HELLO messages. If a HELLO message indicates that a much closer route to the root node is available, the attached bridge sends a DETACH packet to its old parent and an ATTACH.request packet to the closer node. To avoid instability in the system and to avoid overloading any given node, an attached bridge would only respond to a HELLO message if the hop count in a HELLO packet is greater than a certain threshold value, CHANGE_THRESHOLD. In the preferred embodiment, the value of the CHANGE_THRESHOLD equals 3. In this manner, an optimal spanning tree is formed that is capable of transmitting data without looping.
Nodes, other than the gateway root node, after acknowledging an ATTACH.request packet from a previously unattached node, will send the ATTACH.request packet up the branches of the spanning tree to the gateway root node. As the ATTACH.request packet is being sent to the gateway root node, other nodes attached on the same branch record the destination of the newly attached node in their routing entry table. When the ATTACH.request packet reaches the gateway root node, the gateway root node returns an end-to-end ATTACH.confirm packet.
After the spanning tree is initialized, the RF terminals listen for periodically broadcasted Hello packets to determine which attached nodes are in range. After receiving HELLO messages from attached nodes, an RF terminal responding to an appropriate poll sends an ATTACH.request packet to attach to the node logically closest to the root. For example, RF terminal 110 is physically closer to node 44. However, node 44 is three hops, via an RF link, away from the gateway root node 20 and node 42 is only one hop, via a hard-wired link, away from the gateway root node 20. Therefore, RF terminal 110, after hearing HELLO messages from both nodes 42 and 44, attaches to node 42, the closest node to the gateway root node 20. Similarly, RF terminal 114 hears HELLO messages from nodes 48 and 50. Nodes 48 and 50 are both four hops away from the gateway root node 20. However, node 48 has two RF terminals 110 and 112 already attached to it while node 50 has only one RF terminal 116 attached to it. Therefore, RF terminal 114 will attach to node 50, the least busy node of equal distance to the gateway root node 20. Attaching to the least busy node proves to be the most efficient practice when the communication system has little overlap in the RF communication regions. In another embodiment, however, instead of attaching to the least busy node of equal distance to the gateway root node 20, the attachment is established with the busiest node.
The attached node acknowledges the ATTACH.request and sends the ATTACH.request packet to the gateway root node. Then, the gateway root node returns an end-to-end ATTACH.confirm packet. In this manner, the end-to-end ATTACH.request functions as a discovery packet enabling the gateway root node, and all other nodes along the same branch, to learn the address of the RF terminal quickly. This process is called backward learning. Nodes learn the addresses of terminals by monitoring the traffic from terminals to the root. If a packet arrives from a terminal that is not contained in the routing table of the node, an entry is made in the routing table. The entry includes the terminal address and the address of the node that sent the packet. In addition, an entry timer is set for that terminal. The entry timer is used to determine when RF terminals are actively using the attached node. Nodes maintain entries only for terminals that are actively using the node for communication. If the entry timer expires due to lack of communication, the RF terminal entry is purged from the routing table.
The RF links among the RF terminals, the bridges, and the gateway are often lost. Therefore, a connection-oriented data-link service is used to maintain the logical node-to-node links. In the absence of network traffic, periodic messages are sent and received to ensure the stability of the RF link. As a result, the loss of a link is quickly detected and the RF Network can attempt to establish a new RF link before data transmission from the host computer to an RF terminal is adversely affected.
Communication between terminals and the host computer is accomplished by using the resulting RF Network. To communicate with the host computer, an RF terminal sends a data packet in response to a poll from the bridge closest to the host computer. Typically, the RF terminal is attached to the bridge closest to the host computer. However, RF terminals are constantly listening for HELLO and polling messages from other bridges and may attach to, and then communicate with, a bridge in the table of bridges that is closer to the particular RF terminal.
Under certain operating conditions, duplicate data packets can be transmitted in the RF Network. For example, it is possible for an RF terminal to transmit a data packet to its attached node, for the node to transmit the acknowledgement frame, and for the RF terminal not to receive the acknowledgement. Under such circumstances, the RF terminal will retransmit the data. If the duplicate data packet is updated into the database of the host computer, the database would become corrupt. Therefore, the RF Network of the present invention detects duplicate data packets. To ensure data integrity, each set of data transmissions receives a sequence number. The sequence numbers are continuously incremented, and duplicate sequence numbers are not accepted.
When a bridge receives a data packet from a terminal directed to the host computer, the bridge forwards the data packet to the parent node on the branch. The parent node then forwards the data packet to its parent node. The forwarding of the data packet continues until the gateway root node receives the data packet and sends it to the host computer. Similarly, when a packet arrives at a node from the host computer directed to an RF terminal, the node checks its routing entry table and forwards the data packet to its child node which is along the branch destined for the RF terminal. It is not necessary for the nodes along the branch containing the RF terminal to know the ultimate location of the RF terminal. The forwarding of the data packet continues until the data packet reaches the final node on the branch, which then forwards the data packet directly to the terminal itself.
Communication is also possible between RF terminals. To communicate with another RF terminal, the RF terminal sends a data packet to its attached bridge. When the bridge receives the data packet from a terminal directed to the host computer, the bridge checks to see if the destination address of the RF terminal is located within its routing table. If it is, the bridge simply sends the message to the intended RF terminal. If not, the bridge forwards the data packet to its parent node. The forwarding of the data packet up the branch continues until a common parent between the RF terminals is found. Then, the common parent (often the gateway node itself) sends the data packet to the intended RF terminal via the branches of the RF Network.
During the normal operation of the RF Network, RF terminals can become lost or unattached to their attached node. If an RF terminal becomes unattached, for whatever reason, its routing entry is purged and the RF terminal listens for HELLO or polling messages from any attached nodes in range. After receiving HELLO or polling messages from attached nodes, the RF terminal sends an ATTACH.request packet to the attached node closest to the root. That attached node acknowledges the ATTACH.request and sends the ATTACH.request packet onto the gateway root node. Then, the gateway root node returns an end-to-end ATTACH.confirm packet.
Bridges can also become lost or unattached during normal operations of the RF Network. If a bridge becomes lost or unattached, all routing entries containing the bridge are purged. The bridge then broadcasts a HELLO.request with a global bridge destination address. Attached nodes will broadcast HELLO packets immediately if they receive an ATTACH.request packet with a global destination address. This helps the lost node re-attach. Then, the bridge enters the LISTEN state to learn which attached nodes are within range. The unattached bridge analyzes the contents of broadcast HELLO messages to determine whether to request attachment to the broadcasting node. Again, the bridge attempts to attach to the node that is logically closest to the root node. After attaching to the closest node, the bridge begins broadcasting HELLO messages to solicit ATTACH.requests from other nodes or RF terminals.
