RTI Shapes Demo - Community RTI Connext Users
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1. a Start a second Shapes Demo color ey Apply QoS from Profile We will refer to this copy of Pu Choose the profie BLUE x the application as iens Defocit Defouit Subscriber1 GREEN QoS Values YELLOW TA b Under Subscribe click on CYAN ab MAGENTA ici Circle e Strength Lease Duration ms ORANGE 1 INF c In the Create New Sub mE Durabil History scriber window 30 e bend iS Gal a 0 e Click OK Use all the a z3 defaults Relabiity You will see 6 red circles with Content Filter Topic Read method to use blue borders on the Subscriber Use filter Read TakeO canvas mirroring the move ments of the circle in the Pub Cox lisher canvas The leading circle indicates the current position of the published circle The other circles are the historical samples kept by Connext You can see the difference between historical data and new data looking at the thickness of the border You can also hide historical data by selecting Hide His tory from the Controls menu Publish Subscribe Example Your windows should look similar to Figure 4 1 Figure 4 1 Publisher and Subscriber Displays RTI Shapes D jomain RTI s E File View Publish Subscribe Controls Help File View Publish Subscribe Controls Help Square Circle Triangle Square Circle O Delete All P lishi Name Type Color Partitions Read Take QoS Settings Reliability I N2. Color Key PURPLE Apply QoS from Profile Choose the profile Default Default Liveliness AUTOMATIC Z Lease Duration ms INF History Reliability Read method to use Use filter 8 Read TakeQ Content Filter Topic Apply QoS from Profile Choose the profile Default Default Y Reliability r Liveliness IV Exdusive AUTOMATIC Ej strengt Lease Duration ms Lili INF Durability Histor VOLATILE Ad 6 Time based Filter ms Deadline ms 0 Lifespan ms Content Filter Topic IT Use filter r Read method to use Read C TakeO L ox c ting for the subscriber is the time at which the subscriber application will fail over to the lower strength publisher application In Publisher2 click on Pause Publishing 4 15 sejduupxa p Examples 4 6 4 6 1 4 16 After 2000ms Subscriber1 will show a requested deadline missed message in its Output tab and at the same time fail over to display the movements of the red cir cle in Publisher1 Publisher2 initially had exclusive ownership of the red circle instance because it had a higher strength However this ownership was lost to the lower strength Publisher1 when the subscriber missed a deadline This is especially useful if a publisher is unable to gracefully shutdown and relinquish its ownership 5 In Publisher2 click on Resume Publishing Subscriber1 s red
3. r QoS Values Time based Filter ms 0 Reliability Lifespan ms Color Key PURPLE BLUE C RED C GREEN vaLow CYAN C MAGENTA 30 Partitions Content Filter Topic Read method to use Use filter le Read C TakeQ Lease Duration ms INF History 1 Deadline ms INF Lifespan ms Time based Filter ms W Reliability INF Content Filter Topic use filter Read method to use 8 Read Take CC E Examples Figure 4 4 Different Ownership Strengths Publisher strength 1 Publisher2 strength 3 UE D E RTI Shap E File View Publish Subscribe Controls Help File View Publish Subscribe Controls Help Square Square Triangle A Triangle Square F Square F Circle Triangle VEE SS ER File View Publish Subscribe Controls Help A lete All Publish Pause Publishin Square Hide History Circle Configuration S Triangle Name Type Color Partitions Read T al ke QoS Settings Reliability I Triangle Pub ORANGE _ 3 Default Default True 1 Square F Circle Triangle Conte 00 A RUN Delete All Ready on domain 0 Pause Publishing 2 Configuration m Name Type Color Partitions Read Take QoS Settings Reliability t Triangle Sub lt Read Default Default False Subscriber 4 Use your mouse in Publisher2 to drag the triangle around t
4. ability and History 200 a Under Subscribe click on Circle b In the Create New Subscriber window e Use the drop down list box to change Durability to Transient Local Check Reliability e Set History to 200 e Click OK File View Publish Subscribe Controls Help 5 Watch the Subscriber canvas You will see a shadow of objects Triangle printed out in a continuous pattern Em The shadow results from the sub Square scriber showing the last 200 samples ange from the publisher s history queue GREEN 6 To stop showing the shadow trail of s ER samples on Subscriberl click on LE p ww Hide History Name Type Color Partitions Read Take QoS Settings Reliability Read Defaut Defaut True 4 4 19 sejduupx3 p Examples 4 6 4 4 20 Time based Filtering Example Sometimes subscribers are located on slower or more remote systems that cannot han dle the amount of data that the publisher is capable of sending For example consider a system where a central command center is publishing high resolution aerial photos of a geographic area once every 30 seconds and a soldier with a handheld computer is trying to subscribe to the data In this case the handheld computer does not have the band width to handle the command center s send rate With time based filtering the hand held computer can throttle the data so that it only receives data once every 5 minutes 1 Start two copies of Shapes Demo which we will call Pu
5. TRANSIENT VOLATILE LOCAL TRANSIENT PERSISTENT VOLATILE v incompatible incompatible incompatible TRANSIENT v v incompatible incompatible LOCAL Publisher TRANSIENT v incompatible PERSISTENT v v Note If you select Durability you must also select Reliability this applies to the pub lisher and subscriber Publish and Subscribe Task Panes 3 3 5 3 3 3 5 4 Table 3 2 3 3 5 5 Time Based Filter Time Based Filter is only available when creating a subscriber It is the minimum sepa ration time in milliseconds that the subscriber wants between data updates Any data arriving within this time interval will be discarded Where possible the publisher will not publish the data Valid settings range from 0 to 31 536 000 000 ms 1 year The Time Based Filter value must be less than the Deadline value Section 3 3 5 7 Reliability If Reliability is selected for a publisher the default setting for a publisher the publisher will attempt to deliver all data sent If data has not been received by the subscriber due to a communication error the middleware will retransmit the data If Reliability is not selected the publisher will use best effort communication and will not retransmit any missing data If Reliability is not selected for a subscriber the default setting for a subscriber the sub scriber will not expect lost data to be resent If Reliability is selected for a subscriber the subscriber
6. Utilities User s Manual for more details Under the hood data centricity extends traditional publish subscribe messaging with an in memory data management layer Applications operate on locally cached objects The middleware synchronizes caches by publishing updates and subscribing to data of interest Information is efficiently distributed across nodes based on each application s content timing and reliability requirements RTI s Professional Services team is here to help you meet the challenges of developing complex networked applications Building upon RTI s market leading products RTI Professional Services provides customers an important head start and competitive edge we re here to help you mitigate project risk increase productivity and deliver quality often on a shortened schedule The RTI Professional Services team of highly trained and specialized engineers has been helping customers develop a broad range of data critical applications for more than a decade Our past engagements include custom middleware for industrial automation performance optimizations for financial trading systems integration of shipboard net works design and integration of robotic cranes and the architecture for a 24x7 train dis patch call center Our team draws on experience building systems not just networks and can provide insight at any stage in the product life cycle RII also offers extensive training RTI s Quickstart course has over 1 000 gradu
7. Size 30 Partitions ownership and a strength of 1 Create new Publisher Triang Apply QoS from Profile Choose the profile Default Defauit QoS Values Ownership V Exdusive Strength Liveliness AUTOMATIC V Lease Duration ms INF Durabili History 3s is Deadline ms INF Lifespan ms INF 7 Reliability Content Filter Topic Read method to use akeQ Cancel Ownership Example In one of the other Shapes Demo windows create a tri angle subscriber with Exclu sive ownership We will call this window Subscriber1 a Under Subscribe click on Triangle b In the Create Subscriber window New e Check Exclusive e Click OK You should see 6 orange triangles with blue bor ders moving around in the Subscriberl canvas So far this is similar to the publisher subscriber exercise In the third window create an orange triangle publisher with Exclusive ownership and Strength 3 We will call this window Publisher2 a Under Publish click on Triangle b In the Create Publisher window ORANGE for New e Select Color e Check Exclusive and set Strength to 3 e Click OK You should see an orange triangle in Publisher2 s canvas PURPLE BLUE C RED C GREEN C YELLOW C CYAN C MAGENTA C ORANGE r Initial Size B r Apply QoS from Profile Choose the profile Default Default
