License management system and method for commuter licensing
Contents
1. One practical application of commuter licensing accord ing to embodiments of the present invention is for networks employing laptop or notebook client computers 12 that can readily be disconnected from the network For example prior to leaving for a business trip or working at home a user can request a commuter authorization for one or more protected applications from a client computer 12 connected to the network Once a commuter authorization is granted the client computer 12 can be disconnected from the net work and can independently instantiate the protected appli cation one or more times using the commuter authorization This is in contrast to network authorizations where a client computer 12 must request and receive a network authoriza tion for each instantiation of the protected application As described earlier and illustrated in FIG 8 a developer of a software program 50 to be protected must link the software program to a corresponding shell program code or library of API functions referred to hereinafter as a client library 52 The linked software program 50 and client library 52 are then loaded onto a client computer 12 In preferred embodiments of the present invention a user can request a commuter authorization for a particular protected software program 50 by running a separate utility 54 on a client computer 12 networked to the server pool In preferred embodiments this utility 54 enables the user to specify the licens2. system as recited in claim 4 the requesting client computer being programmed for returning the commuter authorization by setting its check in value to a returned state and communicating a check in message to the granting license server and the granting license server being further programmed for setting its check in value to the returned state and incrementing its count of available allocations upon receipt of the check in message 6 Asystem as recited in claim 5 wherein if the commuter authorization is not returned prior to an expiration of the commuter authorization lifetime at the expiration of the commuter authorization lifetime the requesting client computer is further programmed for setting its check in value to a returned state and the granting license server is further programmed for setting its check in value to the returned state and incrementing its count of available allocations 7 A system as recited in claim 4 the at least one license server comprising a pool of license servers and wherein the granting license server is further programmed for communicating the commuter authorization life time and the check in value stored in the granting license server to other license servers in the pool when the granting license server grants the commuter autho rization to the requesting client computer so that even if the granting license server should go down another license server in the pool can act as the granting licens
3. among one or more users on the network Protected software may include but is not limited to for example a software program such as a Word processing program a graphics program a computer game etc a proprietary file or other data structure such as a data base or other form of data as well as other software encoded information or instructions for which the control of user access is desired For purposes of simplifying the present disclosure the protected software used in the fol lowing examples is one or more proprietary software pro grams According to a preferred embodiment of the present invention the plurality of license servers are managed in accordance with a server pool scheme as controlled by a license management program associated with each license server computer and the shell program or library of API functions associated with each copy of the protected soft ware program In preferred embodiments the pool of license servers comprises three to 11 servers However it should be noted that alternative embodiments of the present invention are not limited to any particular maximum number of license servers In addition in further alternative embodiments multiple pools of license servers can reside on a single network In further alternative embodiments only a single license server is required for issuing commuter authoriza tions However for purposes of illustration only embodi ments of the present invention will be d
4. 1997 elan 002603 002609 pp i vi Common Licensing API License Service Application Programming Interface API Specification v1 02 Jan 28 1993 RTI 3389 3413 pp i 22 Auto Trol Technology Corp Auto Trol Software Protec tion Installation Guide Apr 4 1986 FF00016 00025 10 pages Elan Computer Group Elan License Manager Technical Overview Nov 13 1997 ELAN 001702 001757 pp 1 9 1 2 i iii 1 44 Highland Software Inc FLEXIm End User Programmers Manual Mar 8 1991 BP 00022 BP 00037 pp 1 3 9 11 19 21 A1 A3 45 61 62 84 85 Auto Trol Technology Corp FLEXIm Programmers Guide Dec 1994 BP 00098 000137 pp 1 36 1 4 Highland Software Inc FLEXIm License Manager Technical Overview Oct 1991 8 pages Globetrotter Software Inc FLEXIm Programmers Guide for Windows Version 5 11 Mar 1997 RTI 5219 5290 pp i 65 Globetrotter Software Inc FLEXIm End User Manual Version 6 0 Oct 1997 RTI5129 5217 pp 1 80 Globetrotter Software Inc FLEXIm Refernce Manual Ver sion 6 0 Dec 1997 RTI5291 5508 pp i 206 Globetrotter Software Inc FLEXIm Reference Manual Version 6 1 Jan 21 1999 RTI5509 5942 PCT International Search Report as issued in International Application No PCT US00 24359 Mailing Date Aug 2 2001 cited by examiner U S Patent Nov 22 2005 Sheet 1 of 4 US 6 968 384 B1 LIC SERVER A LIC SERVER B LIC SERVER C b RL
5. 4 only 99 of the 100 allocations have been initially assigned by the network administrator If the network administrator makes an initial distribution that does not equal the hard limit of allocations see reference character 28 in preferred embodiments of the present invention the extra allocations will be put into a free pool 48 maintained within the distribution table 36 Thus in the example of FIG 4 one allocation is put into free pool 48 If on the other hand the network administrator makes no initial distribution 30 of allocations in the RLF 24 preferred embodiments will divide the allocations evenly over the number of servers in the pool and any extras will be put in the free pool 48 For example but not illustrated in FIG 4 if no initial distri bution 30 was assigned by the network administrator infor mation representing an even distribution of A 33 B 33 and C 33 would be stored in the initial distribution attribute 30 of the RLF 24 and when a particular license server 14 is started the RLF 24 would load an even distribution of A 33 B 33 and C 33 into the current distribution attribute 40 of distribution table 36 and would load a value of one into the free pool 48 In preferred embodiments of the present invention when the license servers 14 in the server pool are started up one of the license servers is designated as a leader server Selection of a leader server is described in a related U S utility application e
6. granted Such a system provides a degree of protection against system failure in the event that one of the license servers crashes or goes down The down server computer would not respond to the poll but other server computers having appropriate license information in their license file would respond to the poll thus allowing the client computer to continue to seek authorization to run the protected software program even though one of the servers was down While the above SENTINELLM systems have operated well in many contexts each license server operates some what independent of other license servers Accordingly there is a need in the industry for improvements in connec tion with management and coordination of multiple license servers or a pool of license servers in software license management systems for computer networks SUMMARY OF THE DISCLOSURB Therefore it is an advantage of embodiments of the present invention to provide a license management system and method for more efficiently managing licenses on a network using a pool of multiple license servers It is a further advantage of embodiments of the present invention to provide a system and method for managing licenses on a network that allows a client computer to request and receive a commuter authorization from a license server while connected to the network allowing the client computer to run a protected software program even if the client computer should become disc