The spread-spectrum system provides a hierarchical radio frequency network of on-line terminals for data entry and message transfer in a mobile environment. The network is characterized by sporadic data traffic over multiple-hop data paths consisting of RS485 or ethernet wired links and single-channel direct sequenced spread spectrum links. The network architecture is complicated by moving, hidden, and sleeping nodes. The spread spectrum system consists of the following types of devices:
Terminal controller—A gateway which passes messages from a host port to the RF network; and which passes messages from the network to the host port. The host port (directly or indirectly) provides a link between the controller and a "host" computer to which the terminals are logically attached.
Base station—An intermediate relay node which is used to extend the range of the controller node. Base station-to-controller or base station-to-base station links can be wired or wireless RF.
Terminal—Norand RF hand-held terminals, printers, etc. In addition, a controller device has a terminal component.
The devices are logically organized as nodes in an (optimal) spanning tree, with the controller at the root, internal nodes in base stations or controllers on branches of the tree, and terminal nodes as (possibly mobile) leaves on the tree. Like a sink tree, nodes closer to the root of the spanning tree are said to be "downstream" from nodes which are further away. Conversely, all nodes are "upstream" from the root. Packets are only sent along branches of the spanning tree. Nodes in the network use a "BACKWARD LEARNING" technique to route packets along the branches of the spanning tree.
Devices in the spanning tree are logically categorized as one of the following three node types:
A controller device contains a terminal node(s) and a bridge node. The bridge node is the root node if the controller is functioning as the root bridge. A base station contains a bridge node. A terminal device contains a terminal node and must have a network interface function. A "bridging entity" refers to a bridge node or to the network interface function in a terminal.
The basic requirements of the system are the following.
a) Wired or wireless node connections.
b) Network layer transparency.
c) Dynamic/automatic network routing configuration.
d) Terminal mobility. Terminals should be able to move about the RF network without losing an end-to-end connection.
e) Ability to accommodate sleeping terminals.
f) Ability to locate terminals quickly.
g) Built-in redundancy. Lost nodes should have minimal impact on the network.
h) Physical link independence. The bridging algorithm is consistent across heterogeneous physical links.
The software for the spread-spectrum system is functionally layered as follows.
Medium Access Control (MAC)
The MAC layer is responsible for providing reliable transmission between any two nodes in the network (i.e. terminal-to-bridge). The MAC has a channel access control component and a link control component. The link control component facilitates and regulates point-to-point frame transfers in the absence of collision detection. The MAC channel access control component regulates access to the network. Note that herein, the MAC layer is also referred to as the Data Link layer.
Bridging Layer
The bridging layer, which is also referred to herein as the network layer, has several functions as follows.
1. The bridging layer uses a "HELLO protocol" to organize nodes in the network into an optimal spanning tree rooted at the root bridge. The spanning tree is used to prevent loops in the topology. Interior branches of the spanning tree are relatively stable (i.e. controller and relay stations do not move often). Terminals, which are leaves on the spanning three, may become unattached, and must be reattached, frequently.
2. The bridging layer routes packets from terminals to the host, from the host to terminals, and from terminals to terminals along branches of the spanning tree.
3. The bridging layer provides a service for storing packets for SLEEPING terminals. Packets which cannot be delivered immediately can be saved by the bridging entity in a parent node for one or more HELLO times.
4. The bridging layer propagates lost node information throughout the spanning tree.
5. The bridging layer maintains the spanning tree links.
6. The bridging layer distributes network interface addresses.
Logical Link Control Layer
A logical link control layer, also known herein as the Transport layer herein, is responsible for providing reliable transmission between any two nodes in the network (i.e., terminal-to-base station). The data-link layer provides a connection-oriented reliable service and a connectionless unreliable service. The reliable service detects and discards duplicate packets and retransmits lost packets. The unreliable services provides a datagram facility for upper layer protocols which provide a reliable end-to-end data path. The data-link layer provides ISO layer 2 services for terminal-to-host application sessions which run on top of an end-to-end terminal-to-host transport protocol. However, the data-link layer provides transport (ISO layer 4) services for sessions contained within the SST network.
Higher Layers
For terminal-to-terminal sessions contained within the SST network, the data-link layer provides transport layer services and no additional network or transport layer is required. In this case, the MAC, bridging, and data-link layers discussed above can be viewed as a data-link layer, a network layer, and a transport layer, respectively. For terminal-to-host-application sessions, higher ISO layers exist on top of the SST data-link layer and must be implemented in the terminal and host computer, as required. This document does not define (or restrict) those layers. This document does discuss a fast-connect VMTP-like transport protocol which is used for transient internal terminal-to-terminal sessions.
Specifically, a network layer has several functions, as follows.
1) The network layer uses a "hello protocol" to organize nodes in the network into an optimal spanning tree rooted at the controller. (A spanning tree is required to prevent loops in the topology.) Interior branches of the spanning tree are relatively stable (i.e., the controller and base stations do not move often). Terminals, which are leaves on the spanning tree, become unattached, and must be reattached frequently.
2) The network layer routes messages from terminals to the host, from the host to terminals, and from terminals to terminals along branches of the spanning tree.
3) The network layer provides a service for storing messages for SLEEPING terminals. Messages which cannot be delivered immediately can be saved by the network entity in a parent node for one or more hello times.
4) The network layer propagates lost node information throughout the spanning tree.
5) The network layer maintains the spanning tree links in the absence of regular data traffic.
A transport layer is responsible for establishing and maintaining a reliable end-to-end data path between transport access points in any two nodes in the network. The transport layer provides unreliable, reliable and a transaction-oriented services. The transport layer should be immune to implementation changes in the network layer.
The responsibilities of the transport layer include the following.
1) Establishing and maintaining TCP-like connections for reliable root-to-terminal data transmission.
2) Maintaining VMTP-like transaction records for reliable transient message passing between any two nodes.
3) Detecting and discarding duplicate packets.
4) Retransmitting lost packets.