8. and need to delete a single pub lisher or subscriber select the item in the Legend tab and press the Delete key on your keyboard 1 In Publisherl create a red circle publisher with Exclusive Own Create new Publisher Circl olor Key Apply QoS from Profile ership Strength 1 Deadline E Hikari 400 ms Default Default a In Publisher1 under Publish click on Circle 5 b In the Create New Publisher Lease Duration ms window ai History Select RED for Color Check Exclusive e Set Strength to 1 Set Deadline to 400 ms a S En Y Use filter 9 Read TakeQ Click OK Deadline ms 400 espe F Reliability INF e i e Failover Example 4 In Publisher2 create a red circle publisher with Exclusive Own ership Strength 3 Deadline 400 ms a Under Publish click on Circle b In the Create New Publisher window e Select RED for Color Check Exclusive e Set Strength to 3 e Set Deadline to 400 ms e Click OK In Subscriberl create a circle subscriber Exclusive selected Deadline 2000 ms a Under Subscribe click on Circle b In the Create New Subscriber window e Check Exclusive e Set Deadline to 2000 ms e Click OK In the subscriber canvas you should see red circles that mir rors the movement of the one in Publisher2 This happens because the Publisher2 s circle has a higher strength that Publisherl s The deadline set
9. circle should immediately switch to tracking the movements of Publisher2 More Experiments Please feel free to experiment and run tests using the other QoS options in the Create New Subscriber and Create New Publisher windows Described below are a few other interesting behaviors to test Content Filtered Topics Example A content filtered topic is a very useful feature if you want to filter data received by the Subscriber It also helps to control network and CPU usage on the subscriber side because only data that is of interest to the subscriber is sent For example assume your application is a radar monitor that draws flights detected within a 20 mile radius The application can subscribe to the track data with a content filtered topic for a 20 mile radius on the coordinates of all flights With the filter only coordinates that are within the 20 mile radius will be sent to the application 1 Start two copies of Shapes Demo which we will call Publisher1 and Subscriber1 If you are reusing demo windows from the previous section make sure to delete any existing publishers and subscribers under Controls click Delete AIl 2 In Publisher1 create a circle publisher any color a Under Publish click on Circle b In the Create New Publisher window click OK More Experiments 3 In Subscriberl create a circle subscriber with a content fil tered topic a Under Subscribe click on Circle b In the Create New Sub
10. ee beris 3 14 3 5 Shapes Demo s Workspace eco aee ee tet addi ia a dene 3 15 M ele Mec c E 4 1 4 Publish Subscribe Examples eir paiesi nene nennen 4 1 42 Multiple Instances Example sse nennen nennen 4 4 43 Ownership Example eee eee ie er etd eme Re ie ends 4 8 44 Failure Detection Example nion eii nte rh e teh eie ite 4 11 45 Pailoyer Example 5 4e eren tene eee nhe erede te etude 4 14 4 6 More Experiments recen n petii ei Hide e br EE Re bre e eta ehe de ea tat 4 16 4 6 1 Content Filtered Topics Example sees eee 4 16 462 Lifespan Exarmiplez eret e He tenete pee inre eoe dente eaa 4 18 4 6 3 Reliability and Durability Example ssssseseeeeeeeeeeeenenes 4 19 4 64 Time based Filtering Example sess eee enn 4 20 f Xele ld4 rc 5 1 Running from the Command Line A 1 Itoubleshoofllng 45 rie daea see tege d ducc appa neue B 1 B L Windows Security Alert rie Dude fe nei irre estie dt etre eats sb eoe tret als B 1 B 2 Running without an Active Network Interface sees eee nen B 2 Chapter 1 Introduction Welcome to the RTI Shapes Demo This demonstration application is a self contained introduction to the elegance and power of publish subscribe networking It goes beyond simple publishing and subscribing however This demo will also give you a glimpse of the goals and capabili
11. expects all data updates reliably It listens for heartbeats from the publisher and responds with either a positive acknowledgement to indicate data receipt or a negative acknowledgement to initiate retransmission of missing data The publisher and subscriber must use compatible settings as described in Table 3 2 Valid Combinations of Reliability Subscriber Reliability not selected Reliability selected default BEST EFFORT RELIABLE Reliability not selected v incompatible default BEST EFFORT Publisher Reliability selected v v RELIABLE Liveliness and Lease Duration Liveliness is used to detect the state of the publisher even when it is not actively sending data For a publisher the Liveliness value is the maximum time interval within which a pub lisher will signal that it is active 3 9 ouJegq eui 6ursn Installing and Using Shapes Demo 3 3 5 6 3 3 5 7 3 3 5 8 3 10 For a subscriber the Liveliness value is the maximum time interval within which a sub scriber expects to be notified that the publisher is alive A subscriber s Liveliness must be greater than or equal to the publisher s Liveli ness Valid settings range from 0 to 31 536 000 000 ms 1 year or INF for infinity the default History History controls the amount of data that is kept in the send queue This is normally used in connection with Durability and or Reliability If Durability is
12. how long data samples are considered valid You can use it to prevent sending data that is considered too old to be valid The default setting is an infi nite duration meaning the data will never expire 1 5 6 48 RTI Shapes De m main QUU od E RTI Shapes Demo Domino eB X File View Publish Subscribe Controls Help File View Publish Subscribe Controls Help Publish Publish Square Square Circle Circle Triangle Triangle Subscribe Subscribe Li E Square Circle Circle Triangle Triangle Controls Controls Delete All Delete All Resume Publishing Pause Publishing Hide Hi Hide History Configuration Configuration d Start two copies of Shapes Demo which we will call Publisher1 and Subscriber1 If you are reusing demo windows from the previous section make sure to delete any existing publishers and subscribers under Controls click Delete AI In Publisher1 create a circle publisher any color with History 100 Lifespan 1000 ms a Under Publish click on Circle b Set History to 100 and Lifespan to 4000 c Click OK In Subscriberl create a circle subscriber with History 100 a Under Subscribe click on Circle b Set History to 100 c Click OK Drag the shape around on Publisher1 s canvas On Subscriber1 s canvas you will see a shadow of objects printed out in a con tinuous pattern The shadow is caused by the subscriber showing the last 100 data samp
13. is specified both in the base profile and in the current profile the one in the current one is used Publish and Subscribe Task Panes 3 3 5 3 3 5 1 Setting QoS Values You can control the QoS values for the publisher and subscriber in two ways 1 You can modify the QoS values in a profile and then apply that profile as described in Section 3 3 4 2 You can explicitly set some pos Values QoS values directly in the Create New Publisher Sub Ownership Liveliness scriber dialog as seen in Exdusive AUTOMATIC this screenshot and Lease Duration ms described below Values set 0 INF in the dialog override val Durability History ues in the profile VOLATILE Y 1 Deadline ms INF Lifespan ms V Reliability INF Exclusive Ownership and Strength Ownership determines whether or not the instance specified by color of the Topic is exclusively owned by one publisher that is if multiple publishers of Red Squares can send data to this instance at the same time or not If the Exclusive checkbox is selected for a publisher the Strength box will become available for input The publisher with the highest Ownership Strength number is the only publisher that can write data to this instance If the Exclusive checkbox is selected for a subscriber it means that the subscriber only wants data from one publisher the one with the highest ownership strength The publisher and subscriber must use the
14. scriber window e Check Use filter e Click OK You will see a shaded rectangle appear in the subscriber can vas This is the filter for the coordinates of the Circle topic The subscriber will receive position data for the Circle only when it is with the area defined by the content filter r Color Key C PURPLE BLUE C RED GREEN C YELLOW C cy C MAGENTA C ORANGE r Initial Size Partitions Create new Subscriber Circle r Apply QoS from Profile Choose the profile pefauit Defauit z r QoS Values J Exdusive Strength Lease Duration ms 1 INF Durability VOLATILE hd 6 Time based Filter ms Deadline ms 0 INF Lifespan ms 4 To see the effect of dynamic filters use your mouse to move and resize the shaded area in Subscriber1 Figure 4 6 Content Filtered Topic Example RII nain File View Publish Subscribe Controls Help Square Circle Triangle Square Circle Triangle Delete Al E Pause Publishing Hide History Configuration he m Name Type Color Read Take QoS Settings Read Take QoS Settings Cirde Default Default lt Pub Output Legend ReadQ Default Default Ready on domain 0 4 17 Examples 4 6 2 4 18 Lifespan Example TheLi fespan QoS controls
15. the Shapes Demo window on the screen posY Specifies the Y position of the Shapes Demo window on the screen Specifies how often the publisher should send data in ms pubInterval integer H 9777 Default 50 ms Specifies how often the subscriber should look for data in ms subInt l int subInterva integer Default 50 ms Specifies an XML configuration file k Fil EiT Worsspaceti e 1 9 Default See Shapes Demo s Workspace on page 3 15 A 2 Appendix B Troubleshooting B 1 Windows Security Alert When you run the demo you may encounter a Windows Security Alert dialog Simply click Allow Access Windows Firewall has blocked some features of RTI Shapes Demo on all public private and domain networks Name RTI Shapes Demo Publisher Real Time Innovations Inc Path C program files x86 rtirti shapes demo 4 5x bin tishapesdemo exe Y86win32vs2005 ti Allow RTI Shapes Demo to communicate on these networks V Domain networks such as a workplace network V Private networks such as my home or work network 7 Public networks such as those in airports and coffee shops not recommended because these networks often have little or no security What are the risks of allowing a program through a firewall B 1 B 2 Running without an Active Network Interface If you run Shapes Demo on a system that does not have an active network interface you m