7. preferred embodiments of the present invention the leader server always has a global picture of the distribution of allocations in the whole server pool Thus in the present example any changes to the distribution table of follower server B must be communicated to leader server A In preferred embodiments follower server B can determine the IP address for the leader server A from a leader priority list 46 which is configurable by the network administrator It should be noted that in preferred embodiments the IP address of all license servers 14 in the server pool are stored in the leader priority list 46 a data structure separate from the license codes 26 to facilitate faster lookup However in alternative embodiments the IP addresses may be stored in a record associated with the license codes 26 In any case after determining the IP address of the leader server A follower server B communicates the fact that its available allocations count has dropped to 29 to leader server A and the distribution table of leader server A will be updated accordingly Thus as illustrated in FIG 6 the distribution table 36 of leader server A reflects that the available allo cations record 38 for follower server B has dropped to 29 the allocations in use record 42 for follower server B has increased to 1 and that the record for allocations available for all servers in the pool see reference character 44 has dropped to 99 The preceding discussion descr
8. program into the transient memory of the client computer 12 along with the program code corresponding to a shell or library of API functions Alternatively the protected program may remain in persis tent memory 18 until and unless the server computer com municates an authorization signal to the shell program or library of API functions Selection of a follower server from which to request authorization is described in a related U S utility application entitled System and Method for Select ing a Server in a Multiple Server License Management System Ser No 09 648 853 filed Aug 25 2000 the contents of which are incorporated by reference herein Alternatively the protected program may remain in persis tent memory 18 until and unless the server computer com municates an authorization signal to the shell program or library of API functions Loading of the shell program or library of API functions is preferably transparent to the user on the client computer 12 and preferably occurs in response to the user inputting a command to open the protected software for example by clicking a mouse button on an icon associated with the protected software As part of the function of the shell or library of API functions a request is then sent from the client computer 12 to follower server B for one or more authorizations to run the protected program For purposes of this example assume that client computer 12 requested only one authorization
9. 38 for follower server C decreases to 29 and the allocations in use record 42 for follower server C increases to one In so doing one of the available allocations for a network autho rization has been effectively transformed into a commuter authorization It should be noted that in preferred embodiments of the present invention follower server C may receive multiple requests for commuter authorizations from client computers 12 and may grant as many commuter authorizations as there are available allocations However if an insufficient number of allocations are available in preferred embodiments fol lower server C may then issue a borrow request in an attempt to borrow an available allocation from another license server 14 In alternative embodiments the network administrator or software developer may limit the number of commuter authorizations that may be issued as a percentage of the hard limit of allocations stored in the hard limit record 28 for a particular protected software program 50 When a commuter authorization is sent to the client computer 12 additional commuter authorization informa tion is also encrypted and sent to the client computer 12 As illustrated in FIG 8 this commuter authorization informa tion includes fingerprint information 60 which uniquely identifies the client computer 12 authorized to receive the commuter authorization and a commuter authorization life time 56 which in preferred embodiments of the prese
10. F RLF RLF Mc 22 LMPROGRAM LM PROGRAM LMPROGRAM 22 100 7 12 CLIENT 1 CLIENTN 12 PROGRAM PROGRAM 24 REDUNDANT LICENSE FILE 9g LICENSE CODE 257 LICENSE CODE B 0 7 LICENSE CODE C FIG 2 UcENSECODE 5 7 R3 RN FIG 3 U S Patent Nov 22 2005 39 APPL V1 0 100 8 30 C 30 A33 A PADDR APPL V1 0 B 30 B IP ADDR C 30 C IP ADDR LICENSE TABLE 34 FIG 4 Sheet 2 of 4 US 6 968 384 B1 A IP ADDR B IP ADDR C IP ADDR FREE POOL FP 1 DISTRIBUTION TABLE 36 48 U S Patent LIC SERVER A Nov 22 2005 Sheet 3 of 4 US 6 968 384 LIC SERVERB LIC SERVERC APPL 400 X 39 X X V1 0 B 3 X X C 30 0 30 A IP ADDR A IP ADDR IP ADD B IP ADD C IP ADD C IP ADDR A IP ADDR B IP ADD C IP ADD APPL 100 v1 0 2 28 M 40 42 3 LIC SERVER A FIG 5 LIC SERVER C A IP ADDR A IP ADDR B IP ADD B IP ADD C IP ADD C IP ADDR A IP ADDR B IP ADD C IP ADD FIG 6 LIC SERVER B LIC SERVERC APPL 100 3910 39 100 V1 0 B 30 1 29 V1 0 3011 29 26 28 A IP ADDR A IP ADDR A IP ADDR B IP ADD B IP ADD B IP ADD C IP ADDR C IP ADDR C IP ADDR U S Patent Nov 22 2005 Sheet 4 of 4 US 6 968 384 B1 LIC SEVER 14 RF mY 4 UTILITY RLF D m3 m 12 CLIENT 56 58 60 UTILITY FIG 8 US 6 968 384 B1 1 LICENSE MANAGEMEN
11. Follower server B under the control of the license manage ment software responds to the request by looking at its distribution table 36 to determine whether it has available allocations for Application v1 0 In the example of FIG 5 follower server B has 30 allocations available as repre sented by the available allocations record for each server in US 6 968 384 B1 9 the pool reference character 38 in the distribution table 36 for follower server B Because it has available allocations follower server B communicates an authorization message to the client computer 12 As illustrated in FIG 6 once the authorization message is sent the distribution table 36 is updated so that the available allocations record 38 for follower server B decreases to 29 and the allocations in use record 42 for follower server B increases to one If an insufficient number of allocations are available to com pletely satisfy the request no authorizations are sent and follower server B communicates another message back to the client computer 12 denying the request In preferred embodiments follower server B will then issue a borrow request in an attempt to borrow available allocations from another source Borrowing is described in a related U S utility application entitled License Management System and Method with License Balancing Ser No 09 648 720 filed Aug 25 2000 the contents of which are incorporated by reference herein As noted above in
12. Proceedings Nov 1984 pp 171 172 InfoWorld FST Introduces a Copy Protection Scheme For Nets vol 7 No 7 Nov 25 1985 p 14 Micro Communications Software Protection vol 2 No 5 May 1985 pp 35 37 PC World LAN Licensing Lags vol 3 No 11 Nov 1985 pp 320 324 328 Rifkin A et al RFS Structural Overview USENIX Summer Conference Proceedings Atlanta Ga Jun 9 13 1986 pp 248 259 Gould E The Network File System Implemented on 4 3BSD USENIX Conference Atlanta Ga Jun 9 13 1986 pp 294 298 Software News The Promise of LANS MIS Back in Control pp 51 54 56 58 IBM Technical Disclosure Bulletin Device Profile Instal lation Procedure with Validation vol 28 No 4 Sep 1985 p 1487 The DEC Professional PACS Plus Relief for VAX VMS Resource Management Headaches Feb 1986 pp 58 62 64 Software News LAN Applications Prices Are Not Easy to Set Apr 1987 pp 54 56 58 SIGUCCS Newsletter Licensing of Microcomputer Software vol 15 No 4 Winter 1985 pp 9 12 AMC SIGUCCS User Services Conference IX A Software Management System Atlanta Ga Oct 11 14 1981 pp 9 17 Brooks C Experiences with Electronic Software Distribu tion USENIX Summer Conference Portland Oregon Jun 11 14 1985 pp 433 436 Leiss E On Authorization Systems with Grantor Controlled Propagation of Privileges CompCon 83 San F
