United States Patent [191

Transcription

1 United States Patent [191 Stilwell et al. [54] NETWORK DEVICE SIMULATOR [75] Inventors: Larry R. Stilwell. Fremont. N.H.; Vishwae V. Gokllale. Acton. Mass. [73] Assignee: Cabletron Systems, Inc.. Rochester. N.H. Appl. No.: 08/675,473 Filed: Jul. 3, 1996 Int. Cl G06F 11/30 US. Cl /500; 395/ Field of Search / /182.02; 364I/DIG. l 5,142, ,619,615 5,651,006 References Cited U.S. PATENT DOCUMENTS 8/1992 Patrick /200 9/1996 Dev et a / /1997 Pitchaikanj et al /11 7/1997 Fujino et al /408 OTHER PUBLICATIONS The SNMP Test Suite. Revision 4 by InterWorking Labs. Inc.. (Oct ). What is the Agent Simulator by Virtual Devices Incorpo rated. (Oct ). Network Tools Virtual Agent Page by Network Tools Products. (Oct ). Virtual Agent Overview." by Network Tools Products. (Oct ). Network Tools Press Release by Network Tools Products. (Oct ). Virtual Agent ScanOlD Application by Network Tools Products. (Oct ). Net Management Tool Oifered by Start-Up by Commu nicationsweek Interactive. httpd/wwwnetworktoolscom/ cornmweelchml (Oct ). US A [11] Patent Number: 5,907,696 [45] Date of Patent: May 25, 1999 Virtual Agent Creates Network Simulations by PCWeek Online. (Oct ). Numerical Methods in C. Chapter 14 entitled Statistical Descriptions of Data. by Press. W.H.. Teukolsky. S.A.. Vetterling. W.T.. and Flannery. B.R. published by Cam bridge University Press (1992). Ulam. S.M.: Monte Carlo Calculations in Problems of Mathematical Physics. in Modern Mathematics for the Engineer. E.F. Beckenbach. Second Series. McGraw Hill. New York (1961). Simple Agent: A SNMP Agent Simulator. Simple Soft Inc.. (Mar ).. "The Emanate Run-Time Extensible Agent System. SNMP Research International. Inc.. nateinlrohtml (Feb ). Why Emanate is better than SMUX. SNMP Research Internationzu. Inc.. (Feb ). Libraries. Utilities. and MIB Tools. SNMP Research Inter national. Inc.. (Feb ). The SNMP Agent. SNMP Research International. Inc.. httpzllwww.snmp.com/agentintro.html (Feb ). The Packaged Agent System." SNMP Research Interna tional. Inc.. (Feb ). Primary Examiner Kevin J. Teska Assistant Examiner A. S. Roberts Attorney Agent, or Firm-Wolf. Green?eld & Sacks. RC. [57] ABSTRACT Method and apparatus for creating the appearance of a network device and its communications. and in particular. an SNMP agent and its SNMP communications. A device dataset contains a plurality of counter variables having instance values which change over time and describe the behavior of the device on the network. A characterization file is created from the device dataset based on correlations among the variables and their instance values. The charac terization file is used to generate predicted instance values for a simulated device. 27 Claims, 24 Drawing Sheets 30 36A 32 DATASET 3 ill TOOLS AGENT ENGINE 35 I AGENT ADMINISTRATOR DATASETS ~34 CHARACTERIZATION FILES

2 US. Patent May 25,1999 Sheet 1 of 24 5,907,696 REAL NETWORK DEVICE 12 NETWORK MANAGEMENT 14 AGENT m NETWORK MANAGEMENT "\j STATION MANAGEMENT "5 DATA ' FIG. I 13 : STMULATED T,6 2 NETWORK DEVICE :/ NETWORK 1 1A1 MANAGEMENT STATION reads, pr uses to animate FIG. 2

3 US. Patent May 25, 1999 Sheet 2 of 24 5,907,696 23' r +";2g"; ENGINE J v & AGENT 13 /{ sfarf, E : $10 I - STATIC SIMULATION / P MANAGER /1 momforg AGENT I PLAYBACK Tcpnp L J ENG NE :lm NETWORK I \ 22A / l ' _"l _ ' creafe, l } modify: """ n. DATASETS NMS FIG. 3