16. RII Shapes Demo A Demonstration of RTI Connext User s Manual Version 4 5 f t Your systems Working as one 2006 2012 Real Time Innovations Inc All rights reserved Printed in U S A First printing Feb 2012 Trademarks Real Time Innovations and RTI are registered trademarks of Real Time Innovations Inc All other trademarks used in this document are the property of their respective owners Copy and Use Restrictions No part of this publication may be reproduced stored in a retrieval system or transmitted in any form including electronic mechanical photocopy and facsimile without the prior written permission of Real Time Innovations Inc The software described in this document is furnished under and subject to the RTI software license agreement The software may be used or copied only under the terms of the license agreement Technical Support Real Time Innovations Inc 232 E Java Drive Sunnyvale CA 94089 Phone 408 990 7444 Email support rti com Website https support rti com Contents ME MAO GUCTION ccm 1 1 1 1 Guide to this D cum titas isien ina ae e aaea a aa Eoaea tenen sen ens 1 2 1 2 Goals of the Demonstration cccccccccsesssessecssessecsscssesecesesesseseseceecseessecssessecsecsasenscsaseesereaes 1 2 2 Background Information esses 2 1 241 Communication Models in Networking Middleware sss 231 22 Connext O
17. Read Take QoS Settings Reliability 1 m Output Legend True True Crde Sub Read Default Default False Ready on domain 0 Ready on domain 0 Subscriber Notice that we did not have to do anything in Subscriber1 to start receiving the green circle s data That s because the subscriber of a topic Circle in this case gets all data sent for all instances of the topic The green circle was just another instance of the topic Circle so the subscriber received this new data automati cally 5 Create another red circle publisher in a new window a Start a third Shapes Demo We will refer to this copy of the application as Publisher2 b Under Publish click on Circle c In the Create New Publisher window e Select RED for Color Click OK Multiple Instances Example Figure 4 3 Two Publishers and One Subscriber Publisher Publisher2 RTI Shapes D Domain 0 File View Publish Subscribe Controls Help Color Partitions Read Take QoS Settings Reliability I Read Defaut Defaut False Subscriber We now have multiple publishers updating the same instance Red of the topic Circle You ll see that the red circle in Subscriber1 s canvas flickers between differ ent locations This happens because the subscriber is receiving position data from both of the publishers and is trying to display them at the same time Details on
18. YervieW a nee rende eie eh ce E E A e e eed ines Bove ERA 2 3 DDIM Quality Of Serviee s ae tein ee eeu eda ete e t E 2 3 23 Publish Subscribe Simple Analogy sss ee eene nennen 2 4 24 Publish Subscribe Complex Analogy sess eene nennen 2 5 25 Publish Subscribe Example Application esse eee eee een 2 6 3 Installing and Using Shapes Demo 3 1 9 1 Installations eet PEE etre eee E re latet P eee 3 1 8 2 Running Shapes Demo da eite rede e ire ee rh eret ar e ete 3 1 3 3 Publish and Subscribe Task Panes essent nennen nennen nnne 3 3 9 3 14 COlOP ia Sci RI t st e melins 3 4 3 3 2 Initial Size ie SRI ERR etcetera ea eee RES 3 4 3 3 3 Partitions ione ted eet pete e eost Deest epo NER dlavho ees 3 4 334 Apply QoS ront Profiles teg iei eines ids 3 5 3 3 5 Settings QOS Values aine eerte tee testi roten certe irit ire irata 3 7 3 3 6 Using a Content Filtered Topic neret etre pterea rens 3 11 3 37 Controlling the Read Method sse eene nnns 3 11 344 Other Controls eret ee nU he ee es e tens 3 11 34451 iDeletezAITL ice mte tente e e tee Ee tele eet ee een 3 11 3 42 Pause Publishing siehe Ree hen E with alienate ales 3 12 34 3 Show Hide History eene ee i a it ede een 3 12 94L4 Configuratlon cocto eoe etn ette eon eine reen dentis 3 12 3 45 Outputand Legend Tabs eie niit
19. ame Type Color Partitions Read Take QoS Settings Reliability E Cirde Pub RED _ Default Default True 1 Cirde Sub B ReadQ Default Default False 1 Ready on domain 0 Ready on domain 0 Publisher Subscriber 3 Test real time data delivery To show that the subscriber is receiving real time data move the cursor over the Publisher s red circle and click the mouse button This will stop the red circle in the publisher canvas Drag the cursor and move it around while holding down the mouse button The red circles on the subscriber canvas should exactly mirror your mouse movements Congratulations you have just finished the first exercise which illustrates basic pub lish subscribe functionality If you plan to continue with the next exercise leave the two demo windows running The next exercise will use the red circles 4 3 Examples 4 2 4 4 Multiple Instances Example Instances are useful when you are dealing with data that is unpredictable in terms of its creation and deletion e g aircraft airplane flight tracks and shipment tracking Flights and shipments can come and go The application has no way of knowing when or how many flights shipments show up Connext provides rich semantics that can be used to track monitor and check the state new deleted no writers etc of individual instances Some of the possible notifications are displayed in the Output tab Publish
20. ates as of this writing On site training is available public training schedules are available from WWNW rti com Finally RTI has many professionals ready to answer your questions Email sales rti com with any business or technical questions you may have We will happily support a no obligation on site evaluation 5 3 IL Inoqv G About RTI 5 4 Appendix A Running from the Command Line In some cases you may want to run Shapes Demo from the command line 1 Open a command prompt and navigate to the folder where Shapes Demo is installed 2 Enter the following command gt scripts rtishapesdemo command line options Table A 1 describes the command line options These options take precedence over con flicting settings in the configuration file if any For example if the configuration file specifies domain ID 1 and you enter domainlId 2 then domain ID 2 will be used Table A 1 Command line Options eur PUDLUWUOD Y Option Description compact Starts Shapes Demo using a compact view For different copies of Shapes Demo to communicate with each other they must use the same domain ID The default domain ID is 0 if you need to use a different domain ID you must use the same value for all copies of Shapes Demo that need to commu nicate with each other The ID is an integer value 0 or higher domainId ID help Lists the command line options posX Specifies the X position of
21. ay see this warning WARNING A Create participant failed Trying with no network mode Participant creation failed because by default Shapes Demo uses UDPv4 which is not available if there is no active network interface After you select OK Shapes Demo will create a participant using shared memory instead of UDPv4 B 2
22. blisher This provides automatic failover if a strong publisher fails all subscribers immediately receive updates from the backup weaker pub lisher Durability Publishers can declare durability a parameter that determines how long previously published data is saved Late joining subscribers to durable publica tions can then be updated with past values Other QoS parameters control when the middleware detects nodes that have failed sug gest latency budgets set delivery order attach user data prioritize messages set resource utilization limits partition the system into namespaces and more Connext QoS facilities offer unprecedented flexibility and communications control Publish Subscribe Simple Analogy The publish subscribe communications model is analogous to that of magazine or newspaper publications and subscriptions Think of a publication as a newspaper such as New York Times The Topic is the name of the periodical New York Times The type specifies the format of the information weekly printed magazine or daily newspa per The user data is the contents text and graphics of each sample weekly or daily issues The middleware is the distribution service US Postal service or a paper delivery service that delivers the reading material from where it is created a printing house to the individual subscribers people s homes This analogy is illustrated in Figure 2 1 Note that by subscribing to a publication sub
23. blisherl and Subscrbiber1 If you are reusing demo windows from the previous section make sure to delete any existing publishers and subscribers under Controls click Delete AIl 2 In Publisher create a circle publisher any color a Under Publish click on Circle b In the Create New Publisher window click OK 3 In Subscriber1 create a circle subscriber History 1 Time Based Filter 1000 ms a Under Subscribe click on Circle b In the Create New Subscriber window e Set History to 1 Set Time Based Filter to 1000 e Click OK You will see the circle jump once every second instead of a fluid movement In this case the publisher is only sending data to the subscriber once a second according to the subscriber s time based filtering Chapter 5 About RTI Thank you for taking the time to explore RTI Connext For more information please visit RTI s web site ww w rti com or send email to info rti com Connext solutions provide a flexible data distribution infrastructure for integrating data sources of all types At its core is the world s leading ultra high performance distrib uted networking DataBus It connects data within applications as well as across devices systems and networks It also delivers large data sets with microsecond perfor mance and granular quality of service control Connext is standards based and an open architecture connecting devices from deeply embedded real time platforms to enter prise server