13. T SYSTEM AND METHOD FOR COMMUTER LICENSING CROSS REFERENCE TO RELATED APPLICATIONS Embodiments of the present invention claim priority from Provisional Application Ser No 60 152 785 filed Sep 7 1999 and are related to U S utility patent applications entitled License Management System And Method With Multiple License Servers Ser No 09 648 697 filed Aug 25 2000 License Management System And Method With License Balancing Ser No 09 648 720 filed Aug 25 2000 and System And Method For Selecting A Server In A Multiple Server License Management System Ser No 09 648 853 filed Aug 25 2000 The contents of each of these applications are incorporated by reference herein BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates generally to license man agement systems and processes for managing licenses on a computer network and in preferred embodiments to such systems and processes involving a pool of license servers for managing software licenses among one or more users on the network and for granting authorizations to use protected software programs to client computers that may become temporarily disconnected from the network 2 Description of Related Art The increasing popularity of computer usage in homes and businesses as well as in governmental research and education institutions has brought about a world wide demand for greater software variety and sophistication Indee
14. United States Patent US006968384B1 12 10 Patent No US 6 968 384 B1 Redding et al 45 Date of Patent Nov 22 2005 54 LICENSE MANAGEMENT SYSTEM AND 5 146 575 A 9 1992 Nolan Jr METHOD FOR COMMUTER LICENSING 5 390 297 A 2 1995 Barber et al 5 745 879 A 4 1998 Wyman 75 Inventors Mark E Redding Newport Beach CA 5 790 664 A 8 1998 Coley 709 203 US Logan A Badia Fullerton CA 5 862 348 A 1 1999 Pedersen US Sandeep Handa New Delhi IN Hemant Sharma Lake Forest Continued CA US Sanjay Chopra New Delhi TAN UN Gupta Haryana IN FOREIGN PATENT DOCUMENTS Poonam Lal Haryana IN GB 2316503 8 1996 73 Assignee Safenet Inc Belcamp MD US OTHER PUBLICATIONS 5 PC Week Strength in Numbers vol V3 Jul 1986 p 57 Notice Subject to any disclaimer the term of this patent is extended or adjusted under 35 Continued U S C 154 b by 794 days Primary Examiner Paul H Kang 21 Appl No 09 648 502 74 Attorney Agent or Firm Venable LLP 22 Filed Aug 25 2000 57 ABSTRACT Related U S Application Data 60 Provisional application No 60 152 785 filed on Sep A system for managing licenses for protected software on a 7 1999 communication network is disclosed The system includes at least one client computer that is capable of being coupled to 51 Int ens G06F 15 16 GOGF 15 173 or decoupled from the communication network While HO4L 9 00 coupl
15. communicate the fact that its available allocations count has dropped to 29 to leader server A and the distribution table of leader server A will be updated accordingly Thus as illustrated in FIG 7 the distribution table 36 of leader server A reflects that the 10 15 20 25 30 35 40 45 50 55 60 65 12 available allocations record 38 for follower server C has dropped to 29 the allocations in use record 42 for follower server C has increased to 1 and that the record for alloca tions available for all servers in the pool see reference character 44 has dropped to 98 Until the commuter autho rization is returned or otherwise canceled the hard limit of available allocations in the server pool is effectively decre mented by one In addition in alternative embodiments the commuter authorization lifetime and the check in value are communi cated from follower server C to the other license servers 14 in the server pool and stored in memory so that even if follower server C should go down the other license servers 14 in the server pool can take over the management of the issued commuter authorization Referring again to FIG 8 once the commuter authoriza tion is sent by the license server 14 it is received by the client library 52 that initiated the commuter authorization request Once received the client computer 12 can be disconnected from the network because the commuter authorization information r
16. d the software development industry in most indus trialized countries has shown substantial growth in recent years and is expected to show continued growth through the next decade However as software sophistication increases develop ment costs associated with such software also tend to increase Modern software programs can require months or even years of development often involving expensive resources and teams of highly skilled engineers and pro grammers before a product may be readied for sale or license Thus software development companies are often required to make large investments early in the development of their products in the hope that the products will provide a volume of sales or license revenues sufficient to cover their development investments and generate profits Illegal software usage and piracy have become a signifi cant problem to software development companies Because of the nature of computer software illegal usage and illegal copying of proprietary software programs can be difficult to detect or deter The increasing usage of computer networks has added to the problem Computer networks can allow multiple users to access and copy software stored by a common network program server or copy and pass software between each other over the network A legitimately pur chased or licensed copy of a software program available on network could result in many illegitimate usages or copies by unauthorized or unlicensed u
17. e server 8 A system as recited in claim 1 the requesting client computer being programmed for enabling a user to select the commuter authorization lifetime 9 A system as recited in claim 1 the requesting client computer being programmed for enabling a user to select the license server from which to request a commuter authori zation 10 A method for managing licenses for protected soft ware on a communication network the method comprising the steps of coupling at least one client computer and at least one license server to the communication network configuring the at least one client computer with the protected software the protected software being inde pendent of the at least one license server communicating a request for a commuter authorization to use the protected software from the at least one client computer to the at least one license server over the communication network granting a commuter authorization to the at least one client computer from the at least one license server and decrementing a count of available allocations within the at least one license server only if there is an available allocation in the at least one license server storing a commuter authorization lifetime representing a time period for which the commuter authorization is valid within the at least one client computer wherein after a commuter authorization is communicated from a granting license server to a requesting client com puter the requ
18. e computer in which the special hardware device is installed Accordingly more sophisticated license management software has been developed for managing software licenses for computer networks which do not require encryption of the protected software or special hardware devices in each authorized user s computer For example the assignee of the present invention Rainbow Technologies Inc has mar keted versions of a license management system under the trademark SENTINELLM The SENTINELLM sys tems operate with a license server connected to a network of users The license server stores and manages software licenses for the network users in accordance with a license management program stored on the server Each copy of a protected software program on the network is accompanied by a program code corresponding to a shell also known as wrapper or library of Application Program Interface API functions which communicates with the license man agement program on the server When a user starts to run the protected software program the shell code or library of API functions provided with the program communicates a request to use a license to the license server over the network The server under the control of the license man agement software responds to the request to determine whether it is storing an available license for the protected software program If so the server communicates an autho rization message to the user and decre
19. e server 14 from which the commuter authorization will be requested and the requested time duration of the commuter authorization The utility 54 invokes the client library 52 associated with the requested software program 50 which first makes a local check to determine if the client library 52 has already received a commuter authorization If it has the utility 54 terminates If it has not then the client library 52 sends a request for a commuter authorization to the specified license server 14 in the server pool The request includes a fingerprint information that uniquely identifies the client computer 12 from which the request is made In alternative embodiments of the present invention a user can also request a commuter authorization for a par ticular protected software program 50 by attempting to open the protected software program 50 In preferred embodi ments the client library 52 associated with the requested software program 50 first makes a local check to determine if the client library 52 has already received a commuter authorization If it has the protected software program 50 is opened as will be described in greater detail below If it has not then the client library 52 sends a request for a commuter authorization to the specified license server 14 in the server pool and once a commuter authorization is received the protected software program 50 is opened In alternative embodiments the client library 52 does not ma