Layers 1 through 4 are self-contained within the Norand RF network, and are independent of the host computer and of terminal applications. The session layer (and any higher layers) are dependent on specific applications. Therefore, the session protocol (and higher protocols) must be implemented as required. Note that a single transport access point is sufficient to handle single sessions with multiple nodes. Multiple concurrent sessions between any two nodes could be handled with a session identifier in a session header.
Network address requirements are as follows. DLC framed contain a hop destination and source address in the DLC header. network packets contain an end-to-end destination and a source address in the network header. Transport messages do not contain an address field; instead, a transport connection is defined by network layer source and destination address pairs. Multiple transport connections require multiple network address pairs.
The transport header contains a TRANSPORT ACCESS POINT identifier. DLC and network addresses are consistent and have the same format. Each node has a unique LONG ADDRESS which is programmed into the node at the factory. The long address is used only to obtain a SHORT ADDRESS from the root node.
The network entity in each node obtains a SHORT ADDRESS from the root node, which identifies the node uniquely. The network entity passes the short address to the DLC entity. Short addresses are used to minimize packet sizes.
Short addresses consist of the following. There is: an address length bit (short or long).
a spanning tree identified.
a node-type identifier. Node types are well known.
a unique multi-cast or broadcast node identifier.
The node-identifier parts of root addresses are well known and are constant. A default spanning tree identifier is well known by all nodes. A non-default spanning tree identifier can be entered into the root node (i.e., by a network administrator) and advertised to all other nodes in "hello" packets. The list of non-default spanning trees to which other nodes can attach must be entered into each node.
A node-type identifier of all 1's is used to specify all node types. A node identifier of all 1's is used to specify all nodes of the specified type. A DLC identifier of all 0's is used to specify a DLC entity which does not yet have an address. The all-0's address is used in DLC frames that are used to send and receive network ADDRESS packets. (The network entity in each node filters ADDRESS packets based on the network address.)
Short-address allocation is accomplished as follows. Short node identifiers of root nodes are well known. All other nodes must obtain a short node identifier from the root. To obtain a short address, a node send an ADDRESS request packet to the root node. The source addresses (i.e., DLC and network) in the request packet are LONG ADDRESSES. The root maintains an address queue of used and unused SHORT ADDRESSES. If possible, the root selects an available short address, associates the short address with the long address of the requesting node, and returns the short address to the requesting node in an ADDRESS acknowledge packet. (Note that the destination address in the acknowledge packet is a long address.)
A node must obtain a (new) short address initially and whenever an ADDRESS-TIMEOUT inactivity period expires without having the node receive a packet from the network entity in the root.
The network entity in the root maintains addresses in the address queue in least recently used order. Whenever a packet is received, the source address is moved to the end of the queue. The address at the head of the queue is available for use by a requesting node if it has never been used or if it has been inactive for a MAX-ADDRESS-LIFE time period.
MAX-ADDRESS-LIFE must be larger than ADDRESS-TIMEOUT to ensure that an address is not in use by any node when it becomes available for another node. If the root receives an ADDRESS request from a source for which an entry exists in the address queue, the root simply updates the queue and returns the old address.
The network layer organizes nodes into an optimal spanning tree with the controller at the root of the tree. (Note that the spanning three identifier allows two logical trees to exist in the same coverage area.) Spanning tree organization is facilitated with a HELLO protocol which allows nodes to determine the shortest path to the root before attaching to the spanning tree. All messages are routed along branches of the spanning tree.
Nodes in the network are generally categorized as ATTACHED or UNATTACHED. Initially, only the root node is attached. A single controller may be designated as the root, or multiple root candidates (i.e. controllers) may negotiate to determine which node is the root. Attached bridge nodes and root candidates transmit "HELLO" packets at calculated intervals. The HELLO packets include:
a) the source address, which includes the spanning tree ID).
b) a broadcast destination address.
c) a "seed" value from which the time schedule of future hello messages can be calculated.
d) a hello slot displacement time specifying an actual variation that will occur in the scheduled arrival of the very next hello message (the scheduled arrival being calculated from the "seed").
e) the distance (i.e., path cost) of the transmitter from the host. The incremental portion of the distance between a node and its parent is primarily a function of the type of physical link (i.e., ethernet, RS485, RF, or the like). If a signal-strength indicator is available, connections are biased toward the link with the best signal strength. The distance component is intended to bias path selection toward (i.e., wired) high-speed connections. Setting a minimum signal strength threshold helps prevent sporadic changes in the network. In addition, connections can be biased to balance the load (i.e., the number of children) on a parent node.
f) a pending message list. Pending message lists consist of 0 or more destination-address/message-length pairs. Pending messages for terminals are stored in the terminal's parent node.
g) a detached-node list. Detached-node lists contain the addresses of nodes which have detached from the spanning tree. The root maintains two lists. A private list consists of all detached node addresses, and an advertised list consists of the addresses of all detached nodes which have pending transport messages. The addresses in the hello packet are equivalent to the advertised list.
An internal node learns which entries should be in its list from hello messages transmitted by its parent node. The root node builds its detached-node lists from information received in DETACH packets. Entries are included in hello messages for DETACH-MSG-LIFE hello times.
Attached notes broadcast "SHORT HELLO" messages immediately if they receive an "HELLO.request" packet with a global destination address; otherwise, attached nodes will only broadcast hello messages at calculated time intervals in "hello slots." Short hello messages do not contain a pending-message or detached-node list. Short hello messages are sent independently of regular hello messages and do not affect regular hello timing.
Unattached nodes (nodes without a parent in the spanning tree) are, initially, in an "UNATTACHED LISTEN" state. During the listen state, a node learns which attached base station/controller is closest to the root node by listening to hello messages. After the listening period expires an unattached node sends an ATTACH.request packet to the attached node closest to the root. The attached node immediately acknowledges the ATTACH.request, and send the ATTACH.request packet onto the root (controller) node. The root node returns the request as an end-to-end ATTACH.confirm packet. If the newly-attached node is a base station, the node calculates its link distance and adds the distance to the distance of its parent before beginning to transmit hello messages.
The end-to-end ATTACH.request functions as a discovery packet, and enables the root node to learn the address of the source node quickly. The end-to-end ATTACH.request, when sent from a node to the root, does not always travel the entire distance. When a downstream node receives an ATTACH.request packet and already has a correct routing entry for the associated node, the downstream node intercepts the request and returns the ATTACH.confirm to the source node. (Note that any data piggy-backed on the ATTACH.request packet must still be forwarded to the host.) This situation occurs whenever a "new" path has more than one node in common with the "old" path.
