DYNAMIC ASSOCIATION OF RF RADIO DATA COMMUNICATION SYSTEM IN A PRE-EXISTING COMPUTER CONTROLLED NETWORK

Abstract: A Radio Data Communications System (20) capable of interfacing with an existing standard communication network (10) of linked controllers (14) and fixed terminal device (16) all operating on a pre-established protocol. The Radio Data Network (20) includes a plurality of portable radio terminals (40) each of which may emulate a fixed terminal display (16) normally operating in the existing computer controlled network. There are intended to be more portable radio terminals (40) than there are LU sessions with each of such portable radio terminals (40) being associated with a particular, defined hunt group comprised of a plurality of certain of the available LU sessions and to which the portable radio terminals (40) effectively might contend for.

Description: DYNAMIC ASSOCIATION OF RF RADIO DATA COMMUNICATION SYSTEM IN A PRE-EXISTING COMPUTER CONTROLLED NETWORK Background of the Invention This invention relates generally to RF Radio Communication Systems and, in particular, to such systems having a capability of interfacing within an existing, standardized computer controlled communication network of linked controllers and fixed terminal devices operating on a pre-established protocol. Computer control communication networks are of course known in the art. Typically, such systems utilize one or more cluster controllers interfacing with a plurality of individual terminal devices, all controlled by a host computer. One such communication network, for purposes of illustration and by way of example only, is the IBM 3270 system which is recognized as a standard in the industry. The 3270 system employs a Host Computer which includes one or more Logic Units (LU) interfacing to one or more associated 3274 Cluster Controllers, which in turn control a plurality of fixed terminal devices, such as a 3274 Display Terminal or a 3278 line Printer. The IBM 3270 system operates with a standard operating protocol, also well known in the industry. Accordingly, it will be appreciated that where an RF Radio Data Communications System is to be established, the Radio Data System may operate with some arrangement of pre-established but typically different operating protocol, which then may or may not require a separate host computer. In any event, appropriate programming must be effected to accommodate the particular operating protocol being utilized. If, on the other hand, the RF Radio Data Communication System can operate with, or at least emulate that of the pre- established computer controlled fixed communications network, say, for example, the referenced IBM 3270 system, the RF Radio Data Communications System can be made to interface with the host computer as one or more 3274 cluster controllers which in turn control a plurality of radio data portable terminals emulating either a 3278 fixed display or a 3287 line Printer. "Portable" is used to designate either a portable or mobile unit, and distinguish the same from a fixed terminal unit. In any event, the portable radio terminals may be programmed to redefine its keyboard and display output to simulate in all respects a 3278 fixed terminal device. Similarly, the portable radio terminal may connect to an optional printer device and then be programmed to simulate the IBM 3287 line printer. No reprogramming of the host computer is then necessary because all of the end terminal devices, fixed or portable, look like a 3270 device operating with standardized protocol being employed within the particular IBM 3270 computer controlled communications network. There remains still one other consideration to be taken into account. First, without more, each of the portable radio data terminals in running the 3270 emulation package, will appear to the system controller as a single fixed terminal device. As such, it occupies one of the available links to the controller in the same way as any other like fixed terminal display device. However, this could very likely necessarily prove wasteful since the radio data system portable data terminals are normally not all active, at least not all at once, but only occasionally, and on a selective basis. Moreover, if any particular link or controller fails, the portable data terminal assigned thereto would be cut off and unable to communicate with the host computer. Summary of the Invention Accordingly, it is an object of the present invention to provide an RF Radio Data Communication system that emulates a component part of a known computer-controlled communications network and operates to interface with a host computer as one or more cluster controllers and in this fashion functions to effectively overcome the foregoing deficiencies. A more particular object of the present invention is to provide and RF Radio Data Communication System of the foregoing type wherein the system portable radio data terminals emulate a known and fully compatible fixed terminal display device, but the number of such emulating portable devices may be