LBM Key Concepts

Where ever possible, we leverage the intelligence in the network to group traffic, identify available services and reduce the loads on individual receivers. We are focused on the high speed, low-latency delivery of very large amounts of message traffic. With this in mind, we have reduced multi-level architectures wherever possible. In addition, we want the sending application to be able to control data flow as well as protocol selection. If the sending application does not want to define this, the messaging layer can pick the most efficient transport based on a set of rules built into the messaging layer, or the system administrator can configure it.

A High Performance, Flexible Topic Design

  • LBM’s publish/subscribe model is a topic-centered design that allows multiple senders to publish to a topic and multiple receivers to subscribe to the same topic.
  • Completely symmetrical data flow: Any machine can be a sender, a receiver or both. The protocol scales across WAN boundaries and generates minimal recovery traffic.
  • Automatic topic resolution. The LBM messaging layer ensures that all messages sent to a given topic are distributed to all receivers listening to that topic. Subscribers receive all the information needed to receive the data (address, port, etc). All message routing is done by the network hardware.
  • LBM offers wildcard receivers so a receiving application can specify a pattern that LBM uses to match multiple topics.
  • LBM also offers a request/response messaging model. Requests sent by initializing receivers can prevent senders from publishing to unsubscribed topics, reducing needless message traffic.
  • LBM provides a late join feature that allows a new receiver to join a group of other receivers already listening to a source and receive any messages that were sent before it joined the group. Retransmission options are application configurable.

Multiple Data Transports

  • Support for:
    • Reliable IP Multicast
    • TCP/IP
    • Latency Bounded TCP/IP
    • Reliable UDP Unicast
  • Multi-layer group addressing constructs. This allows traffic to be divided via multicast groups as well as by topics. It also allows as many topics to be supported by the messaging layer as needed by the applications. The management and support of these topics is shared through the network, with no central server needed.
  • Flexible Delivery Ordering—Receivers can specify “in order” or “arrival order” for topic messages. Messages delivered “in order” arrive in sequence number order to the application. With “arrival-order” delivery, messages arrive at the application as they are received by the transport session.
  • Support for Latency bounded TCP message delivery. LBM allows the sender to decide if it wants to wait for slower TCP receivers. For more information on latency issues with TCP, please see Topics in High Performance Messaging.

More Flexibility, More Control...

  • An LBM event queue is essentially a managed data and control buffer from which LBM delivers events (including received messages) to your application by means of application callbacks. Event queue options are application configurable and by using multiple application threads to dispatch events or multiple event queues, you can take advantage of parallel processing on multi-processor hardware.
  • Application configurable delivery guarantees allow the sending applications to decide what should happen to slow receivers and how packet recovery should be handled.
  • Ability to use rate controls to limit both recovery traffic and sending traffic. This can provide network stability in the case of unexpectedly high peak data flows that could push a network without rate control into a “NAK implosions” or “broadcast storm” condition.
  • Detailed monitoring and traffic statistics are provided. Using the LBM API, applications can either be monitored internally, or statistics can be aggregated into a central monitoring location. LBM statistics monitoring can also be integrated into the customer's existing monitoring framework with 29West’s SNMP Agent.

The combination of flexible topic design, multiple transport models and efficient tuning mechanisms allows the 29West messaging layer to provide the approach that bests suits your application parameters and network capabilities. By providing extensive remote configuration support and management capabilities, we have reduced the time it takes to update an application and made it easy to scale LAN/WAN and other network boundaries.