The LISTEN state ends after MIN_HELLO hello time slots if hello messages have been received from at least one node. If no hello messages have been received the listening node waits and retries later.
An attached node may respond to a hello message from a node other than its parent (i.e., with an ATTACH.request) if the difference in the hop count specified in the hello packet exceeds a CHANGE-THRESHOLD level.
Unattached nodes may broadcast a GLOBAL ATTACH.request with a multi-cast base station destination address to solicit short hello messages from attached base stations. The net effect is that the LISTEN state may (optionally) be shortened. (Note that only attached base station or the controller may respond to ATTACH.requests.) Normally, this facility is reserved for base stations with children and terminals with transactions in progress.
ATTACH.requests contain a (possibly empty) CHILD LIST, to enable internal nodes to update their routing tables. ATTACH.requests also contain a "count" field which indicates that a terminal may be SLEEPING. The network entity in the parent of a SLEEPING terminal con temporarily store messages for later delivery. If the count field is non-zero, the network entity in a parent node will store pending messages until 1) the message is delivered, or 2) "count" hello times have expired.
Transport layer data can be piggy-backed on an attached request packet from a terminal. (i.e., an attach request/confirm can be implemented with a bit flag in the network header of a data packet.)
Network Layer Routing
All messages are routed along branches of the spanning tree. Base stations "learn" the address of terminals by monitoring traffic from terminals (i.e., to the root). When a base station receives (i.e., an ATTACH.request) packet, destined for the root, the base station creates or updates an entry in its routing table for the terminal. The entry includes the terminal address, and the address of the base station which sent the packet (i.e., the hop address). When a base station receives an upstream packet (i.e., from the root, destined for a terminal) the packet is simply forwarded to the base station which is in the routing entry for the destination. Upstream messages (i.e., to a terminal) are discarded whenever a routing entry does not exist. Downstream messages (i.e., from a terminal to the root) are simply forwarded to the next downstream node (i.e., the parent in the branch of the spanning tree.
TERMINAL-TO-TERMINAL COMMUNICATIONS is accomplished by routing all terminal-to-terminal traffic through the nearest common ancestor. In the worst case, the root is the nearest common ancestor. A "ADDRESS SERVER" facilitates terminal-to-terminal communications (see below).
DELETING INVALID ROUTING TABLE ENTRIES is accomplished in several ways: connection oriented transport layer ensures that packets will arrive from nodes attached to the branch of the spanning tree within the timeout period, unless a node is disconnected.)
2) Whenever the DLC entity in a parent fails RETRY MAX times to send a message to a child node, the node is logically disconnected from the spanning tree, with one exception. If the child is a SLEEPING terminal, the message is retained by the network entity in the parent for "count" hello times. The parent immediately attempts to deliver the message after it sends its next hello packet. If, after "count" hello times, the message cannot be delivered, then the child is logically detached from the spanning tree. Detached node information is propagated downstream to the root node, each node in the path of the DETACH packet must adjust its routing tables appropriately according to the following rules: a) if the lost node is a child terminal node, the routing entry for the terminal is deleted and a DETACH packet is generated, b) if the node specified in DETACH packet is a terminal and the node which delivered the packet is the next hop in the path to the terminal, then the routing table entry for the terminal is deleted and the DETACH packet is forwarded, c) if the lost node is a child base station node then all routing entries which specify that base station as the next hop are deleted and a DETACH packet is generated for each lost terminal.
When DETACH packets reach the root node, they are added to a "detached list." Nodes remain in the root node's detached list until a) the node reattaches to the spanning tree, or b) the list entry times out. The detached list is included in hello messages and is propagated throughout the spanning tree.
For example, if a terminal detaches and reattaches to a different branch in the spanning tree, all downstream nodes in the new branch (quickly) "learn" the new path to the terminal. Nodes which were also in the old path change their routing tables and no longer forward packets along the old path. At least one node, the root, must be in both the old and new path. A new path is established as soon as an end-to-end attach request packet from the terminal reaches a node which was also in the old path.
4) A node (quickly) learns that it is detached whenever it receives a hello message, from any node, with its address in the associated detached list. The detached node can, optionally, send a global ATTACH.request, and then enters the UNATTACHED LISTEN state and reattaches as described above. After reattaching, the node must remain in a HOLD-DOWN state until its address is aged out of all detached lists. During the HOLD-DOWN state the node ignores detached lists.
5) A node becomes disconnected and enters the UNATTACHED LISTEN state whenever HELLO-RETRY-MAX hello messages are missed from its parent node.
6) A node enters the ATTACHED LISTEN state whenever a single hello message, from its parent, is missed. SLEEPING terminals remain awake during the ATTACHED LISTEN state. The state ends when the terminal receives a data or hello message from its parent. The terminal becomes UNATTACHED when a) its address appears in the detached list of a hello message from an ode other than its parent, or b) HELLO-RETRY-MAX hello messages are missed. The total number of hello slots spend in the LISTEN state is constant.
If a node in the ATTACHED LISTEN state discovers a path to the root which is CHANGE-THRESHOLD shorter, it can attach to the shorter path. Periodically, SLEEPING terminals must enter the ATTACHED LEARN state to discovery any changes (i.e., shorter paths) in the network topology.
Hello Synchronization.
All attached non-terminal nodes broadcast periodic "hello" messages in discrete "hello slots" at calculated intervals. Base station nodes learn which hello slots are busy and refrain from transmitting during busy hello slots.
A terminal refrains from transmitting during the hello slot of its parent node and refrains from transmitting during message slots reserved in a hello message.
The hello message contains a "seed" field used in a well-known randomization algorithm to determine the next hello slot for the transmitting node and the next seed. The address of the transmitting node is used as a factor in the algorithm to guarantee randomization. Nodes can execute the algorithm i times to determine the time (and seed) if the i-the hello message from the transmitter.
After attached, a base station chooses a random initial seed and a non-busy hello slot and broadcasts a hello message in that slot. The base station chooses succeeding hello slots by executing the randomization algorithm. If an execution of the algorithm chooses a busy slot, the next free slot is used and a hello "displacement" field indicates the offset from a calculated slot. Cumulative delays are not allowed (i.e., contention delays during the i hello transmission do not effect the time of the i+1 hello transmission).