maximized by being shared between a number of available cluster controller links. Still another object of the present invention is to provide an RF Radio Data Communication System of the foregoing type wherein the sharing of the portable Radio Data terminals is effected by the association thereof with a pool (hunt group) of selected controller link devices. In practicing the invention, an RF Radio Data Communication System is provided which is capable of interfacing as a plurality of controller links to a host computer in a computer controlled communications network of controlled terminal devices operating with a given, i.e., standardized, operating protocol. A network control processor (NCP) is interconnected to at least one of a plurality of logic units included in a host computer which supports a given number of LU sessions with each of said interconnected host computer logic units. Further, a plurality of portable radio terminals intended for operation within the RF Data Communication System are provided wherein each such terminals are adapted to emulate a compatible fixed terminal display normally operating in the controlled communication network with the standardized operating protocol. Further, the portable radio terminals are each associated with a defined hunt group comprised of a plurality of LU sessions from the given number of LU sessions available, and wherein such portable radio terminals may freely contend for an available LU session in its assigned hunt group. And finally, wherein there are a greater number of portable radio data terminals associated with the hunt group than there are LU sessions. Brief Description of the Drawings The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention itself, however, together with further objects and inventions thereof, may be best understood by reference to the accompanying drawings, in which: Fig. 1 is a block diagram of a typical computer-controlled communication network, in this case, the IBM 3270 system; Fig. 2 is a block diagram of a typical RF Radio Data Communication System controlled by an associated host computer; Fig. 3 is a block diagram of an RF Radio Data Communication System similar to that of Fig. 2, but in which the infrastructure interfaces with the host computer as a plurality of cluster controllers and in which portable radio data terminals emulate a fixed terminal device, as in accordance with the present invention; Fig. 4 is a partial block diagram showing a plurality of portable radio data terminals of the system of Fig. 3 either dynamically or statically associated with an assigned LU session; Fig. 5 is graphic representation of a series of hunt groups formed by individual portable radio data terminals associated therewith; Fig. 6 is a flow chart indicating the initialization procedure in which a given portable radio data terminal may associate with a particular LU session; Fig. 7 is flow chart of the procedure followed by the network control processor (NCP) upon receiving an inbound message from a portable radio terminal; Fig. 8 is a flow chart indicating the background actions periodically effected by the NCP regarding the dynamic association of the systems' portable radio data terminals; and Fig. 9 is a flow chart indicating the action taken by the NCP upon host link failure. Description of the preferred Embodiment Referring now to the drawings, a typical computer-controlled communication network is shown at 10 in Fig. 1. In this instance, for purposes of example only, the network is shown as an IBM 3270 System, well known in the art wherein a host computer 12 is provided which interfaces with a plurality of 3274 Cluster Controllers 14, which in turn interface with and control individual 3278 Display Terminal Devices 16. The later could be substituted with 3287 Line Printer Devices, as desired. Network 10 operates with a known, pre- established operating protocol, the details of which may not be described in detail for purposes of the present invention. Similarly, an RF Radio Communications System or network is indicated at 20 in Fig. 2, which network may likewise be considered as typical of those known in the art. As shown, system 20 includes a Network Control Processor (NCP) 22 interfacing with a Host Computer 24 and controlling in response thereto a plurality of RF Stations 26 at various locations, each of which comprise an RF Modem 28 a Transmitter 30, and a Receiver 32. Station 26 then communicates over antenna 34 with a plurality of portable radio data terminals 40. System 20 conventionally operates over inbound and outbound communications channels on a contention basis in accordance with an established operating protocol, such as that referenced in US Patent Application. Serial No. 07/175,888, filed 31 March 1988 on behalf of Kenneth J. Zdunek, et al, and assigned to the same assignee as the present invention. For purposes of brevity, such operating protocol may be referenced to as Motorola MDC 4800 operating protocol. As referenced in the 07/175,888 Zdunek Patent Application, remote data terminals transmit