# Aztek protocol stacks

Aztek protocol software implements the upper layers of the V5.2 and GR303 protocols. Aztek provides the following products that can be obtained separately:

- Access303 (RDT side of the GR303 protocol) and Exchange303 (IDT side of the GR303 protocol) software

- AV5 (V5.2 protocol) software

## Access303 and Exchange303 protocol software

Aztek Access303 and Exchange303 software support the remote digital terminal (RDT) and integrated digital terminal (IDT) sides of a GR303 interface, as defined in GR303-CORE and GR303-IMD. This software includes the time slot management channel (TMC) and link access procedures for the D-channel (LAPD) protocols.

Access303 and Exchange303 also provide embedded operations channel (EOC) functions of a convergence layer, a remote operations service element (ROSE) layer, a common management interface service layer (CMISE), and path protection functionality. Access303 and Exchange303 also include the AIM-303 (aim303), an integration tool for the protocol software.

Access303 and Exchange303 are based on a layered software architecture. Layer 2 supports the LAPD protocol. When communicating between an RDT and an IDT, LAPD sends messages to, or receives messages from, the physical layer (Layer 1) provided by the application. When communicating with the rest of the RDT or IDT application, LAPD exchanges messages with the upper layer.

Access303 meets GR303-CORE and GR303-IMD specifications and the GR303 interface specifications for switch vendors. Because Access303 and Exchange303 are independent from the underlying network architecture, applications that integrate with the Access303 and Exchange303 protocol stacks can be based on digital loop carrier (DLC), hybrid fiber coax (HFC), wireless local loop (WLL), voice over the internet protocol (VOIP), or any other access network architecture.

The Access303 and Exchange303 products are provided as source code that can be ported to a variety of hardware and operating system platforms for which an ANSI C compiler is available. The Access303 and Exchange303 stacks can be built in either library or executable form.

## AV5 protocol software

Aztek AV5 software implements the access network (AN) end of an ETSI V5 protocol. AV5 provides five Layer 3 protocols, one Layer 2 protocol, and layer management. Supported Layer 3 protocols include:

Protocol | Description
PSTN | Supports signaling for analog ports.
BCC | Supports dynamic timeslot assignment.
Control | Supports synchronized application of provisioning data, port blocking, and restart.
Link control | Provides link blocking and coordination of link numbering.
Protection switching | Supports standby protection of the signaling channels.

AV5 supports the Layer 2 protocol LAPV5, which is a LAPD-like protocol specifically adapted for V5 interfaces. AV5 also provides frame relay capabilities for ISDN D-channels at Layer 2. The layer management entity supports a set of management capabilities including data link management, E1 link management, protection management, and the provisioned database capabilities. These management features allow higher level management of the Layer 3 protocol entities, and thus provide for simplified system management.

AV5 is a complete implementation of the V5.1 and V5.2 protocol with additional features and tools that has been proven compliant with industry standards through testing with the ETSI abstract test suite (ATS).

AV5 interacts with an AN system in the following areas:

- An RTOS abstraction interface for which Aztek provides sample code.

- A PSTN nationalization sample task.

- APIs for connections through a TSI.

- APIs with Layer 1 and Layer 1 management functions.

- APIs with system management.

The AV5 product is provided as source code that can be ported to a variety of hardware and operating system platforms for which an ANSI C compiler is available. The AV5 stack can be built as either a library or an executable.

For detailed information about Aztek software components, refer to the Aztek documentation.