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Knowledge Link: UM Objects

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Transport LBT-IPC

The LBT-IPC transport is an Interprocess Communication (IPC) Ultra Messaging (UM) transport that allows sources to publish topic messages to a shared memory area managed as a static ring buffer from which receivers can read topic messages. For a thorough introduction to the LBT-IPC transport, see the Ultra Messaging Guide > "UM Objects" > "Transport Objects" > "Transport LBT-IPC".
The following sections provide in-depth articles on the most common decisions and issues that architects, developers, and front-line support face when implementing and running solutions using the LBT-IPC transport.

Topic resolution

The LBT-IPC transport provides a shared memory area for processes to move and copy data between themselves, and so topic resolution must still take place so that sources can advertise the location of the shared memory area and the topics available. However, these topic resolution messages should not leave the host machine, for both, efficiency reasons and, so that processes on other machines do not incorrectly try to join the advertised transports.  




142392 How does Topic Resolution work when using the LBT-IPC transport? How to stop topic resolution traffic from IPC sources from unnecessarily leaving the machine
118427 ERROR: "LOG Level 5: LBT-IPC: failed to open shared memory (2)" with LBT-IPC Transport The most common reason for this error is that a receiver is trying to access shared memory on another machine

LBT-IPC Resource management

When the LBT-IPC based applications shutdown cleanly, all memory resources are freed correctly to be reused by other applications. However, if an application is terminated or crashes, these resources will not be reclaimed automatically. In this case, either the UM Resource Manager or OS specific commands must be used to free the locked resources.




80201 Managing LBT-IPC Host Resources Comprehensive guide to how the host resources are used by LBT-IPC applications and how to use the resource manager and the OS to ensure the resources are released
149904 FAQ: Why is the following error message reported: "Core-5688-633: LBTIPC: error opening resource registry (13) Core-5688-593: IPC Error: Creating Receiver Signal Semaphore"? The most likely causes of this message are permissioning or memory exhaustion. Check the permissioning by looking at the Hardware/OS specific recommendations, and the IPC resources articles in this table.  

Hardware/OS specific recommendations 

Using IPC means creating a shared memory area which can be accessed by multiple processes on the machine. In particular on machines running the Windows OS, it is important to make sure that applications are run with the correct permissions so that they can create and view the shared memory areas.  




80257 Windows 7 privileges required for LBT-IPC How to make sure your programs are definitely being run as Administrator in Windows 7
80260 FAQ: How to tune LBT-IPC for Intel Nehalem processors? Tweaking the BIOS and OS settings to improve the processor performance when using IPC
80270 Why do I receive error message "lbm_src_topic_alloc: LBT-IPC: failed to allocate shared memory (5)"? Windows specific recommendations for permissioning and running LBT-IPC applications (all versions prior to Windows 7)

UM Compatibility

This section looks at how applications running on the LBT-IPC transport can interact with the other UM daemons and resources. Specifically, how a host running LBT-IPC can interact with other UM domains running on other transports.




80214 FAQ: Can the Gateway be configured for IPC transport? How to combine IPC and the Gateway to create an architecture spanning multiple machines and domains
142216 FAQ: Why does message latency increase when there are multiple receivers sharing topic subscriptions on the same machine?​ How to architect a low-latency solution when there are multiple receivers on a single machine that are interested in the same topic. ​

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Last Modified Date: 7/17/2013 5:05 PM ID: 150675
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