data messages to the Host Computer (via the NCP) in the form of data packets by RF link over the inbound channel, and receive like messages therefrom over the outbound channel. A Carrier Sense Multiple Access (CSMA) technique is utilized, which is of course well known in the art. As will be appreciated, the messages sent to the associated system remote data terminals originate at the Host Computer, and it is to the Host Computer that the remote terminals remotely communicate with in sending inbound messages. Without more, such an arrangement requires a dedicated Host Computer operating with the above-referenced protocol procedures. However, if a user already has a pre-existing Computer Controlled Network in which a Host Computer is included, and if available capacity is present, a radio data network can be added to such computer network, if, but only if, such radio data network can be made to emulate one or more cluster controllers already operating in such computer network system. For example, if the Radio Data Network 20 in Fig. 2 can be made to emulate one or more 3274 Cluster Controllers as referenced in the example of Fig. 1, the result is the overall system 100 as set forth in Fig. 3, which system has been constructed in accordance with the present invention. As therein indicated, the Radio Data System 20' is linked to the Host Computer 12 of Computer Controlled Network 10' by a plurality of direct connections 102a, 102b and 102c. In this instance, however, the RF radio data infrastructure is made to emulate a plurality of 3274 cluster controllers and in this manner, no change in the operating protocol is necessary as far as the Host Computer 12 is concerned. Each of the direct line connections 102a, 102b and 102c looks like a 3274 Cluster Controller, each of which presents a plurality of LU Sessions (typically about 32 in number). In this fashion, the full RF Radio Data System 20' may operate as usual, but in the Computer Controlled Network 10', and the Host computer 12 accommodates both system 20' as well as the various Cluster Controllers 14. However, it will be appreciated that, without more, each LU Session presented through line connections 102a, 102b and 102c would interface with an associated terminal unit (terminal session) on a one-to-one basis. Since not all of the system Radio Data Terminals are active at the same time, it would otherwise represent a less than efficient use of available resources. Moreover, if any of the LU Sessions (emulating a cluster 3274 controller) fails, the Radio Data Terminals permanently interfaced to such LU Session would thereby be cut off and denied communications access and capability. Accordingly, the present invention provides an advantageous enhancement to the aforementioned 3270 emulation protocol whereby substantially increased numbers of radio data terminals may be incorporated into the system. Also, a redundancy feature is provided to cover the drop out of any emulated 3274 Cluster Controllers and LU Session failure. And, finally, such enhancement effectively minimizes the total number of 3270 LU Sessions that may in fact be required in a particular system. To accomplish these and other objectives, each of the Radio Data Terminals 40 are selectively associated with a particular Hunt Group. Fig. 5 illustrates this feature. Conceptually, there are no limits to the number of data terminals that can in fact be associated with a Hunt Group. In practical terms, however, there are of course limits. The key criteria in this event is that all such data terminals associated with a particular Hunt Group must be of the same type. For essentially arbitrary reasons, but consistent with (IBM) protocol and architectural guidelines, type 2 is designated for conventional (3278) terminals and type 3 for (3287) printers. Similarly, each of the LU Sessions with the Host Computer (thru a link controller) are associated with a select Hunt Group. As indicated in Fig. 5, neither the group of data terminals constituting a particular terminal session, nor the LU Sessions from a particular emulated 3274 link controller, are limited to only one Hunt Group. In fact, they are to be disbursed, as indicated specifically in Fig. 5. As shown, and by way of example only, Terminals 1 through 4, of terminal session 1, are associated with Hunt Groups in this case, a type 2 LU. As will also be noted, terminal 6 of session 1, is indicated as associated with Hunt Group 2 a LU type 3 accommodating 3287 printers. Further, terminals 7 and 8 of session 1 are indicated as associated with Hunt Group 3 while terminal 9 et seq. are associated with Hunt Group N. Similarly, a portion of the available LU Sessions of 3274 Host Link 1 are associated with Hunt Group 1 while others may be associated with still different Hunt Groups, such as those shown interfacing with Hunt Group 2. Host Link 2 LU Sessions are shown selectively interfacing with Hunt Groups 2, 3 and 4. In this selective manner, it will be readily appreciated that a greater number of Data Terminals 40 can be associated with a lesser