24. cs A Topic has a name and a type the type defines the structure of the data Ci Circle and Triangle Clicking one of these options will open a dialog that allows you to Shapes Demo can publish and subscribe to three Topics Square Triangle set the QoS for the publisher subscriber E Exdusive Strength 0 Durabili V Reliability Lifespan ms INF Content Filter Topic Read method to use Use filter 8 Read TakeQ J ewe Installing and Using Shapes Demo 3 3 1 3 3 2 3 3 3 3 4 Color Color is selectable only when creating a pub lisher You can use color to represent different instances of the same topic shape The Color key area is grayed out for subscrib ers The subscriber of a topic will receive all data sent on all instances of the topic Initial Size A shape s color is used as a key sim ply a way to distinguish between data for multiple instances of the same shape topic Data that belongs to the same instance in the topic shape will have the same key color The initial size field allows you to control how big the shape is Partitions You can use partitions to dynamically isolate and group publishers and subscribers If a publisher has a partition then only subscribers with that same partition will receive data from that publisher The demo supports four partitions A B C and D Partitions support regular expre
25. d fault tolerance natural Finally the intent declaration process provides an opportu nity to specify per data stream Quality of Service QoS requirements Properly imple mented publish subscribe middleware delivers the right data to the right place at the right time In summary client server middleware is best for centralized data designs and for sys tems that are naturally service oriented such as file servers and transaction systems Client server middleware is not the best choice in systems that entail many often poorly defined data paths Message passing with send that there semantics map well to systems with clear simple dataflow needs Message passing middleware is better than client server middleware at free form data sharing but still require the application to discover where data resides Publish subscribe by providing both discovery and messaging implements a data centric information distribution system Nodes commu nicate simply by sending the data they have and asking for the data they need Connext Overview 2 2 2 2 1 Connext Overview Connext presents a publish subscribe integration model that connects anonymous infor mation producers publishers with information consumers subscribers The overall distributed application is composed of processes called participants each running in a separate address space possibly on different computers A participant may simultane ously publish and subscribe to
26. e DataW riter s Liveliness is set to AUTOMATIC with a lease duration of 1 second The DataReader has a History depth of 100 samples and is set to RELIABLE IJ RTI Shapes Lib Ownership Exclusive This profile sets Ownership to EXCLUSIVE for both the DataReader and the DataWriter The DataWriter s Own ership Strength is set to 4 M RTI Shapes Lib Durability Volatile This profile sets Ownership to VOLA TILE and History of 100 samples for both the DataReader and the DataWriter The DataReader is set to be RELIABLE I RTI Shapes Lib Durability Transient This profile sets Ownership to TRAN SIENT for both the DataReader and the DataWriter RTI Shapes Lib Durability Persistent This profile sets Ownership to PER SISTENT for both the DataReader and the DataWriter L MonitorDemoLibrary Default MonitorDemoLibrary SamplesRejectedScenario MonitorDemoLibrary FixedSamplesRejectedScenario tThese profiles are used in the tutorial for RTI Monitor You will find RTI SHAPES DEMO QOS PROFILES xml in the Shapes Demo installation directory or My Documents N RTINRTI Shapes Demo version depend ing on your operating system If you open RTI SHAPES DEMO QOS PROFILES xml you can see that the profiles shipped with this demo have the property base name which points to another profile That means that the profile will use all the QoS settings of the profile pointed by base name plus the QoS settings explicitly specified If a property
27. e Edit button the default XML editor will open allow ing you to correct the file and correct the error 3 4 5 Output and Legend Tabs There are two tabs at the bottom of the demo application window 1 The Legend tab shows you the publishers and subscribers created for the demo and their QoS settings If you right click on a publisher entity in the Legend tab you can access these commands Pause resume publishing see Section 3 4 2 e Dispose data and delete the DataWriter Unregister data and delete the DataWriter If you right click on a subscriber in the Legend tab you can access a command to delete the DataReader Another way to delete a publisher or subscriber is to click on it in the Legend tab and press the Delete button on your keyboard Name Type Color Partitions Read Take QoS Settings Reliability Square Pub BLUE Default Default True Cirde Pub YELLOW Default Default True Square Sub A Read lib Shapes De False Triangle Sub TakeQ Default Default False 4 Output 1 When you press Delete the current setting for the WriterDataLifecycle QoS policy s autodispose unregistered instances field determines if the DataWriter s data is disposed before it is unregis tered If autodispose unregistered instances has not been changed via a QoS profile the default setting will cause the data to be disposed and unregistered 3 14 Shapes Demo s Workspace 3 5 Dispose vs U
28. efauit Square nw QoS Values b In the Create New Publisher eee ae window e a Lease Duration ms 0 INF e Select CYAN for Color F TU e Set Deadline to 200 ms 200 e Click OK Nese Reliability INF Content Filter Topic Read method to use Use filter 9 Read TakeQ Ce JL om se duupX3 7 Examples 4 12 2 Create a squares subscriber in Subsriberl with Deadline 4000 ms a Under Subscribe click on Square b In the Create New Create new Subscriber Square e OON COE OM CON S Ck Apply QoS from Profile Choose the profile Default Default X QoS Values Ownership Liveliness Exdusive AUTOMATIC zm Subscriber window Strength Lease Duration ms 2 cm INF e Set Deadline to 4000 ms Durabilty History VOLATILE x 6 Click OK Time based Filter ms Deadline ms 0 4000 You ll see a cyan set of 6 f lt Reliability ana squares moving around Content Filter Topic Read method to use Use filter Read C TakeQ Subscriber1 s canvas This set of squares mirrors the movement of the cyan square in Publisherl s canvas along with 5 historical samples Note The subscriber s deadline must be greater than or equal to the publisher s deadline If not an Incompatible QoS Deadline on Square error message will be displayed in the Output tab of the Subscriber demo application 3 In Publisher1 s Controls sub panel click Pause Publishing The cyan square in S
29. emo windows running one is publishing red circles and the other is subscrib ing to circles 2 In Subscriber1 choose Delete All from the Controls Menu 3 Create a circle subscriber with History 1 a In Subscriber1 under Subscribe click on Circle Multiple Instances Example b In the Create New Subscriber window Change the History field from 6 to 1 e Click OK You should now see one red circle moving in each instance of Shapes Demo Create a green circle pub lisher a In Publisherl under Pub lish click on Circle b In the Create New Pub lisher window e Select GREEN for Color e Click OK You should now see two cir cles moving on each canvas one red and one green Apply QoS from Profile Choose the profile Default Default Ownership Liveliness Exdusive Strength Lease Duration ms 0 Durability VOLATILE Zi Time based Filter ms V Reliability Content Filter Topic Read method to use Use filter 8 Read TakeQ Cox cme 4 5 Examples Figure 4 2 Publisher and Subscriber Displays for Multiple Instances 4 6 RTI Sha en in File View Publish Subscribe Controls Help Publish 0 Square Circle Triangle Subscribe Square Circle Triangle File View Publish Subscribe Controls Help Pause Publishing Hi i Configuration Reliability t Type Color
30. ers and subscribers are associated with a topic If you create a new topic every time a new flight is detected you would need to create a matching subscriber and pub lisher pair This is obviously not scalable since you can have many different aircraft flight plans Instances give you the ability to scale a topic Unique instances of a topic are defined by unique key values A subscriber of a topic will get all the data sent on all the instances of this topic Take the example of flight track data the key could be the flight ID pilot name or mission code Regardless of how many new flights there are you would only need one subscriber to get the data because the topic is the same In this example the topic is the shape of the object Square Circle or Triangle and the key is its color So different colors of an object give you different instances of the topic For example a red circle is a different instance from a green circle yet they are all instances of the Circle topic At this point you should have two copies of Shapes Demo running which will be referred to as Publisherl and Subscriber1 In this example you will be asked to start additional copies of Shapes Demo Tip If you make a mistake during the following steps and need to delete a single pub lisher or subscriber select the item in the Legend tab and press the Delete key on your keyboard 1 This exercise picks up where the previous one left off So you should have two d