HELLO-TIME and HELLO-SLOT-TIME values are set by the root node and flooded throughout the network in hello messages. The HELLO-SLOT-TIME value must be large enough to minimize hello contention.
A node initially synchronizes on a hello message from its parent. A SLEEPING node can power-down with an active timer interrupt to wake it just before the next expected hello message. The network entity in base station nodes can store messages for SLEEPING nodes and transmit them immediately following the hello messages. This implementation enables SLEEPING terminals to receive unsolicited messages. (Note that the network layer always tries to deliver messages immediately, before storing them.) Retries for pending messages are transmitted in a round-robin order when messages are pending for more than one destination.
Note that a child node that misses i hello messages, can calculate the time of the i+1 hello message.
Transport Layer Theory and Implementation Notes.
The transport layer provides reliable, unreliable, and transaction-oriented services. Two types of transport connections are defined: 1) a TCP-like transport connection may be explicitly requested for long-lived connections or 2) a VMTP-like connection-record may be implicitly set up for transient connections. In addition, a connectionless service is provided for nodes which support an end-to-end transport connection with the host computer.
The interfaces to the next upper (i.e., application) layer include:
CONNECT (access_point, node_name)
LISTEN (access_point)
UNITDATA (access_point, node_name, buffer, length)
SEND (handle, buffer, length)
RECEIVE (handle, buffer, length)
CLOSE (handle)
The "handle" designates the connection type, and is the connection identifier for TCP-like connections.
SEND messages require a response from the network node (root or terminal) to which the message is directed.
UNITDATA messages do not require a response. UNITDATA is used to send messages to a host which is capable of supporting end-to-end host-to-terminal transport connections.
Because the network layer provides an unreliable service, the transport layer is required to detect duplicate packets and retransmit lost packets. Detecting duplicates is facilitated by numbering transport packets with unambiguous sequence numbers.
Transport Connections.
TCP-like transport connections are used for message transmission over long-lived connections. The connections may be terminal-to-root or terminal-to-terminal (i.e., base stations are not involved in the transport connection).
TCP-like transport connections are established using a 3-way handshake. Each end selects its initial sequence number and acknowledges the other end's initial sequence number during the handshake. The node which initiates the connection must wait a MAX-PACKET-LIFE time, before requesting a connection, to guarantee that initial sequence numbers are unambiguous. Sequence numbers are incremented modulo MAX-SEQ, where MAX-SEQ is large enough to insure that duplicate sequence numbers do not exist in the network. Packet types for establishing and breaking connections are defined as in TCP.
A TCP-like connection is full-duplex and a sliding window is used to allow multiple outstanding transport packets. An ARQ bit in the transport header is used to require an immediate acknowledgment from the opposite end.
VMTP-like connections are used for transient messages (i.e. terminal-to-terminal mail messages). VMTP-like connection records are built automatically. A VMTP-like connection record is built (or updated) whenever a VMTP-like transport message is received. The advantage is that an explicit connection request is not required. The disadvantage is that longer and more carefully selected sequence numbers are required. A VMTP-like connection is half-duplex. (A full-duplex connection at a higher layer can be built with two independent half-duplex VMTP-like connections.) Acknowledgments must be handled by higher layers.
Transport connections are defined by the network end-to-end destination and source addresses.
A MAX_TP_LIFE timeout is associated with transport connections. Transport connection records are purged after a MAX_TP_LIFE time expires without activity on the connection. The transport entity in a terminal can ensure that its transport connection will not be lost by transmitting an empty time-fill transport packet whenever TP_TIMEOUT time expires without activity.
The transport entity in a node stores messages for possible retransmission. Note that retransmissions may not always follow the same path (primarily) due to moving terminals and the resulting changes in the spanning tree. For example, the network entity in a parent node may disconnect a child after the DLC entity reports a message delivery failure. The child will soon discover that it is detached and will reattach to the spanning tree. Now when the transport entity (i.e. in the root) re-sends the message, it will follow the new path.
Transport Message Timing and Sleeping Terminals.
The transport entity in a terminal calculates a separate timeout for SEND and TRANSACTION operations. Initially, both timeouts are a function of the distance of the terminal from the root node.
A TCP-like algorithm is used to estimate the expected propagation delay for each message type. Messages, which require a response, are retransmitted if twice the expected propagation time expires before a response is received. SLEEPING terminals can power down for a large percentage of the expected propagation delay before waking up to receive the response message. Note that missed messages may be stored by the network layer for "count" hello times.
Medium Access Control (MAC) Theory and Implementation Notes.
Access to the network communications channel is regulated in several ways: executing the full CSMA algorithm (see MAC layer above). The sender retransmits unacknowledged messages until a RETRY_MAX count is exhausted.
The retry time of the DLC must be relatively short so that lost nodes can be detected quickly. When the DLC layer reports a failure to deliver a message to the network layer, the network layer can 1) save messages for SLEEPING terminals for later attempts, or 2) DETACH the node from the spanning tree. Note that most lost nodes are due to moving terminals.
The node identifier part of the DLC address is initially all 0's for all nodes except the root node. The all 0's address is used by a node to send and received data-link frames until a unique node identifier is passed to the DLC entity in the node. (The unique node identifier is obtained by the network entity.)
Address Resolution.
Well-known names too are bound to network addresses in several ways:
Base station-to-base station traffic could also be routed through the controller if the backward learning algorithm included base station nodes. (Each base station would simply have to remember which direction on its branch of the spanning tree to send data directed toward another base station.)
The possibility of multiple controllers is kept open by including a spanning-tree identifier in address fields. Each controller defines a unique spanning tree. A node can be in more than one spanning tree, with separate network state variables defined for each.
Thus, the preferred embodiment of the present invention describes an apparatus and a method of efficiently routing data through a network of intermediate base stations in a radio data communication system.
In alternate embodiments of the present invention, the RF Networks contain multiple gateways. By including a system identifier in the address field of the nodes, it is possible to determine which nodes are connected to which networks.
As is evident from the description that is provided above, the implementation of the present invention can vary greatly depending upon the desired goal of the user. However, the scope of the present invention is intended to cover all variations and substitutions which are and which may become apparent from the illustrative embodiment of the present invention that is provided above, and the scope of the invention should be extended to the claimed invention and its equivalents.
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Bishop's College School
BCS is a world renowned English boarding and day high school located in the heart of Quebec. BCS offers its students numerous opportunities to get involved both locally and internationally. Students choose to be a part of the BCS community because of its picturesque campus, small class sizes, devoted teachers and staff, and the array of available activities and sports. Students who come to BCS forge unforgettable memories and ever lasting friendships.