number of available LU Sessions through a particular Hunt Group. Moreover, since the LU Sessions of a particular emulated Link Controller are associated with one or more Hunt Group, a failure of that Link Controller simply means communications are rerouted through a different link Controller, thereby providing the very important redundancy feature. This is made possible by the adaptable linking of the terminals to a particular LU Session (through a particular Hunt Group). This linking may be dynamic, as through a particular Hunt Group (to any one of a number of value sessions), or static (as always associated with a specific one), as best seen in Fig. 4. As therein shown, a terminal session is considered strongly linked (dynamically) to an LU Session once such session is successfully logged on. As previously stated, a static linking always requires a particular data terminal to be associated with a predefined LU Session, as graphically portrayed in Fig. 4. Given the LU associations as described above, the flow chart represented by Fig. 6 indicates the particularized actions effected on each 3274 LU initialization request. At the start, the inquiry is made as to whether the LU is static as indicated in step 120. If yes, the LU is strongly linked to a terminal session and may proceed accordingly as indicated at step 122. If, however, the answer that the LU is not static, it by definition must be dynamic as indicated at step 124. Thereupon the further inquiry is made at step 126 as to whether the LU is weakly or strongly linked to a terminal session. If yes, the process continues with the linked terminal session at step 128 and if terminal session is logged in at step 130, a strong terminal link is effected between that terminal session and the referenced LU as indicated at 132. If the terminal session is not logged in, it simply returns to the same condition as at the beginning of the initialization process. Further, if the LU is weakly linked to a terminal session as indicated at step 126, the LU is added to the list of available LUs for the associated Hunt Group as indicated at step 134 whereupon the LU initialization process may be terminated. From the remote data terminal viewpoint, Fig. 7 represents a flow chart of the executed actions occurring upon the Network Control Processor 22 receiving inbound terminal messages. As indicated, the initial query at step 140 is as to whether the terminal session is static. If yes, the message is then forwarded to the linked LU at step 142 whereupon the process is completed at that point. If, however, the answer is that the terminal session is not static, then it must be dynamic as indicated at step 142 and the further query is made at step 144 as to whether the terminal session is weakly of strongly linked to a LU. If strongly linked, the message is forwarded to the linked LU at step 146. If the terminal session is logged in at step 148, it is strongly linked to this LU as indicated at step 150. If, however, the terminal session does not log in, it terminates and the LU initialization process will reactivate subsequently. If, on the other hand, the terminal session is weakly linked to an LU, the further query is made at step 152 as to whether the LU is available in this terminal's Hunt Group. If in the negative, an indication is returned to terminate this session because the host is not available as indicated in step 154. If on the other hand, a LU is available in the particular Hunt Group, the LU is removed at step 156 from the list of available LUs for that Hunt Group, whereupon the terminal session is weakly linked to this particular LU as indicated at step 158. The message is forwarded to the weakly linked LU at step 160 and, if the terminal session is static, the message is forwarded to the linked LU. If not, the process will terminate at this point. Fig. 8 illustrates in flow chart form the background actions executed by the network control processor 22 for dynamic LUs while Fig. 9 illustrates in flow chart form the actions executed by such network controller upon 3274 Host Link failure. In Fig. 8 the controller 22 delays for the specific delay interval as indicated at step 180 and then scans weakly linked LUs for those that have not processed traffic from their terminal session in a weak time out interval, as indicated at step 182. Accordingly, for those found, the temporary terminal session link is removed and the LU is returned to the list of available LUs for the appropriate Hunt Group as indicated in step 184. In Fig. 9 step 190 indicates that all failed 3274 LUs are removed from all associated Hunt Groups and, further, that all terminal to LU session linkages are likewise broken for the failed 3274 LUs, as shown at step 192. In this manner, the associated data terminals that would otherwise be locked out of its ability to communicate may be reassigned to viable Hunt Groups and working 3274 Link Controllers. This redundancy feature is therefore significant in insuring communication linkages with all communication capable radio data terminals. Accordingly, What is Claimed is:

Claims: _ 1. An RF Radio Data Communications System for interfacing as a plurality of controller links to a host computer in a computer controlled communications network of controlled fixed terminal display devices and which network operates with a given, standardized operating protocol, comprising in combination: a network control processor (NCP) interconnected to at least one of a plurality of logic units included in the host computer and supporting a given number of LU sessions with each of said interconnected host computer logic units; a plurality of portable radio terminals operating within the RF Radio Data System, each such terminal adapted to run an emulation program so as to simulate a fixed terminal display normally operating in the computer controlled communication network with the standardized operating protocol, each of said portable radio terminals being associated with a defined hunt group comprised of a plurality of LU sessions from said given number of LU sessions wherein said portable radio terminals may freely contend for an available LU session in its assigned hunt group, and wherein there are a greater number of portable radio data terminals associated with a hunt group than there are LU sessions; and control means for breaking the association of any failed Logic Unit with a defined Hunt Group whereby an involved portable radio terminal may seek access to the Host Computer thru any other active and functional Logic Unit still associated with that same Hunt Group. 2. An RF Radio Data Communication System in accordance with Claim 1 wherein each of said portable radio terminals is either statically or dynamically associated with its said defined Hunt Group. 3. An RF Radio Data Communication System in accordance with Claim 2 wherein said dynamically associated portable radio terminals are either strongly or weakly linked to a Logic Unit through a defined Hunt Group. 4. An RF Radio Data Communication System in accordance with Claim 3 wherein a dynamically but weakly linked portable radio terminal becomes strongly linked to a given Logic Unit through a defined Hunt Group upon LU Session log-in by that portable radio terminal. 5. An RF Radio Data Communication System in accordance with Claim 2 wherein a statically associated portable radio terminal is always strongly linked to a given logic unit through its defined Hunt Group., 6 An RF Radio Data Communication System in accordance with Claim 1 wherein each of said Hunt Groups accommodate a particular type of emulated fixed terminal device. 7 An RF Radio Data Communication System in accordance with Claim 6 wherein the types of emulated fixed terminal devices encompass at least a fixed terminal display device or a printer device. 8. An Rf Radio Data Communication System in accordance with Claim 7 wherein any such portable radio terminals previously assigned to a Hunt Group having a failed Logic Unit may be ffi disassociated therewith and reassigned to one or more different Hunt Groups. 9. In a computer controlled communications network of host computer, linked controllers and a plurality of fixed terminal devices and operating on a given, standardized operating protocol, a method of interfacing an added RF Radio Data Communications System thereto as a plurality of controller links, including the steps of: interconnecting a network control processor (NCP) to at least one of a plurality of logic units included in the host computer and supporting a given number of LU sessions with each of said interconnected host computer logic units; adapting each of the plurality of portable radio terminals operating within the RF Radio Data System to run an emulation program so as to simulate a fixed terminal device normally operating in the computer controlled communication network with the standardized operating protocol; and further associating each of said portable radio terminals with a defined hunt group comprised of a plurality of LU sessions from said given number of LU sessions wherein said portable radio terminals may freely contend for an available LU session in its assigned hunt group, and wherein there are a greater number of portable radio data terminals associated with a hunt group than there are LU sessions; and control means for breaking the association of any failed Logic Unit with a defined Hunt Group whereby an involved portable radio terminal may seek access to the Host Computer thru any other active and functional Logic Unit still associated with that same Hunt Group. 10. A method of interfacing an RF Radio Data Communications System in a computer controlled communications network in accordance with Claim 8 which includes the further step of statically or dynamically associating each of said portable radio terminals with its defined Hunt Group.

Inventors: ALONSO LEOPOLD, KORINEK FRANK W, LO BIN, STONER JOHN E, ALONSO, LEOPOLD, KORINEK, FRANK, W., LO, BIN, STONER, JOHN, E.
Applicants: MOTOROLA INC, MOTOROLA, INC.
Application year: 1991
Main classification: G06F13
IPC codes: G06F11, G06F13, H04L12, H04L29