20. eceived by the client library 52 allows it to independently perform a function similar to a license server 14 Upon receiving a subsequent or present request to run the protected software program 50 the client library 52 decides if it can authorize the client computer 12 to run the requested program 50 by decoding the commuter authorization information and comparing the fingerprint 60 commuter authorization lifetime 56 check in value 58 and other information to parameters within the client computer 12 If authorization is permitted then an instantiation of the protected software program 50 is opened With a commuter authorization the client library 52 can open the protected software program 50 multiple times including multiple simultaneous instantiations It should be noted that once a commuter authorization has been received by the client library 52 all subsequent requests to open the protected software program 50 will be managed by the client library 52 without resorting to a networked license server 14 even though the client computer 12 may still be connected to the network at that time The communication or pinging that occurs between a client computer 12 that has received a network authorization from a license server 14 is described in a related U S utility application entitled License Management System and Method with Multiple License Servers Ser No 09 648 697 filed Aug 25 2000 the contents of which are incor porated b
21. ecution of the license management software running on a single license server 14 Thus any given licenser server 14 does not need to have multiple license management processes running to manage licenses for multiple protected vendor applications Instead only one license management program needs to be running on a given license server 14 to manage licenses for protected vendor applications managed by that license server In the example embodiment of FIG 3 a license code 26 comprises a data string defining multiple records or fields R1 R2 RN wherein each record corresponds to an attribute associated with the license policy the software program to which the license policy applies or other infor mation In preferred embodiments each license code 26 includes at least one attribute associated with a license policy the number of allocations for using the protected software program and at least one other attribute associated with the identity of the protected software program The number of allocations for using the protected software program is the maximum number of users that can be running the protected software program at any one time and is also referred to as the ceiling or hard limit In preferred embodiments license code 26 also includes a flag which determines if commuter licensing functionality described herein is enabled or disabled for the corresponding pro tected software program This flag allows the software dev
22. ed to the communication network a user of the client 52 U S Cl 709 229 709 225 713 201 computer may request a commuter authorization to use the 705 52 705 59 protected software At least one license server is also 58 Field of Search 709 201 202 coupled to the communication network Each license server 709 203 217 226 229 713 153 160 170 is programmed for managing a distribution of allocations to 713 173 185 201 705 52 59 use the protected software In addition at least one of the license servers is programmed for granting a commuter 56 References Cited authorization in response to a request for a commuter authorization from a client computer if there is an available U S PATENT DOCUMENTS authorization After a commuter authorization is received by 4 652 990 A 3 1987 Pailen et al a client computer the client computer stores a commuter 4 658 003 A 4 1987 Hellman authorization lifetime representing a time period for which 4 685 055 A 8 1987 Thomas the commuter authorization is valid The client computer 4 754 395 A 6 1988 Weisshaar et al may then use the protected software while coupled to or 4 780 821 A 10 1988 Crossley decoupled from the communication network until the com 4 791 565 A 12 1988 Dunham et al muter authorization lifetime expires 4 796 220 A 1 1989 Wolfe 5 117 222 5 1992 McCurdy et al 340 573 4 5 138 712 A 8 1992 Corbin 17 Claims 4 Drawing Sh
23. eets 14 14 LIC SERVER A RLF LIC SERVER B RLF LIC SERVER RLF US 6 968 384 B1 Page 2 U S PATENT DOCUMENTS 5 970 143 A 10 1999 Schneier et al 713 81 6 101 606 A 8 2000 Diersch et al 713 201 2002 0161718 A1 10 2002 Coley et al 705 59 OTHER PUBLICATIONS Digital Review Apollo Licenses Concurrent Users on Entire Network vol 4 No 20 Oct 26 1987 p 6 IBM Technical Disclosure Bulletin Software Serial Number vol 26 No 7B Dec 1983 pp 3918 3919 Chovan J Handling Site License Agreements and Public Domain Software Packages What are the Issues ACM SIGUCCS Conference Toledo Ohio Sep 30 Oct 4 1985 pp 175 179 Brown B Microcomputer Software Exchange at Michigan State University ACM SIGUCCS Conference Toledo Ohio Sep 30 Oct 4 1985 pp 185 197 Halaris A Sloan L Networked Microcomputers New Challenges For Computing Center Management SIGUCCS Newsletter vol 13 No 4 Winter 1983 pp 20 26 Gerber H Pringle G Instructional Computing and Local Area Networking SIGUCCS Newsletter vol 17 No 2 Summer 1987 pp 8 13 Kreutzer A An On Line System For Controlling and Monitoring Software Usage in a Microcomputer Labora tory SIGUCCS Newsletter vol 18 No 2 Summer 1988 pp 29 32 Allen K Software Lending Library ACM SIGUCCS XII Conference
24. eloper to make commuter licensing available only to selected customers Data associated with a license policy preferably includes data representing the expiration date or expiration time of the license as granted by the licensee e g the protected software program s owner or developer For purposes of illustration only in the example of FIG 4 only one fictional license code 26 identified as Appli cation v1 0 is stored in the RLF 24 of a license server 14 with a hard limit of 100 total allocations distributable across all license servers 14 see reference character 28 In pre ferred embodiments another attribute of the RLF 24 is the IP address 32 for each license server 26 Another attribute of the RLF 24 is the distribution of the 100 allocations across all the license servers 14 This distribution is identified as the initial distribution 30 and is configurable by the network administrator In the example of FIG 4 an initial distribu tion 30 of A 39 B 30 C 30 indicates that 39 allocations will initially be assigned to license server A 30 allocations will initially be assigned to license server B 30 allocations will initially be assigned to license server C and one allocation will initially be assigned to the free pool 48 This initial distribution 30 also signifies that the pool will comprise three license servers US 6 968 384 B1 7 In preferred embodiments of the present invention each RLF 24 stored in each lic
25. en effectively transformed into a commuter authorization The network administrator is then provided encrypted commuter authorization information as described above This encrypted commuter authorization information is conveyed to the user of the remote client computer 12 through non networked communications such as by tele phone e mail or the like The user then enters this infor mation into the utility which decodes and provides this information to the client library 52 linked to the requested software program 50 At this point the commuter authori zation has been received and thereafter both the client 10 15 30 45 50 55 60 65 14 computer 12 and the server pool manage the commuter authorization in the usual manner as described above Therefore embodiments of the present invention provide an improved license management system and method for more efficiently managing licenses on a network using a pool of multiple license servers Embodiments of the present invention provide a system and method for managing licenses on a network that allows a client computer to request and receive a commuter authorization from a license server while connected to the network which allows the client computer to run a protected software program even if the client computer should become disconnected from the network In addition embodiments of the present invention provide a system and method for managing licenses on a network tha