31. esponsi bility for providing data to the network Ownership makes failover simple if the owner fails a backup owner can instantly take over responsibility L Failure notification Connext is designed for the real world In the case of failure e g the violation of a deadline or the termination of service interested applications are immediately notified I Advanced concepts If you are interested in exploring the demo more extensively this document also briefly illustrates additional use cases such as content filtered topics reliability durability and time based filtering L uoygonpoiju Introduction Chapter 2 Background Information 2 1 This section provides an overview of existing middleware communication paradigms including publish subscribe along with basic concepts of Connext If you are already familiar with this information you can go directly to Chapter 3 Installing and Using Shapes Demo Communication Models in Networking Middleware Software applications are becoming increasingly distributed A node in a distributed application must find the right data know where to send it and deliver it to the right place at the right time Simplifying access to this data would enable a whole new class of distributed applications The challenge especially in embedded and real time networks is to quickly find and disseminate information to many nodes Three major middleware communication paradigms have emerged
32. fault setting is an infinite duration meaning the data will never expire If you have multiple publishers for the same instance they should all use the same Lifespan value Other Controls 3 3 6 3 3 7 3 4 3 4 1 Valid settings range from 1 ms to 1 year or INF for infinity the default Using a Content Filtered Topic The Use filter checkbox is only available when creating a subscriber If selected a filter is created for data updates to a topic based on the content of the data Only data that sat isfies the filter will be made available to the subscriber Controlling the Read Method When creating a subscriber you can choose whether it will use read or take LJ With read the default Connext will continue to store the data in the DataReader s receive queue The same data may be read again until it is taken in subsequent take calls Graphically a new sample is shown with a thicker border LI With take Connext will remove the data from the DataReader s receive queue The data returned by Connext is no longer stored by Connext Other Controls The Controls sub panel includes various commands that you can use to control the demo Slow Down Delete All Pause Publishing Hide History Configuration Delete All This command deletes all the publishers and subscribers that have been created in the demo application All objects moving in the application window will disappear and n
33. he canvas The triangle in Subscriber1 should exactly mirror your mouse movements because Publisher2 has a higher strength than Publisher1 5 Click Delete All in the Controls sub panel of each of the three demo windows 4 10 Failure Detection Example 4 4 Failure Detection Example You may want to detect when the publisher or the network is behaving abnormally and the subscriber hasn t seen updates for an instance within a specified period of time The Deadline QoS offers a way to do this Deadline is a contract between the publisher and the subscriber based on the data rate The publisher offers to send data at least once in its specified deadline period and the subscriber requests to receive data within its deadline period If either the subscriber or the publisher misses their deadline an event callback for deadline missed occurs At this point you should have three copies of Shapes Demo running though you will only use two of them for this example The two copies will be referred to as Publisher1 and Subscriber1 Tip If you make a mistake during the following steps and need to delete a single pub lisher or subscriber select the item in the Legend tab and press the Delete key on your keyboard 1 In Publisherl create a cyan square publisher Deadline Create new Publisher Square Color Key Apply QoS from Profile 200 ms Choose the profile a Under Publish click on DefauitD
34. he subscriber s history queue This command has no effect on subscribers that use the take method of accessing data It is only for subscribers that use read It also has no effect on publishers If you set History greater than 1 by default all the packets in the history queue are dis played showing the historical path of the shapes on the subscriber s canvas If History is 1 the default no historical samples appear because there is only room for one sam ple in the queue By default historical samples are shown that is Show History is the default setting and you will see the Hide History command in the Controls panel When you select Show History the samples stay in the reader s queue so you can see the shadow trail of the historical samples up to the number set in the History field Configuration The Configuration command allows you to change the domain ID manage QoS pro files and start stop This is the equivalent of a Reset button short of quitting and restarting the application Other Controls VOD GNE To make any changes with this command z first click Stop make the desired change Choose the domain 5 then click Start If the Choose the profile listbox contains only Default Default this means no XML files have been loaded Choose the profile necs it Default To load an XML QoS Profiles file 1 Click Stop Any publishers subscribers will be deleted when you do this 2 Click Ma
35. how to handle such a situation will be discussed in the next section 6 Click Delete All in the Controls sub panel of each of the three demo windows 4 7 Examples 4 3 4 8 Ownership Example As you saw in the previous example it s possible for multiple publishers to simultane ously send data to the same instance of a topic You may or may not want this behavior For certain types of data such as commands you may want to receive updates from just one publisher at a time in order to be ensure consistency Exclusive ownership is a way to ensure that only one publisher s data for a specific instance can get through to a sub scriber With multiple publishers the one with the highest ownership strength wins At this point you should have three copies of Shapes Demo running which will be referred to as Publisher1 Publisher2 and Subscriber1 Tip If you make a mistake during the following steps and need to delete a single pub lisher or subscriber select the item in the Legend tab and press the Delete key on your keyboard 1 In Publisherl create an orange triangle publisher with Exclusive ownership and Strength 1 a Under Publish click on Triangle b In the Create Publisher window e Select ORANGE for Color New Check Exclusive Ensure Strength is 1 Click OK You should see a floating orange triangle on the canvas We created a publisher with exclusive Color Key Initial
36. implification Complex systems have complex data delivery requirements Connext is perhaps more like a picture in picture in picture super television system with each super TV set capable of displaying dozens or even thousands of simultaneous channels Super IV sets can optionally be broadcast sta tions each can publish hundreds of channels from locally mounted cameras to all other interested sets Any set can add new pictures by subscribing to any channel at any time Each of these sets can also be outfitted with cameras and act as a transmitting station TV sets publish many channels and may add new outgoing channels at any time Each communications channel indeed each publisher subscriber pair can agree on reliability bandwidth and history storage parameters so the pictures may update at different rates and record outgoing streams to accommodate new subscribers 2 5 uonpuoju punoiB opg Z Background Information 2 5 2 6 These super TV sets can also join or leave the network intentionally or not at any time If and when they leave or fail backup TV set transmitters will take over their picture streams so no channels ever go blank That would be quite a system It is only an analogy but we hope this gives you some idea of the enormity of the real time communications challenge It also outlines the power of publish subscribe as you will see Connext provides simple parameters to per mit all these scenarios with a re
37. les from the publisher s history queue In Publisher1 click Pause Publishing In Subscriber1 notice that the samples disappear as they time out Experiment by increasing the Lifespan setting for the publisher The longer the Lifespan the longer it takes for the samples to disappear when you pause publishing More Experiments 4 6 3 Reliability and Durability Example In a dynamic system you may want late joining nodes to get the data that was sent before the nodes connected to the network For example suppose you need to initialize the state of these late joining nodes and don t want to be continually sending the state just in case some node joins late The Durability QoS provides late joining nodes with the ability to get previously sent data 1 Start two copies of Shapes Demo which we will call Publisher1 and Subscriber1 If you are reusing demo windows from the previous section make sure to delete any existing publishers and subscribers under Controls click Delete AIl 2 In Publisher 1 create a circle publisher any color with Transient Local Durabil ity Reliability and History 200 a Under Publish click on Circle b In the Create New Publisher window Use the drop down list box to change Durability to Transient Local e Set History to 200 e Click OK 3 Wait for a bit 4 In Subscriberl create a circle subscriber with Transient Local Durability Reli