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CORDIA – Administrators at Lotts Creek Community School say a newly-acquired grant could help local communities build a more sustainable future.
The school was recently awarded funding through Grow Appalachia, an initiative begun in Berea in 2009 that aims to decrease the impact of food insecurity in Appalachia, with partner sites in Kentucky, Tennessee, and West Virginia. The overall goal is to increase knowledge and capacity for gardening in the region, something that is increasingly being lost with the younger generation of people, noted Jeff Combs, director of the wellness program at Lotts Creek Community School.
"We have kind of lost the sense of gardening and how to garden, especially part of my generation," said Combs, who is 31. "It's kind of a lost thing; kids don't know anything about gardening."
There are a few reasons for this decline in growing food locally, Combs said, including the ease with which more processed and less healthy foods can now be obtained cheaply through super markets.
With these grant funds, however, Combs said he expects that local children will benefit from an increased knowledge in gardening because it provides the tools to teach younger generations about the positive effects of growing their own food. The program will also represent a boon for the older generation of people who may wish to continue gardening, but are no longer able to prepare the soil.
"We're trying to bring gardening back to a generation that's no longer able, plus the generation that's never done it," Combs explained, adding the school will be able to not only till garden plots, but also provide fertilizer and seeds.
The program at Lotts Creek has already signed up 20 people to participate in the local service community, which includes Lotts Creek, Clear Creek, and Vicco. Combs noted that there are requirements for the participants, including that they attend a few educational classes and record their growth each month.
Another benefactor of the program will be the school's food pantry, which serves 190 local families. Combs is donating the use of an acre of his own land in Perry County for a gardening plot, which in turn will supply the food pantry with fresh produce. And what isn't taken from the pantry will be used in the after school program.
Combs said he views this program as one of the best the school will offer, because if it is successful it will not only help secure a more sustainable future for local families, but also a healthier one as it could guide people away from eating more processed foods. And while these foods may be cheaper than raw fruits and vegetables now, they may not remain so inexpensive. According to the latest Marketbasket Survey conducted by the Kentucky Farm Bureau Federation, food prices in Kentucky decreased by 1 percent in the state in the fourth quarter of 2012, but that followed a 2 percent increase the previous quarter.
"It's all about getting people back into gardening and sustainability, especially with their food cost being so high," Combs said. "Part of it is also the healthy aspect. You can't eat stuff that's processed. It's a killer. We want people going back to eating more healthy food."
Additionally, there are even instances, while not common, where raw fruits and vegetables purchased at stores have been contaminated with E. coli or some other potentially harmful agent. Growing food in your own back yard could help reduce the likelihood of contamination, Combs explained.
"Nothing can be healthier than something you grow in your back yard," he said.
There is money available to help people with year round gardening, including construction of high tunnels and even raising chickens and goats, Combs said. At present, the program at Lotts Creek has signed its limit of participants, but as the grant is renewable each year, there would be a requirement to sign up more people if the grant is renewed. So, there is room for expansion next year.
In the meantime, Combs said he has been busy purchasing the necessary equipment and supplies to get the program up and running, and he's looking forward to the local benefits that it could provide.
"I think it's going to be one of the best things we do," he said.


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After the winter storm hit our area many events that were scheduled to take place did not happen as planned. Santa's Workshop, that was supposed to take place Friday and Saturday, was completely canceled and at this time is not planned to be rescheduled. Other events that will not take place include: pictures with Santa, Santa's Little Helpers Christmas pageant and Rudolph bingo.
The $1000 Shop Local drawing, Christmas parade and fireworks display will be rescheduled but at this time no date has been set.


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1/17 - Heidi Leigh Swope, 24, 100 Garden Spot Lane, Autryville, possession of meth, possession of drug paraphernalia, possession of a Schedule II controlled substance; and simple possession of a Schedule VI controlled substance. Bond $10,000; court date Feb. 1.
1/17 - Wallace McNeil, 46, 112 Allen Drive, Erwin, habitual impaired driving and failure to appear on simple assault. Bond $5,000; court date Feb. 1
1/17 - Richard Sessoms of West Old Stage Road, Autryville, reported that someone broke into his own and took a 46-inch TV valued at $450. An estimated $50 damage was also reported to an AC window unit.


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A 14-year-old student reported that someone took his cellphone from his gym locker while he was in PE class at Aiken High School on Jan. 30.
A 39-year-old Aiken man was detained for simple possession of marijuana on Monday after someone reported seeing him smoking marijuana in a vehicle in front of Kroger on Whiskey Road. Officers found a pipe used to smoke the drug and a jar filled with a green, leafy substance inside his vehicle.
An unknown man took a case of beer from the Kangaroo on York Street on Tuesday.
An Aiken man reported that someone woke him up banging loudly on his back door about 6 a.m. on Tuesday. He heard glass break and found the window on his back door shattered, but didn't see anyone outside.
An unknown woman entered Tractor Supply Company on Whiskey Road on Tuesday, hid a pair of pants in her purse and then left the store without paying for the pants.
Two teenage girls were accused of trying to shoplift several clothing items from Target on Whiskey Road on Tuesday. They returned the items after being confronted by a store employee and were placed on trespass notice for the store.
A Graniteville man reportedly shot himself in the right ring finger while he was putting his gun away in his home on Wednesday.
Burglaries were reported to the Aiken County Sheriff's Office on Blanchard Road in North Augusta, Eastbrook Park Circle in Aiken, John Nunn Highway in Salley, Chalk Bed Road in Graniteville, Madison Avenue in Aiken and Powderhouse Road in North Augusta.
Multiple vehicle break-ins were reported on Wagontong Road in Wagener on Wednesday.
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No one man should have all those drinks, etc. A music video by Freddie Wong.
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Too Many Coverers.Mission: Impossible — Rogue Nation Accomplishes Its Task, Just Not Always That Well
Might as well add (The Rebecca Ferguson Show) to the end.
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She's set to star in Eclipsed, Danai Gurira's play about the Liberian Civil War.The Black Mass Trailer Is Like Being at a Party With Every Actor in Hollywood, All of Whom Want to Show You Their Amazing Boston Accents
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Such an underappreciated genre.Christine Baranski's Favorite The Good Wife Episode Was When She Was Arguing With Oliver Platt About Gay Rights
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Such jumping!Ricki and the Flash Shocker: Meryl's Playing a Republican!
