LLC - The Low-Level Communicator

The LLC

The Low-Level Communicator (LLC) coordinates and intelligently routes all communication, for example messages, between applications and the switch. It is the only module that communicates directly with the switch over an Ethernet connection, and that can distribute and collect messages to and from all the application modules.

The LLC coordinates many low-level communication tasks that otherwise would be the application’s responsibility, such as:

• Message formatting, queuing, sequencing and acknowledgment

• Calculating checksums

• Handling special characters

• Message and error logging

• Intelligent channel allocation

• Socket management

• Connections to multiple switches

Because the LLC serves as a layer above the platform, it can handle multiple application modules running on any machine in the network. Messages can be routed intelligently among all of the application modules. When a message arrives on a channel, LLC routes that message to whatever application is responsible for that channel. By using this mechanism, two independent applications can share a single Excel platform. Also, you can structure an application system to contain multiple application modules, to provide redundancy, load sharing, and separation of functionality.