38. markably simple and intuitive model Publish Subscribe Example Application An air traffic control system provides a more realistic example application An air traffic control system monitors and directs all flights over an entire continent The data distrib uted in such a system is in the form of aircraft tracks which provides positional infor mation e g course speed etc about an airplane Components of an air traffic control system would include radar systems airplanes and air traffic control centers that pro vide current flight status information through real time displays Managing correct distribution of data in such a system is complex Each radar system can track many different airplanes and each airplane may be tracked by more than one radar system Real time access to this information is needed for displays at air traffic control centers so that air traffic controllers can make informed decisions Air traffic controllers in the north east may only want aircraft track information in their area so only a subset of data needs to be provide to them Based on current local conditions e g air traffic weather etc air traffic controllers may issue flight plan updates back to air planes in order to rout around inclement weather and other airplanes Though airplanes do not need flight plans from all other air planes it would be useful to have information about planes in the immediate vicinity Defining the air traffic control s
39. n paradigms It also provides an overview of Connext and its key concepts LI Chapter 3 Installing and Using Shapes Demo details the features of the demon stration application L1 Chapter 4 Examples jumps right into using the application and playing with examples Feel free to start here if you are familiar with publish subscribe net working L Chapter 5 About RTI describes RTI products and where to seek further informa tion L Appendix A explains how to run from the command line LI Appendix B contains a few troubleshooting hints 1 2 Goals of the Demonstration There is no teacher like experience Playing with this demonstration will give you a first hand introduction to key Connext concepts These include L Anonymous publish subscribe Applications communicating over publish subscribe networks do not need to know the source or destination of the data This loosely coupled design simpli fies or eliminates configuration eases fault tolerance and boosts performance L Dynamic discovery With publish subscribe applications simply ask for the information they need and provide the information they have The middleware does the hard task of finding the information and delivering it where it needs to go There is no or Goals of the Demonstration minimal configuration each node can simply join or leave the network at any time J Failover Connext supports the concept of ownership a publisher can own the r
40. nage QoS 3 In the resulting dialog box f click Add and then browse p to select an XML QoS pro Edit files file V C RTTIUSER QOS PROFILES xml You can use your own file and the one provided with Shapes Demo RTI SHAPES DEMO QOS PROFILES xml is in the same directory where you installed Shapes Demo This file is already included after installation For more information on the con tents of this file see Section 3 3 4 If you specify multiple XML files the Up and Down buttons change the order in which they are loaded If you load files that contain profiles with is default qos true the last profile loaded is used This information is saved in your workspace see Section 3 5 To unload an XML QoS Profiles file 1 Select Configuration then Stop 2 Click Manage QoS 3 In the resulting dialog box clear the checkbox next to the file or select the file and click Remove 3 13 ouJegq eui 6ursn Installing and Using Shapes Demo If the XML QoS Profile file has Errors If you add an XML QoS Profile file that has errors and you click Ok Shapes Demo will try detect the error and will show a popup that indicates with file has been detected to be wrong Once you click OK the Load Unload QoS profile files window will automatically uncheck all the incorrectly formatted files At this point you can either press Ok and proceed without loading those files or edit them by pressing th
41. nformation about profiles see Section 3 3 4 Publish Subscribe Example This example showcases the publish subscribe concept It uses best effort communica tion and shows the decoupling between the publisher and the subscriber i e the pub lisher can send data without knowing where what the subscriber s are and the subscriber can receive data without knowing where what the publisher s are In this example you will be asked to start two copies of Shapes Demo There is no need to con figure a discovery service or provide any a priori information about where the demo applications are being run 4 sejduupx3 p Examples 1 Create a red circle publisher a Start Shapes Demo We will Color Key Apply QoS from Profile refer to this copy of the PURPLE Choose the profile application as Publisher1 Default Default b Under Publish click on TH QoS Values Circle Liveliness c In the Create New Publisher z Strength ms window A Durabili History e Select RED for Color 1 Time based Filter ms Deadline ms e Click OK INF 7 Lifespan ms _ You will see a red circle moving W Reiabilty INF on the Publisher canvas If there were any subscribers the pub sin D bos pes lisher would start sending data the coordinates of the red cir Cm cle 2 Create a subscriber for circles m Create new Subscriber Circle
42. nregister When data is disposed all DataReaders are informed that as far as the DataWriter knows the data instance no longer exists and can be considered not alive When data is unregistered this indicates only that a particular DataWriter no lon ger wants to modify an instance an important distinction if there are multiple DataWriters for the same instance L The Output tab shows statuses events and other information 12 24 44 Creating domain participant on domain 0 12 24 48 DELETE ALL gt All the publishers and subscribers have been successfully removed 12 40 45 Creating domain participant on domain 0 12 40 47 A new generic shape has been created 12 40 47 DataWriterQoS set to use Default Profile Output Shapes Demo s Workspace Shapes Demo uses the concept of a workspace which is an XML file that contains the last settings used by Shapes Demo For example it contains the list of QoS XML profile files loaded through the Load Unload QoS profile files window and whether or not the files should be loaded Another useful piece of information saved in the workspace is the last domain ID as specified by the Configuration window This allows you to start Shapes Demo with well known settings each time If you start Shapes Demo with the domainId option that domain ID setting is not saved in the workspace If your current working directory contains a file named RTI SHAPES DEMO xml it will be used as the works
43. o data will be sent or received NOTE Delete All removes all the entities but it does not destroy the participant The quick reset is to select Configuration Stop Start If you have started multiple copies of Shapes Demo you will need to click Delete All in each copy to delete their respective publishers and subscribers ouJegq ou Buisp Installing and Using Shapes Demo 3 4 2 3 4 3 3 4 4 3 12 Pause Publishing The Pause Publishing command is only effective on publishers It pauses the sending of coordinate data for the shape until you click Resume Publishing When Pause Publish ing is clicked the label changes to Resume Publishing The Pause Resume Publishing commands are also available when you right click an entity if itis a publisher in the Legend tab In this way you can individually pause each single publisher When publishing is paused you will still see published topics colored shapes moving in the publisher demo window but corresponding topics in a subscriber window will stop moving That s because what you see in the publisher window is the data being generated not necessarily sent what you see in the subscriber window is data being received When you pause publishing the subscriber stops receiving updates to the topic that is the shape s coordinates Show Hide History The Show History and Hide History commands tells the demo to start stop drawing the shapes from all the packets that are in t
44. ocess channel is what happens if that process channel doesn t exist etc The application must determine where to get data where to send it and when to perform the transaction In the message passing architecture there is a model of the means to transfer data but no real model of the data itself Publish subscribe adds a data model to messaging Publish subscribe nodes simply publish information they have and subscribe to data they need Messages logically pass directly between the communicating nodes The fundamental communications model implies both discovery i e what data should be sent and delivery i e when and where to send the data This design mirrors time critical information delivery systems in everyday life e g television radio magazines and newspapers Publish subscribe systems are good at distributing large quantities of time critical information quickly even in the presence of unreliable delivery mechanisms Publish subscribe architectures map well to the real time communications challenge Finding the right data is straight forward nodes just declare their interest once and the system delivers it Sending the data at the right time is also natural publishers send data when the data is available Publish subscribe can be efficient because the data flows directly from source to destination without requiring intermediate servers Multi ple sources and destinations are easily defined within the model making redundancy an