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The sad thing is if the ban we all fear actually passes, Tim will get a few dozen PMs in about June asking if he still has it for sale!
Better start fishing out all those parts ya threw in the canal, they may be worth more than gold someday. Heck, ya could get that Emily chick from Bering Sea Gold to dive for the stuff while you operate the shop vac up top. I'm sure she would appreciate warm water for a change!


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Forty years after the publication of Erich von Däniken's Chariots of the Gods, Philip Coppens revisits the question of whether "ancient aliens" contributed to the birth of human civilization.
©2011 Philip Coppens (P)2011 Tantor
"An important and outstanding contribution." (Erich von Däniken, author of Chariots of the Gods)
"Thoroughlly Enjoyable"
There were many ancient things mentioned which I was unaware existed.
I liked how well the interesting history of ideas over the last 200 years is lain out in the book. It's a great history lesson of people's ideas on ancient things and the evolution of those ideas over time.
Very good narration. Could listen to him all day.
I also like how the author doesn't make any outlandish statements however explains the many possibilities of why and how and let's the reader make up there own mind. All round an excellent book and narration. Highly recommend to anyone interested in ancient history.
"Interesting perspective"
Yes. There is a lot of information covered in this book. I like to investigate on my own, and then return to the book afterwards.
New info along the same subject lines. There is also additional information and new insight on topics discussed in the past.
Kevin Foley is always great!
"great book"
I will keep this short. If you watch Ancient Aliens you will not hear much new int his book, rather expanded ideas. I found they talked about certain things that I wish I could google just to see what they were talking about or where they were.
This is a very heavy book. I found I almost needed to pause it just to digest the info. Overall, I would say if you watch the TV show, maybe skip it. If you are new to these ideas, get this book for sure!
"Rather Interesting..."
I thought I'd read or listened to almost all available info on this subject; however, this book had new information I wasn't aware of and it is well thought out with references.
"Too much Quantity, Not Enough Quality"
I was hoping that this book would be a general overall read on the different aspects of ancient aliens and the evidence that people had gathered over the years. The problem was that while it did do this it also overwhelmed with just to much info.
My main problem with this book was that it tried to cover as many theories, examples of evidence, and ideas as possible but did not give enough information or really go as in depth on each of the topics as I would have preferred. I would have rather the author pick just a few examples and covered those a lot more thoroughly than what he did.
Overall, it was a good book but it just wasn't as helpful as I had hoped it would be. I had no problem with Kevin Foley and his reading though.
"very informative and puts the pieces together"
This has become one of my favorites to listen to at night. Its a keeper.
We were not created by the aliens to be slaves mining gold.
Lots of documentation is offered that takes away the guesswork. It made a lot of sense.
I have an undergraduate degree in philosophy and a Master's Degree in Professional Writing from Maharishi University of Management, am author of THE RELUCTANT VEGETARIAN COOKBOOK, and am an avid reader/listener.
"Some books help one think"
All questions have two sides, and I really liked this book because it provided good data for both. It was fairly presented, kept my attention, and professionally written.
A well researched and very well composed book. Coppens presents the best evidence to support his arguments as well as evidence to counter arguments. He gives his sources as well as how reliable (or not) they are. I learned a great deal of things from this book. If you find this book intriguing and wish to go further - I recommend Graham Hancock's Supernatural as it deals with some of the same content but with more detail.
Where are you from? Everyone wants to know. Will we ever truly know? Maybe we never will maybe we wont.
"An overview with many new& interesting details of"
what could be considered behind-the-scenes information within a community of authors and researchers of similar interests.
Philip Coppens did a great job covering a broad range of mystery topics, explaining the mystery, the history and current explanations, sometimes critically evaluating theories and findings, sometimes disputing an author or researcher's points.
A small percentage of the listeners to this book may have read every book Philip Coppens reviewed and reported on in this book, but it is more likely that this will be a great way to find out what other authors you would like to pursue. Beyond combining all the books he had read to create this overview, Philip Coppens also met some of the authors and researchers at various conferences he attended and shares those experiences as well.
Some of the information in this book goes far beyond combined book reviews on various topics because what is valuable in The Ancient Alien Question audiobook is how Philip Coppens has given a lot of thought to the information he has taken in from books, researchers, and a multitude of experts and has used critical thinking to take apart some ideas and put together some ideas.
For a reader/listener interested in ancient human history, dna, pyramids, Mars, aliens, shamans, Egypt, South America, hidden libraries, underground caves or complexes, as well as the behavior of scientists, religious representatives, and politics, this book has all that and more. Fascinating, and there is enough information to make it worthwhile to listen to again.
Excellent narrator.
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Sticky, it is.
Add a barrel pin removal methods sticky under it.
As far as easing into it the worst that can happen is you fail and F!@K up a $90 pile of parts. most guys can do that trying to fix the kitchen sink. read all the stickys and build coverage you can find. If you have no knowledge of the AK try to get a look at one assembled and maybe ask if they can feild strip it so you at least see how it is susposed to look and work. I remember the first kit I bought I had never even held a AK, there was no info on the net. I stared at the FGC and small parts for a few days. Do a screw build even on a 100% reciver, I have not used the trigger guard plates for sale (always made my own) but I plan on using them from now on as my free time is getting scarce. Ace or true value should have 10-32 screws for the trunion. I cut them down buy drilling and taping a 10-32 hole in a piece of flat bar I screw the screws through the hole and trim of with a die grinder the threads are cleaned up when the screw it removed through the hole
I would not rule out buying a already built AK you can always sell it. gun values very seldom go down. you can add what ever stock or add ons to it latter if you want. most guys build for the fun of it, not nessacrly the cost savings. I build as I like to customize them changing caliburs and making them hunting friendly. If it is not fun why do it saving 35-40 dollars is not worth the trouble.IMOA
Find the Harbor Freight store nearest you, take your banker. Buy what you need. Devorce your wife. Then BUILD, BUILD, BUILD.
Here's a link you need.
Good luck!!!!
So if I read everything correct:
bent blank = hardest
flat = best (as long as you got the tooling or friend with tooling)
laser cut flat = sucks (pain in the ass to weld for the average Joe)
100% most expensive but easy
The only wasted vote is the vote not cast!