26. ense server 14 is an exact copy of every other RLF 24 of license servers in the pool Thus attributes of the license code 26 such as the expiration date or number of allocations need not be passed between license servers 14 in response to a request for authorization to used protected software program from a client computer 12 because an exact copy of the license code 26 has already been stored on the hard disk of each license server 14 prior to the startup of that license server 14 Each license server 14 operates under the control of its associated license management program 22 to perform license management functions in association with data con tained in the RLF 24 as described herein Thus when a particular license server 14 is started the license server 14 loads the contents of its RLF 24 into a license table 34 in RAM or other memory and reads the license table 34 which identifies that server as a license server 14 It should be noted that in preferred embodiments the license table 34 is never modified In addition the contents of the RLF 24 is loaded into a distribution table 36 in RAM or other memory and the initial distribution 30 is further copied into another record distinct from the license code 26 identified as a current distribution 40 Unlike the license table 34 the distribution table 36 changes its current distribution 40 over time to keep track of current allocations It should be noted that in the example of FIG
27. escribed herein with reference to a pool of three license servers An example hardware environment for an embodiment of the present invention is illustrated generally in FIG 1 With reference to FIG 1 a computer network 10 includes a plurality of user or client computers 12 and three license servers 14 each coupled for communication over a com munication network link generally referenced at 16 The plurality of client computers 12 are identified as Client 1 Client 2 and Client N and the plurality of license servers 14 are labeled as Lic Server A Lic Server B and Lic Server C Embodiments may employ any suitable number of client computers 12 and any suitable number of license servers 14 Also while not shown in FIG 1 the network 10 may include additional components including one or more program or file servers routers and or other well known network devices and resources Each client computer 12 preferably includes a suitable processor and associated transient memory such as a RAM for running a protected software program The client com puter may be part of a standard personal computer PC network terminal workstation or the like In one preferred embodiment each client computer 12 is coupled to a per sistent program storage memory device 18 which may include but is not limited to a hard disc drive floppy disc drive tape drive CD ROM or the like having a computer readable medium on wh
28. esting client computer may use the protected software while coupled to or decoupled from the communication network until the commuter autho 10 15 30 35 40 45 50 55 65 16 rization lifetime expires the requesting client computer utilizing the commuter authorization independently of the at least one license server and detecting attempts to tamper with an internal clock of the requesting client computer and invalidating the com muter authorization if tampering is detected 11 A method as recited in claim 10 wherein while the requesting client computer maintains a valid commuter authorization the requesting client computer is capable of opening the protected software multiple times including simultaneous instantiations of the protected software 12 A method as recited in claim 10 the step of granting a commuter authorization to the at least one client computer from the at least one license server further including the steps of communicating the commuter authorization lifetime and a check in value from the granting license server to the requesting client computer and storing the commuter authorization lifetime and the check in value in the requesting client computer and the granting license server 13 Amethod as recited in claim 12 wherein the protected software is no longer needed the method further includes the steps of returning the commuter authorization by setting the check in value stored i
29. ibed a client computer 12 requesting and receiving authorization for running a pro tected software program from a networked license server 14 In the operating environment described above the client computer 12 must remain connected to the network to continue to run the protected software program For pur poses of distinguishing the above described system from embodiments of the present invention the authorizations described in the preceding discussion will be referred to hereinafter as network authorizations Commuter licensing will be described next according to embodiments of the present invention Commuter licensing departs from the concept of requesting and granting a network authorization between license server 14 and client computer 12 and instead is concerned with requesting and granting a commuter authorization between license server 14 and client computer 12 While a network authorization is managed by the issuing license server 14 and the server pool commuter authorizations once granted to a particular client computer 12 are managed both by the client computer 12 and also by the issuing license server 14 It should be noted however that although embodiments of the present invention described herein include a pool or license servers 10 15 20 25 30 35 40 45 50 55 60 65 10 14 in alternative embodiments only a single license server 14 is required for issuing commuter authorizations
30. icense code 26 is a record for available alloca tions for each server in the pool see reference character 38 a record for available allocations for all servers in the pool see reference character 44 and a record for allocations currently in use for each server in the pool see reference character 42 The allocations in these records are values which are incremented or decremented as authorizations are issued returned or borrowed It should be understood that the records identified by reference characters 28 38 40 42 and 44 in FIG 5 are associated with a particular license code 26 but are distinct from it As indicated in FIG 5 in preferred embodiments of the present invention the structure of the distribution tables 36 will be the same for both the leader server A and follower servers B and C but only the distribution table 36 for leader server A the leader distribution table will reflect the allocation status of the other license servers 14 in the server pool In contrast the distribution tables 36 for follower servers B and C the follower distribution tables will only reflect the allocation status of that particular follower server as indicated by the X don t care designations in portions of the follower distribution tables When a user at a client computer 12 desires to run Application v1 0 from a follower server such as follower server B for example the client computer 12 may first load some or all of the protected
31. ich the protected software program is stored Also stored as part of the protected software program is additional program code such as code corre sponding to a shell or library of API functions as discussed above for communicating with the server computers which are under control of a license management program in accordance with communication functions discussed below Each license server 14 preferably includes a suitable processor and associated transient memory such as an 10 15 20 25 30 35 40 45 50 55 60 65 6 RAM for running a license management program as described herein In addition each license server 14 is coupled to one or more persistent program storage memory devices 20 which may include but is not limited to a hard disc drive floppy disc drive tape drive CD ROM or the like having a computer readable medium on which a license management program 22 and a redundant license file RLF 24 are stored An example embodiment of an RLF 24 is shown in FIG 2 as containing license codes 26 for proprietary software programs A B C etc Each license code 26 in one example embodiment comprises a string of data relating to license policy and the software program to which the license policy applies In preferred embodiments license codes 26 for software produced by more than one vendor may reside within the same RLF 24 of the same license server 14 and may be managed with a single process ex