4 US. Patent May 25, 1999 Sheet 3 of 24 5,907, A 33 S AGENT ADMINISTRATOR 35 S RUNTIME MODIFIER 32 DATASET l TOOLS AGENT ENGINE \ " 95% 4 DATASETS CHARACTERIZATION FILES 31 ~34 FIG. 4

5 US. Patent May 25, 1999 Sheet 4 of 24 5,907,696 SNMP QUERY SNMP DATA 12 S REAL, (REMOTE) NETWORK DEVICE MIB TCP/IP NETWORK NB \ / SNMP SNMP QUERY DATA 41 ( 42 j \J SIMULATION MANAGER CLONED DA ET CLONEISINGLE ms 8 QUERY J RECORD-MULTIPLE \F _ QUERIES CHARACTERIZATION DATASETS EDITOR/ TOOLS CHARACTERIZE SIMULATE FIG. 5

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7 U.S. Patent May 25, 1999 Sheet 6 of 24 5,907, "CL0NE DEvICE" SELECTED & 52 ENTER AGENT IP ADDRESS OF DEvICE TO BE CLONED i 53 ENTER DATASET NAME 54 START LOADING L 55 SNMP QUERY DEvICE FOR NAMES OF ALL VARIABLES I, 56 RECEIVE RESPONSE W/ NAMES SNMP QUERY DEVICE FOR INSTANCE VALUES 58 V RECEIVE RESPONSE J 59 SAVE NAMES AND INSTANCE values IN DATASET F1617

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11 U.S. Patent May 25, 1999 Sheet 10 0f 24 5,907,696 SET SAMPLE COUNT AND SAMPLE INTERVAL ESTABLISH COMMUNICATION TO DEVICE 14? QUERY ONCE TO GET NAMES OF COUNTER VARIABLES 142 I43 I45 \ QUERY EACH COUNTER OBTAIN DIFFERENCE VALUE 146 UNTIL SAMPLE COUNT RE ACHED DIVIDE DIFFERENCE VALUE BY SAMPLE INTERVAL 147 STOP WHEN ALL VARIABLES ARE DONE I DECIDE WHICH VARIABLES ARE CORRELATED FROM THEIR CORRELATION COEFFICIENTS CALCULATE Probrs AND Probd FOR EACH VARIABLE PAIR. IF EITHER ONE OF THEM HAS A VALUE LESS THAN O.I THERE IS A CORRELATION AMONG THE SELECTED VARIABLES FOR EACH VARIABLE, COMPUTE MEAN AND STANDARD DEVIATION FOR EACH GROUP OF CORRELATED VARIABLES, COMPUTE Kij PARAMETERS._ZK !) r148 yl } UK] I 1490 GENERATE FREQUENCY TABLE FOR EACH VARIABLE WITH THE RANGE DIVIDED INTO M INTERVALS FIG. I1

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16 US. Patent May 25, 1999 Sheet 15 0f 24 5,907,696 CONNECT TO NETWORK 170 I72 OPEN DATASET l! I 73 READ OBJECT NAMES AND FIRST INSTANCE VALUES FOR ALL VARIABLES 1N DATASET l, 174 CLOSE DATASET 175 SEND FIRST INSTANCE VALUE FOR EACH VARIABLE -_-_J END 5 SIMULATlON DISCONNECT NETWORK J78 RETURN TO > SIMULATION MANAGER FIG. 16

17 US. Patent May 25, 1999 Sheet 16 of 24 5,907,696 CONNECT TO W200 NETWORK NO CONNECTED 20! 202 OPEN DATASET 203 READ VARIABLE NAMES, FRAME COUNT FRAME TIME AND FIRST INSTANcE VALUE FOR EACH VARIABLE I, 204 CURRENT FRAME =1 TIMER = O START TIMER 205 CHECK FOR QUERY RESPOND TO QUERY WITH VARIABLE INSTANCES REQUESTED WHICH CORRESPOND TO INSTANCES IN CURRENT FRAME OF DATASET II 208 L INcREMENT TIMER. \I! L SET CURRENT FRAME BASED ON TIMER [T2090 II PLAYBACK CONSOLE! ADJUST CURRENT FRAME AND TIMER 209c 20gb LDISCONNECT NETWORK I RETURN TO SIMULATION MANAGER FIG. 17 /_,209c! 209a

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