Find me on My Space: http://www.myspace.com/drunkardben
+1 I did a lot of research here on the forums before my first build, but having a friend who had done several builds already really helped. He had all the tools and the experience. That was definitely the way to go for the first build. Now I have the confidence to do it on my own (if I ever get the tools).Originally Posted by eubanks
"This episode sent the message that we'll fight them on the beaches, we'll fight them on the hills, but if they kill a few of our soldiers we'll give up and go away." - Mark Bowden (on the Battle of Mogadishu)
I could have bought a complete AK already built for what it cost me to build my first. But I enjoied building it. Kept me out of troubleOriginally Posted by pinball
What size press would be recommended for builds and bending flats?
12 ton is all you need.
As far as the actual pressure required, a 6 ton would probably do it. But the 6 ton press frames are too small for barrel work.
Quick Question:
I'm about to purchase some flats and a flat-bending jig from AK-Builder to use in my 20-ton shop press. Going to be building some Romanian kits - both side-folder and standard stock.
Prior to me making this purchase is there any other flat-bending jig that anyone would recommend? Or flats?
Also, I'm going to purchase some riveting tools. For this purchase I was going to go with Plinker's tools (in the classified section on this forum) based on the unsolicited positive feedback he has received ... and the CD that is included with the purchase.
In summary, would anyone recommend anything different than:
AK-Builder flats
AK-Builder flat-bending jig
Plinker's Riveting Tools
Thanks in advance for your suggestions.
that's top of the line gear.
There is no nonsense so errant that it cannot be made the creed of the vast majority by adequate governmental action. -- Bertrand Russell
"Never attribute to malice that which can be adequately explained by stupidity." Robert J. Hanlon


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Felt and velvet floral appliqués in brilliant hues give this pouf a vivacious, playful texture. Filled with cotton, it's an invitation to sit back, relax, and enjoy.
Luscious fabrics, robust colors, and sublime patterns are the hallmarks of Divine Design's offering. Classic Eastern textiles--kilims, paisleys, ikats--provide a clear inspiration, but these centuries-old themes have been reinvigorated so that they provide a superb complement to all manner of Western decor styles, from traditional to contemporary.


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Thursday, April 4, 2013
A senior and Studio Art major at the College of Charleston, Allison Koch, concepted and created the winning design for Charleston International Film Festival's Spire Award. The award will be given annually during the festival to recognize those who exhibit the very best in the art of filmmaking and writing.
Chosen by the festival's directors from more than a dozen award designs by College of Charleston students, Koch's prototype truly captured the essence of the Spire, which alludes to Charleston's iconic steeple-dotted skyline. Furthermore, the shape of a Spire demonstrates a reach for the skies, something the festival's winning filmmakers and screenwriters truly embody.
Koch, who is from New Jersey, but grew up in North Myrtle Beach said she was influenced by art deco movie theatre architecture. "The geometric, streamlined look seemed to suit the award," Koch said. Her piece evolved, however, as it developed. Koch explained, "the initial form I had in mind is not at all what I felt worked best in the end."
The award will be cast in glass and given out for the first time during the 6th annual Charleston International Film Festival, April 24 - 28.
For having the winning submission, Koch will receive a cash prize of $500.
To learn more about Charleston International Film Festival or buy tickets, visit CharlestonIFF.org.
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Julia Roberts Goad
Staff Writer
A committee of the Mingo County Board of Education that is working toward implementing a drug testing policy for students met and heard from a representative of a company that administers drug testing programs.
The BOE began looking at implementing a drug testing policy earlier in the year with input from the STOP Coalition, a drug abuse education facility based in Gilbert.
Although Mingo does not currently drug screen students, other area school systems, such as Pike and Logan Counties, have a drug testing policy in place. The BOE has looked at policies of other districts to begin to write a policy of its own.
On hand for the committee were several administrators and educators from various Mingo schools as well as Chris Franz of Sport Safe Testing Service.
Franz said his company was started by his father, who was a high school team physician. One of the team's players was shot and killed in a drug deal, which spurred Franz to get involved. He authored a drug testing policy that made it to the Supreme Court. He eventually started the company, and now the company works with school districts across the country. His company has worked with Jackson, Putnam and Cabell Counties in West Virginia.
The U.S. Supreme Court has ruled that public school systems can test students who participate in extracurricular activities, such as sports or band. Using other districts' policies, the Mingo BOE is crafting a policy that will make student athletes eligible for random drug testing, as well as those who drive to school. Testing of students who are in career and technical programs (CTE) such as welding, ProStart culinary and restaurant training and carpentry is also under consideration.
Dreama Dempsey with the BOE said Mingo's drug testing policy would not be punitive.
"We will not be trapping or punishing students who test positive," Dempsey said. "We, under the law, cannot let the procedure affect them academically. We want to deter drug use. We will give students the information and education they need."
Franz presented different types of tests that can be used to screen for drugs, including a urine screen, saliva swab and hair sample. Costs of these test can vary from as little as $3 to as much as $29. Most tests screen for nine drugs, amphetamines, barbiturates, benzodiazepines, cocaine, marijuana, methadone, opiate, phencyclidine, propoxyphene, and alcohol.
But, he said, the key to ensuring accuracy to any testing to to eliminate, as much as possible, human error.
"Once a student's screen comes up positive, that test goes straight to a lab," Franz said. "There are two samples taken, and one is kept in case future tests are needed. But, with a lab, there is no question of an error."
He said the next step in the process, if that sample does show drug use, is review by a medical review officer, who can determine whether the student was using a drug that has been prescribed for him, or factor in other circumstances.
Then the company contacts the parents, then the school system.
He said Sport Safe has safeguards to prevent compromise of the entire process, including the way students are chosen for testing, how the school is notified when testing will take place, and ways of avoiding substitution, in which a substance is used for a test other than the student's urine.
Some districts choose to lower the cost of testing by using their own personnel, such as a school nurse, for collection instead of having Sport Safe collectors conduct the screening.
When that is the case, the company trains the collectors.
Members of the BOE had concerns such as how to include CTE students in the pool of those screened, whether students who were 18 years old would have to have parental consent to undergo a drug screen and what process Franz recommended for those who tested positive.
Franz gave the committee a sample of a drug testing policy that has been used in a different district. He suggested the BOE consider some of the aspects of that plan when they write their own.
Dempsey said the committee is taking the information presented by Franz under consideration, and will meet again in May. She said the Board plans to have a policy in place by the beginning of the fall athletic season, in August 2013.