32. ke a local check but immediately sends a request for a commuter authorization to the specified license server 14 in the server pool In preferred embodiments of the present invention com muter authorizations and network authorizations can be simultaneously received and managed Thus a commuter authorization can be requested and received by a client computer 12 even though the client computer 12 may already have a network authorization for the same protected software program 50 When a license server 14 receives a request for a com muter authorization the license server 14 under the control of the license management software 22 responds to the request by looking at its distribution table 36 to determine whether it has an available allocation for Application v1 0 US 6 968 384 B1 11 Continuing the example of FIG 6 for purposes of illustration only assume that a request for a commuter authorization has been made to follower server C In the example of FIG 6 follower server C has 30 allocations available as repre sented by the available allocations record for each server in the pool reference character 38 in the distribution table 36 for follower server C Because it has an available allocation follower server C sends a commuter authorization message to the client computer 12 As illustrated in FIG 7 once the commuter authorization message is sent the distribution table 36 is updated so that the available allocations record
33. license server in the pool and check in will be managed by that license server In alternative embodiments however rather than checking in the commuter authoriza tion the commuter authorization is held by the client library 52 for the full term of the commuter authorization lifetime It is also possible that the client computer 12 may not be re connected to the network and may not return the com muter authorization to the issuing license server 14 within the commuter authorization lifetime As noted above the commuter authorization lifetime and the check in value 58 are stored in persistent memory in both the license server 14 and the client computer 12 Thus if the commuter authori zation lifetime ends prior to the return of the commuter authorization the check in value 58 within the client library 52 and license server 14 is automatically set to indicate that the commuter authorization has been checked in Thereafter the commuter authorization is disabled Within the license server 14 the number of available allocations is incremented by one and this change communicated to the leader server If the granting license server is down and the commuter authorization lifetime ends prior to the return of the com muter authorization another license server will manage the automatic check in of the commuter authorization Situations may occur where a user operating a client computer 12 remote from the network may need to obtain a commuter au
34. ments a count of available licenses stored by the server If not the server communicates another message to the user indicating that no licenses are available In this manner licenses are always stored and managed on a network license server Each network user may have a copy of a protected software program but must communicate with the license server for authorization to use the protected program License management systems which employ a license server as discussed above provide significant advantages with respect to the freedom to readily add delete or change authorized users on the network and the ability to readily control and alter licensing schemes for example to add or delete licenses or change conditions for licenses by modi fying only the license server files or programs However if all licenses are stored and managed in a single license server failure of that server can result in a failure of the entire license management system Accordingly prior versions of the SENTINELLM systems include multiple license server capabilities wherein two or more license servers are provided on the network each having a pre loaded license file and a license management program One of the servers US 6 968 384 B1 3 may be designated as a primary license server while the others are designated as backup servers If the primary server cannot be reached by a user for example because the primary server has crashed or otherwise gone d
35. n the requesting client computer to a returned state and communicating a check in message to the granting license server and setting the check in value stored in the granting license server to the returned state and incrementing the count of available allocations stored in the granting license server when the granting license server received the check in message 14 A method as recited in claim 12 wherein if the commuter authorization is not returned prior to an expiration of the commuter authorization lifetime at the expiration of the commuter authorization lifetime the method further includes the steps of setting the check in value stored in the requesting client computer to a returned state and setting the check in value stored in the granting license server to the returned state and incrementing the count of available allocations stored in the granting license server 15 A method as recited in claim 12 the at least once license server comprising a pool of license servers the method further including the steps of communicating the commuter authorization lifetime and the check in value stored in the granting license server to other license servers in the pool when the granting license server grants the commuter authorization to the requesting client computer so that even if the granting license server goes down another license server in the pool acts as the granting license server 16 A method as recited in claim 10 the
36. nt invention is set to 30 days from the granting of the commuter authorization In alternative embodiments however the commuter authorization lifetime 56 can be set by the system administrator to any value less than the remaining time of the license as limited by the overall expiration date of the license The commuter authorization information also includes a check in value 58 which indicates whether the commuter authorization has been returned to the server pool The commuter authorization lifetime 56 and the check in value 58 are stored in persistent memory in both the issuing license server 14 and the client computer 12 Other commuter authorization information may include but is not limited to the feature name and version which identifies the protected software program for which a com muter authorization is granted and a clock tampering value which when enabled allows the client library to detect attempts to tamper with the client computer s clock and invalidate commuter authorization if tampering is detected In preferred embodiments of the present invention the clock tampering value is enabled As noted above in preferred embodiments of the present invention the leader server always has a global picture of the distribution of allocations in the whole server pool Thus in the present example any changes to the distribution table of follower server C must be communicated to leader server Follower server C will therefore
37. ntitled System and Method for Select ing a Server in a Multiple Server License Management System Ser No 09 648 853 filed Aug 25 2000 the contents of which are incorporated by reference herein Other license servers 14 are designated as follower servers The leader server always maintains a global picture of the current distribution of allocations within every license server 14 the server pool For purposes of illustration only FIG 5 illustrates an example of the distribution tables 36 for a three server pool consisting of license servers A B and C Assume for this illustration that all three license servers have been started up and that license server A has been designated as the leader server and B and C as the follower servers Further assume that the hard limit of allocations for the software 10 15 20 25 30 35 40 45 50 55 60 65 8 program Application v1 0 is 100 as indicated by the hard limit record 28 associated with the license code 26 for Application v1 0 within each distribution table 36 In addi tion assume that the current distribution of allocations is 39 on leader server A 30 on follower server B 30 on follower server C and one in the free pool as indicated in the current distribution record 40 and the free pool 48 associated with the license code 26 for Application v1 0 within each distri bution table 36 Note also that in the embodiment of FIG 5 associated with each l