45. on File Running Shapes Demo You can run Shapes Demo on a single computer or on multiple workstations connected via Ethernet Both Windows and Linux operating systems are supported You can start multiple copies of the demo on as many computers as you would like By default the demo discovers other demo applications using multicast loopback or shared memory The discovery mechanism is fully configurable 3 ouJegq eui Busy Installing and Using Shapes Demo On Linux systems Enter the following command install directory scripts rtishapesdemo I On Windows systems If you have Connext Messaging you can start Shapes Demo from RTI Connext Launcher s Utilities tab Or from the Windows Start menu navigate to RTI Con next version RTI Connext Messaging version Components RTI Shapes Demo version and select RTI Shapes Demo For details on running from the command line see Appendix A Running from the Command Line When Shapes Demo starts you should see a window like that in Figure 3 1 Figure 3 1 Shapes Demo lInitial View Section 3 3 le F r P Publishing Section 3 4 Hide History z Configuration v Name Type Color Partitions Read Take QoS Settings Reliability Section 3 4 5 Ready on domain 0 3 2 Publish and Subscribe Task Panes 3 3 Publish and Subscribe Task Panes Connext applications publish write and subscribe to read Top Publish i
46. onitorDefault MonitorDemoLibrary SamplesRejectedSc MonitorDemoLibrar y FixedSamplesRejec ues in the selected profile See Setting QoS Values Section 3 3 5 Shapes Demo includes an XML file RTI SHAPES DEMO QOS PROFILES xml which includes these profiles J Default Default This profile means you want to use whichever profile in the XML file is marked as the default with qos profile name x is default qos true In RTI SHAPES DEMO OOS PROFILE xml the default profile is RTI Shapes Lib Shapes Default Profile I RTI Shapes Lib Shapes Default Profile This profile sets the DataWriter s autodispose unregistered instances to false and the DataReader s History depth to keep the last 6 samples L RTI Shapes Lib Batching This profile enables best effort communication in the DataWriter and keeps the last 10 samples It also enables batching with a maximum flush delay of 1 second and allows an unlimited number of bytes to be batched for up to 10 samples RTI Shapes Lib History KeepLast20 This profile sets the DataReader s His tory QoS to keep the last 20 samples 1 See Dispose vs Unregister on page 3 15 3 5 ouJegq eui 6ursn Installing and Using Shapes Demo 3 6 LJ RTI Shapes Lib Ownership Shared This profile sets Ownership to SHARED and Durability to TRANSIENT with direct communication to true for both the DataReader and the DataWriter Both the DataReader s and th
47. pace If the file cannot be found in the current working direc tory Shapes Demo will use the one located in executable dir J if it can be found If the file is still not found on Windows systems Shapes Demo will finally look for the file in My Documents RTI RTI Shapes Demo version You can specify a different workspace file by using the workspaceFile command line option If the file specified after workspaceFile is not found it will be automatically created 1 executable dir gt means the directory two levels up from that of the Shapes Demo executable 3 15 ouJegq eui 6ursf Installing and Using Shapes Demo 3 16 If you do not use workspaceFile and RTI SHAPES DEMO xml is not found any where in the current working directory two levels up the executable directory or My Documents RTI RTI Shapes Demo version on Windows systems Shapes Demo will automatically create a workspace file in executable directory gt on non Windows systems or in My Documents RTI RTI Shapes Demo version on Windows systems the file will be named RTI SHAPES DEMO xml Chapter 4 Examples 4 1 Important Unless otherwise noted these examples assume you are using the default Shapes Demo settings meaning the RTI SHAPES DEMO QOS PROFILES xml file is loaded By default this file tells Connext to load the profile called Shapes Default Profile from the RTI Shapes Lib library and use it as default For more i
48. s sions so a publisher with a wildcard partition will match subscribers with partitions A B C and D A publisher with no partition the default case will not be matched with a subscriber that does have a partition That is no partition is not the same thing as a wild card partition Publish and Subscribe Task Panes 3 3 4 Apply QoS from Profile The drop down listbox allows you to choose a QoS profile that has been pre loaded from an XML file If the listbox contains only Default Default it means you haven t specified any XML files via the Configuration dialog see Section 3 4 4 In this case Default Default will result in all default QoS settings as described in the Connext documentation A profile contains the QoS values that will be used for the objects created by the demo All QoS val ues not specified in the selected profile will use default values noted in the Connext HTML docu mentation Any QoS settings that you make in the Create New Publisher Subscriber dialog take precedence over the val Configuration Choose the domain Choose the profile RTI_Shapes_Lib Shapes_Default_Profile Manage Qos RTI Shapes Lib Batching RTI_Shapes_Lib History_KeepLast_20 ims RTI Shapes Lib Ownership Shared RTI Shapes Lib Ownership Exdusive RTI Shapes Lib Durability Volatile RTI Shapes Lib Durability Transient RTI Shapes Lib Durability Persistent MonitorDemoLibrary M
49. s across a variety of networks Connext Integrator Information Technology IT m m erm a RTI Connext accelerates the integration of operational systems with each other and with enterprise and legacy applications 5 1 About RTI 5 2 The RTI Connext product family consists of LI RTI Connext Integrator Integration infrastructure for connecting disparate Oper ational Technology OT systems and bridging to Information Technology IT LI RTI Connext Messaging Universal messaging software backbone for both OT and IT applications LI RTI Connext DDS Data centric messaging software for advanced distributed systems and applications I RTI Connext Micro Small footprint messaging software for resource constrained and or certifiable applications At the foundation of Connext is a powerful data centric messaging infrastructure that enables scalable integration across an enterprise from the data center to mobile real time and embedded systems With this data centric messaging bus applications exchange information by simply reading and writing data objects shared within a Global Data Space The middleware maintains the data space which captures a system s state Applications are automatically initialized with current data No discrete database or custom state server is required Nor do applications have to maintain their own state and depend on durable messaging to keep it consistent See the RTI Core Libraries and
50. same setting so either check this box for both or leave it unchecked for both Otherwise their QoS are incompatible and the pub lisher and subscriber will not communicate 3 7 ouJeg y Buisp Installing and Using Shapes Demo 3 3 5 2 Table 3 1 3 8 Durobility Durability controls whether the publisher will store the data that it sends so that it can be sent to new subscribers that join the system later The possible settings for this QoS are LJ VOLATILE Default Data samples are not stored TRANSIENT Connext will attempt to store samples in memory The data will sur vive the DataWriter L TRANSIENT LOCAL Connext will attempt to store samples in memory The data will not survive the DataWriter L PERSISTENT Connext will store previously published samples in permanent stor age like a disk The data will survive the DataWriter Which particular samples are stored depends on other QoS such as History Section 3 3 5 6 and ResourceLimits If Durability is selected for a subscriber the subscriber will ask the publisher to send all previously written data All data in the publisher s history queue will be sent to the sub scriber To buffer this temporary high throughput the subscriber should use a History value comparable to the publisher s The publisher and subscriber must use compatible settings as described in Table 3 1 Valid Combinations of Durability Subscriber
51. scribers are requesting current and future samples of that publication so that as new samples are published they are delivered without having to submit another request for data Publish Subscribe Complex Analogy Figure 2 1 Publish Subscribe Example Topic New York Times Topic New York Times 2 4 Sample Publisher Issue for Feb 15 Subscriber Send Receive o md Service mue The publish subscribe model is analogous to publishing magazines or newspapers The Publisher sends samples of a particular Topic to all Subscribers of that Topic With the New York TimesG the Topic would be New York Times The sample consists of the data articles and pictures sent to all Subscribers daily or weekly Connext is the distribution channel all of the planes trucks and people who distribute issues to the Subscribers In this example Quality of Service QoS parameters can be linked to delivery require ments deliver only the Sunday edition the paper must be delivered by 7 00am the paper must be in the mailbox or on the porch etc QoS parameters specify where how and when the data is to be delivered controlling not only transport level delivery prop erties but also application level concepts of fault tolerance ordering and reliability Publish Subscribe Complex Analogy Above we drew an analogy between publish subscribe and a newspaper delivery sys tem That is of course an overs
