Legacy Protocol Stack Drivers

Description - Extensions to the kernel

Purpose - Implement legacy protocols (X.25, SNA, Link Layer, Bisync, etc.).

Other Names - Protocol stacks, legacy protocols, STREAMS modules, protocol modules

Usage Benefits - Gcom® legacy protocol stack drivers:

• Have been used in mission-critical environments for over 25 years.
• Are used in thousands of locations across the globe.
• Have been fine-tuned over the decades to fit real-world situations.
• Can help developers build more flexible communication products.
• Improve administrators' ability to maintain and troubleshoot communication products - Gcom's legacy protocol stack drivers ship with a full suite of analysis utilities, can perform tracing, provide configurable error reporting, and can generate custom signals. The utilities implement a rich vocabulary of options so that administrators can use them to monitor statistics as well as troubleshoot protocol-level problems.

More on Relationships

Gcom_config - Gcom_config builds and configures the legacy protocol stack drivers.

Gcom_monitor - In addition to building the Gcom STREAMS environment in which the legacy protocol stack drivers operate, Gcom_monitor monitors the drivers for event notifications and logs the events.

Gcom_ssd - Gcom_ssd converts legacy protocols to/from the SyncSockets® protocol using the SyncSockets API and legacy APIs.

A single Gcom_ssd, which can handle a virtually unlimited number of connections, can communicate with multiple legacy protocol stack drivers because the decision as to whether a particular legacy protocol connection is, for example, SNA or X.25, is made on a per-connection basis.

System log file - The legacy protocol stack drivers log CDI-, DLPI- and NPI-level processing events.

Gcom_monitor log file - The Gcom_monitor log file logs initialization events for each legacy protocol stack driver.

Custom application - If the custom application interacts with Gcom_ssd via the SyncSockets API, the custom application manages the state of the legacy protocols by tracking the status of the SyncSockets Finite State Machine (which detects illegal operation sequences as well as returns simple codes that tell the custom application what to do next).

For more Gcom information...

• Bisync Protocol Specification
• FAQs
• Gcom Management Console User Guide
• Gcom Protocol Appliance Guide
• Link Layer Protocol Specification
• NPI M-bit and D-bit Processing White Paper
• SNA Protocol Specification
• STREAMS
• Why STREAMS?
• X.25 Protocol Specification
• X.25 SVCs and PVCs White Paper

For more general information...

• High-Level Data Link Control
• Introduction to SNA
• ISDN Overview (LAPD)
• LAPB
• OSI Model
• Pioneering Protocols (Bisync)
• Seven Layer Model
• Synchronous Data Link Control (SDLC) Overview
• X.25
• X.25 Packet Layer Protocol (PLP) Overview