38. of leader server A and follower servers B and C in a server pool comprising three license servers in the example of FIG 5 after an authorization has been granted by follower server B according to an embodiment of the present inven tion FIG 7 is a generalized representation of the distribution tables of leader server A and follower servers B and C in a server pool comprising three license servers in the example of FIG 6 after a commuter authorization has been granted by follower server C according to an embodiment of the present invention FIG 8 is a generalized block diagram representation of an example network environment illustrating the storing of commuter authorization information according to an embodiment of the present invention DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the following description of preferred embodiments reference is made to the accompanying drawings which form a part hereof and in which is shown by way of illustration specific embodiments in which the invention may be practiced It is to be understood that other embodi US 6 968 384 B1 5 ments may be utilized and structural changes may be made without departing from the scope of the preferred embodi ments of the present invention Preferred embodiments of the invention relate to a system and process involving a pool of license servers for managing licenses to for example one or more protected software programs files or other data structures
39. on is valid The client computer may then use the protected software while coupled to or decoupled from the communication network until the com muter authorization lifetime expires These and other objects features and advantages of embodiments of the invention will be apparent to those skilled in the art from the following detailed description of embodiments of the invention when read with the drawings and appended claims BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 is a generalized block diagram representation of an example network environment according to an embodiment of the present invention FIG 2 is a generalized representation of a redundant license file RLF for the network environment of FIG 1 according to an embodiment of the present invention FIG 3 is a generalized representation of a license code contained in an RLF of FIG 2 according to an embodiment of the present invention FIG 4 is a generalized representation of a license code contained in an RLF and copied into a license table and a distribution table within a single license server for the network environment of FIG 1 according to an embodiment of the present invention FIG 5 is a generalized representation of an initial state of distribution tables of leader server A and follower servers B and C in a server pool comprising three license servers according to an embodiment of the present invention FIG 6 is a generalized representation of distribution tables
40. onnected from the net work It is a further advantage of embodiments of the present invention to provide a system and method for managing licenses on a network that allows a client computer to request and receive a commuter authorization from a license server while disconnected from the network allowing the client computer to run a protected software program while disconnected from the network These and other advantages are accomplished according to a system for managing licenses for protected software on 10 15 30 35 40 45 50 55 60 65 4 a communication network The system includes at least one client computer that is capable of being coupled to or decoupled from the communication network While coupled to the communication network a user of the client computer may request a commuter authorization to use the protected software At least one license server is also coupled to the communication network Each license server is programmed for managing a distribution of allocations to use the pro tected software In addition at least one of the license servers is programmed for granting a commuter authoriza tion in response to a request for a commuter authorization from a client computer if there is an available authorization After a commuter authorization is received by a client computer the client computer stores a commuter authoriza tion lifetime representing a time period for which the commuter authorizati
41. own the user may then communicate with a backup server to obtain an authorization message The backup server having a pre loaded copy of the license file and the license management program may then take over the license management func tions Alternatively in other prior versions of SENTINELLM systems a shell program or library of API functions could be configured to send a general poll to all servers coupled to the communication channel on which the poll is sent In response to a general poll any server computer having a license file containing license information corresponding to the protected software program whether or not the license information indicated that a license is available would send a reply to the requesting client computer The shell program or library of API functions associated with the requesting client computer would then respond to the first reply received from a license server having a license file storing license information for the protected software program If the replying license server contains an available license for the protected software program the replying license server provides an authorization message to the requesting client computer If the replying license server does not contain an available license for the protected software program the replying license server provides a message to the requesting client computer indicating that authorization to run the protected software program has not been
42. rancisco CA Feb 28 Mar 3 1983 pp 499 502 Houy T The Challenge of Selling Software on the Internet Electronic Software Distribution White Paper http Avww elan com corp esd htm Nov 4 1997 pp 1 6 IFOR LS and EZ LoK FAQ Product Information http www gradient com support techfaq ifor ezlok ezprod htm Nov 7 1997 pp 1 3 Harper Jr R Software Licensing For Installations With Multiple Microcomputers Abstract No C86000243 Computers amp Education 1985 vol 9 No 3 1 page Cooper F et al Software Protection and Pricing in a LAN Environment Abstract No 86032120 Jurimetrics Journal Winter 1986 vol 26 No 2 1 page Rainbow Technologies Sentinel License Manager Getting Started for Windows TCP IP and Novell NetWare Release 5 0 1997 pp i v 1 24 Rainbow Technologies Notice for SentinelLM 5 0 UNIX Customers 1997 1 page Rainbow Technologies Sentinel License Manager Integrator s Guide for NetWare Release 5 0 1997 pp i vi to IN 10 Rainbow Technologies Sentinel License Manager System Administrator Guide for NetWare Release 5 0 1997 pp i 1 to IN3 Rainbow Technologies Sentinel License Manager Reference Manual Release 5 0 1997 pp i 1 to IN12 Rainbow Technologies Sentinel License Manager Integrator s Guide for UNIX Release 5 0 1997 pp i 1 to IN10 Rainbow Technologies Sentinel License Manager Sy
43. rization independently of the at least one license server and wherein the requesting client computer is further pro grammed for detecting attempts to tamper with its internal clock and invalidating the commuter authori zation if tampering is detected 2 A system as recited in claim 1 wherein while the requesting client computer maintains a valid commuter authorization the requesting client computer may open the protected software multiple times including simultaneous instantiations of the protected software 3 A system as recited in claim 1 the at least one license server is further programmed for granting a commuter authorization to the requesting client computer and decre menting a count of available allocations only if there is an available allocation in the at least one license server 4 A system as recited in claim 3 the requesting client computer further including memory for storing commuter authorization information including the commuter authori zation lifetime and a check in value received from the granting license server when the granting license server grants the commuter authorization to the requesting client computer and US 6 968 384 B1 15 the granting license server further including memory for storing commuter authorization information including the commuter authorization lifetime and a check in value when the granting license server grants the com muter authorization to the requesting client computer 5