52. selected then History determines how much previously sent data is sent to late joining subscribers Valid set tings range from 0 to 100 000 000 The default is 1 Deadline For a publisher the Deadline value is the time interval within which the publisher com mits to updating data at least once if not more frequently For a subscriber the Deadline value is the maximum time interval between data updates that the subscriber expects from the publisher If a publisher fails to send a data update within the subscriber s requested Deadline interval the subscriber will get a deadline missed notification Valid settings range from 1 ms to 1 year or INF for infinity the default A subscriber s Deadline value must be greater than or equal to the publisher s A sub scriber s deadline must also be its minimum separation see Time Based Filter Sec tion 3 3 5 3 Lifespan Lifespan is only available when creating a publisher The purpose of the Lifespan QoS is to avoid delivering stale data Each data sample written has an associated expiration time beyond which the data should not be delivered The middleware attaches timestamps to all data sent and received The expiration time of each sample is computed by adding the specified Lifes pan duration to the destination timestamp When you specify a finite Lifespan Connext will compare the current time with those timestamps and drop data when the specified Lifespan expires The de
53. ties of RTI Connext formerly RTI Data Distribution Service As you will see RTI Connext offers flexibility performance and reliability well beyond other networking technologies while addressing the challenge of extremely high performance distributed networking Connext offers flexible and fine grain control over Quality of Ser vice QoS parameters No one application can showcase all the supported QoS parameters Shapes Demo is intended to provide you A pes Demo File View Publish Subscribe Controls Help with an abbreviated introduction to E Connext concepts it covers a small subset of the many QoS parameters A available in Connext Shapes Demo publishes and Delete al subscribes to writes and reads Pause Publishing Hide History colored moving shapes which are Configuration 7 displayed in the demo s window name Type Color Partitions Read Take QoS Settings Reliability t Each copy of Shapes Demo can 3 M Tue simultaneously publish and DefautzDefaut True subscribe to many topics shapes Ready on domain 0 uoygonpoyu L Introduction 1 1 Guide to this Document This document will guide you through the demonstration the middleware and the underlying principles 1 Goals of the Demonstration Section 1 2 below outlines the concepts and goals of this demonstration L Chapter 2 Background Information provides an overview of publish subscribe and other communicatio
54. to meet this need client server message passing and publish subscribe Client server is fundamentally a many to one design that works well for systems with centralized information such as databases transaction processing systems and central file servers However if multiple nodes generate information client server architectures require that all the information be sent to the server for later redistribution to the clients resulting in inefficient client to client communication The central server is a potential bottleneck and single point of failure It also adds an unknown delay and therefore indeterminism to the system because the receiving client does not know when it has a message waiting Message passing architectures work by implementing queues of messages Processes can create queues send messages and service messages that arrive This extends the 2 1 Uuonpuuoju punoiB opg Z Background Information 2 2 many to one client server design to a more distributed topology Message passing allows direct peer to peer connection it is much easier to exchange information between many nodes in the system with a simple messaging design However the mes sage passing architecture does not support a data centric model Applications have to find data indirectly by targeting specific sources e g by process ID or channel or queue name on specific nodes So this architecture doesn t address how applications know where a pr
55. typed data streams identified by names called Topics The Application Programming Interface API offered by Connext complies with the Object Management Group OMG Data Distribution Service DDS standard It is the first comprehensive specification available for publish subscribe data centric designs Connext defines a communications relationship between publishers and subscribers The communications are decoupled in space nodes can be anywhere time delivery may be immediately after publication or later and flow delivery may be reliably made at controlled bandwidth To increase scalability topics may contain multiple indepen dent data channels identified by keys This allows nodes to subscribe to many possi bly thousands of similar data streams with a single subscription When the data arrives the middleware can sort it by the key and deliver it for efficient processing Connext is fundamentally designed to work over unreliable transports such as UDP or wireless networks No facilities require central servers or special nodes Efficient direct peer to peer communications or even multicasting can implement every part of the model Quality of Service Fine control over Quality of Service QoS is perhaps the most important feature of Con next Each publisher subscriber pair can establish independent QoS agreements Thus Connext designs can support extremely complex flexible data flow requirements QoS parameters control
56. ubscriber1 s canvas should freeze Note that now all the sam ples borders have the same thickness this indicates that all of them are historical data In Subscriber1 select the Output tab to see messages notifying the applica tion that the promised deadline of 4000 ms has been missed as seen in Figure 4 5 4 Click Resume Publishing The cyan squares in Subscriber1 s canvas will start moving again mirroring the movement in Publisher1 s canvas 5 Click Delete All in the Controls sub panel of each demo window Failure Detection Example Figure 4 5 Missed Deadline gt Partitions Read Take QoS Settings Reliability Defeut Defaut True 20 27 35 Requested deadline missed for Square 20 27 39 Requested deadline missed for Square Select the Output tab in Subscriber to see the deadline missed messages 4 13 Examples 4 5 4 14 Failover Example In most mission critical systems there are failover mechanisms to handle unexpected behaviors In this exercise we combine the previous two exercises to illustrate hot failover behavior where the primary publisher goes down and the subscriber immedi ately detects the loss and starts taking data from the secondary publisher At this point you should have three copies of Shapes Demo running referred to as Publisher1 Publisher2 and Subscriber1 Tip If you make a mistake during the following steps
57. virtually every aspect of the Connext model and the underlying communications mechanisms Many QoS parameters are implemented as contracts between publishers and subscribers publishers offer and subscribers request levels of service The middleware is responsible for determining if the offer can satisfy the request thereby establishing the communication or indicating an incompatibility error Ensuring that participants meet the level of service contracts guarantees predictable operation More information about some important QoS parameters is presented below 2 3 uonpuuoju punoi opg Z Background Information 2 3 2 4 Deadline Periodic publishers can indicate the speed at which they can publish by offering guaranteed update deadlines By setting a deadline a compliant pub lisher promises to send a new update at a minimum rate Subscribers may then request data at that or any slower rate Reliability Publishers may offer levels of reliability parameterized by the number of past issues they can store for the purpose of retrying transmissions Subscribers may then request differing levels of reliable delivery ranging from fast but unre liable best effort to highly reliable in order delivery This provides per data stream reliability control Strength The middleware can automatically arbitrate between multiple publishers of the same topic with a parameter called strength Subscribers receive from the strongest active pu
58. ystem in terms of publishers subscribers and QoS parameters reveals that Connext is a natural fit to address this data distribution problem Each radar system can be thought of as a publisher that publishes the tracks topic which describes an airplane s positional information Each airplane that the radar sys tem is tracking can be thought of as an instance of the track topic The real time con troller displays are both subscribers that subscriber to the tracks topic and publishers that publish flight plant topic updates back to the specific airplane QoS parameters can be used to manage and control deterministic behaviors and fault tolerance capabili ties of the system Chapter 3 Installing and Using Shapes Demo 3 1 3 2 Installation L On Linux Systems The distribution is packaged in a tar gz file Unpack it as described below You do not need to be logged in as root during installation 1 Create a directory for Shapes Demo 2 Move the downloaded file into your newly created directory 3 Extract the distribution from the uncompressed files For example gt tar xvzf RTI ShapesDemo version tar gz L On Windows Systems Simply double click the downloaded file to run the installer If you run the installer as Administrator and you want to install Shapes Demo for all users they will need to create their own configuration files by selecting Start Programs RTI RTI Shapes Demo version Create Configurati
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