44. sers having access to the network Various forms of encryption techniques have been devel oped to inhibit usage of encrypted software by unauthorized users that do not possess a decryption program or key However such techniques typically require each authorized users to obtain or be passed a decryption program or key in 10 15 20 25 30 35 40 45 50 55 60 65 2 advance of usage of the encrypted program Accordingly such techniques can be prohibitively inconvenient for some computer and network environments where it is difficult or impractical to supply each authorized user with a decryption program or key or to decrypt a program for each user or usage Other software protection techniques have required legiti mate or authorized users to have a special hardware device or circuit installed in or plugged into their computer prior to usage of the protected software See e g U S Pat No 4 446 519 to Thomas Again such techniques can be pro hibitively inconvenient for some computer and network environments For example if the network environment is such that the authorized user must use multiple computers on the network then each computer must be provided with the special hardware device Moreover if the environment is such that computers having the special hardware device are not located in secure facilities then unauthorized users may be able to access the protected software by using the non secur
45. stem Administrator s Guide for INIX 5 0 1997 pp i 1 to IN4 Rainbow Technologies Sentinel License Manager Integrator s Guide for Windows TCP IP Release 5 0 1997 pp i 1 to IN12 Rainbow Technologies Sentinel License Manager System Administrator s Guide for Windows TCP IP Release 5 0 1997 pp i 1 to IN3 Rainbow Technologies Sentinel License Manager Integration Guide Release 6 0 1998 pp i to 130 Rainbow Technologies Sentinel License Manager Programmer s Reference Manual Release 6 0 1998 pp i to 187 Rainbow Technologies Sentinel License Manager System Administrator s Guide Release 6 0 1998 pp i to 62 Rainbow Technologies Notice for SentinelLM 6 0 UNIX Customers Mar 6 1998 pp 1 2 Rainbow Technologies SentinelLM License Management System Release 6 1 Release Notes Jan 15 1999 pp 1 7 Rainbow Technologies Sentinel Engineering Product Release Notes SentinelLM License Management System Version No 6 1 Aug 13 1998 pp 1 7 Rainbow Technologies Notice for SentinelLM 6 1 UNIX Customers Sep 18 1998 pp 1 2 Rainbow Technologies SentinelLM License Manager System Administrator s Guide Releae 6 1 1998 pp 1 61 Rainbow Technologies SentinelLM License Manager Developer s Integration Guide Release 6 1 1998 pp 1 164 Rainbow Technologies SentinelILM License Manager Evaluation G
46. step of commu nicating a request for a commuter authorization to use the protected software further including the step of selecting the commuter authorization lifetime 17 A method as recited in claim 10 the step of commu nicating a request for a commuter authorization to use the protected software further including the step of selecting the license server from which to request a commuter authori zation
47. t allows a client computer to request and receive a commuter authorization from a license server while dis connected from the network allowing the client computer to run a protected software program while disconnected from the network What is claimed is 1 A system for managing licenses for protected software on a communication network the system comprising at least one client computer capable of being coupled to the communication network for requesting a commuter authorization to use the protected software and for storing a commuter authorization lifetime representing a time period for which the commuter authorization is valid and at least one license server coupled to the communication network each license server programmed for managing a distribution of allocations to use the protected soft ware and at least one license server programmed for granting a commuter authorization in response to a request for a commuter authorization wherein the at least one client computer is configured with the protected software the protected software being independent of the at least one license server wherein after a commuter authorization is communicated from a granting license server to a requesting client computer the requesting client computer may use the protected software while coupled to or decoupled from the communication network until the commuter autho rization lifetime expires the requesting client computer utilizing the commuter autho
48. thorization In alternative embodiments of the present invention this can be accomplished by communi cating with the network administrator A user desiring to obtain a commuter authorization for a particular client computer 12 disconnected from the network first invokes a utility which generates fingerprint information 60 for the client computer 12 This fingerprint information 60 is con veyed to the network administrator through non networked communications such as by telephone e mail or the like In addition other information such as the requested software program is communicated to the network administrator Other information that may also be conveyed includes the license server 14 from which the commuter authorization will be requested and the requested time duration of the commuter authorization The network administrator then runs a utility 62 on any of the license servers 14 in the server pool that effectively sends a request for a commuter authorization to the targeted license server 14 If as described earlier an available allocation is found the distribution table 36 is updated so that the available allocations record 38 for the targeted license server is decreased by one and the allocations in use record 42 is increased by one The commuter authorization lifetime 56 and the check in value 58 are stored in persistent memory in the license server 14 In so doing one of the available allocations for a network authorization has be
49. uide Release 6 1 1998 pp 1 23 US 6 968 384 B1 Page 3 Rainbow Technologies SentinelLM License Manager Programmer s Reference Manual Release 6 1 1998 pp 1 191 Rainbow Technologies SentinelLM License Manager SentinelLM Developer s Guide Release 6 1 1998 pp i 127 Rainbow Technologies Notice for SentinelLM UNIX Customers Installing from CD Feb 26 1999 pp 1 2 Rainbow Technologies SentinelLM License Management System Release 6 2 Release Notes Feb 12 1999 p 1 11 Rainbow Technologies Notice for SentinelLM 6 1 UNIX Tandem Customers Feb 16 1999 pp 1 2 Rainbow Technologies Notice for SentinelLM 6 1 UNIX Customers Sep 23 1998 pp 1 2 Elan Computer Group Comparing Elan License Manager with other software license managers White Paper Jun 15 1995 pp 1 5 Elan Computer Group Elan License Manager Questions and Answers Aug 1995 G 0002556 0002562 pp 1 6 Elan Computer Group Elan License Manager Technical Overview Jul 1995 G 0002546 0002555 pp 1 9 Elan Computer Group Elan License Manager Integrator s Guide for Windows Release 5 0 rev Jan 31 1997 ELAN 002589 002597 pp i viii Elan Computer Group Elan License Manager System Administrator s Guide for Windows Release 5 0 rev Jan 31 1997 ELAN 002598 002602 pp i iv Elan Computer Group Elan License Manager Reference Manual Release 5 0 rev Jan 31
50. y reference herein In contrast pinging is disabled when a client computer 12 receives a commuter authoriza tion from a license server 14 Because neither the client computer 12 nor the license server 14 will respond to the lack of pinging when pinging is disabled communication between the client computer 12 and the server pool can cease for long periods of time At some point in time within the commuter authorization lifetime the client computer 12 may be re connected to the network In preferred embodiments of the present invention a user may then return the commuter authorization to the network by running a utility 54 that invokes the client library 52 associated with the requested software program 50 and selecting a check in function The client library 52 responds by sending a commuter authorization check in message to the license server 14 that initially granted the commuter authorization At that time the check in value 58 within both the client library 52 and license server 14 is set to indicate that the commuter authorization has been checked in There after the commuter authorization is disabled Furthermore within the license server 14 the number of available allo US 6 968 384 B1 13 cations is incremented by one and this change communi cated to the leader server If the granting license server is down at the time the client library sends the commuter authorization check in message this message will be sent to another
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