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Chapter 1

Digital to Loop Carrier Protocols

1.1 Digital Loop Carrier Protocol Support

: 1.1.1 Overview of DLCP
: 1.1.2 Platform Support for DLCP: Components

1.2 Access303 and Exchange303 GR-303 Support

1.3 Access AV5 V5.2 Protocol Support

1.4 Developing IDT, RDT, and AN Applications

: 1.4.1 Building Access303, Exchange303, or AV5 Libraries
: 1.4.2 Using the AIM Utilities
: 1.4.3 Using nms303tool and nmsv5tool

1.5 Frequently Used Acronyms

1.1 Digital Loop Carrier Protocol Support

Digital Loop Carrier Protocols (DLCPs) are protocols that outline digital mechanisms for bringing a wide range of services to users through twisted-pair copper phone lines. Remote digital terminals use DLCP protocols to communicate with Central Office (CO) switches. By utilizing DLCP protocols, new network access gateways can easily interface with CO switches as well, allowing service providers to implement new services with minimal impact to the installed network infrastructure.
The DLC protocols GR-303 and V5.2 enable carriers to use location-specific remote concentrators in the local loop and while increasing the reach of individual switches in the network. In these scenarios, gateways must interoperate with various types of network equipment while enabling carriers to provide new services. The use of proven protocol stacks enables carriers to deploy innovative services without performing extensive testing on each switch in the network.

1.1.1 Overview of DLCP

Platform Support for DLCP provides tools for developing applications that use DLCP protocol stacks running on NMS telecommunications interface platforms. For example, network equipment providers can develop access gateway solutions that connect voice over cable networks to existing PSTNs to make new services accessible through legacy networks. Using the GR-303 and V5.2 protocols allows carriers to quickly integrate such gateways into their networks.
Platform Support for DLCP also provides tools that equipment providers can use to create solutions for entering new markets. For example developers can use Platform Support for DLCP tools to develop access gateways that transport voice over fixed wireless networks and provide new services to subscribers in remote areas.
Figure 1 provides an overview of the Platform Support for DLCP development environment: Figure 1. Platform Support for DLCP Overview

1.1.2 Platform Support for DLCP: Components

Platform Support for DLCP consists of the following components: Component Description NMS GR303 library A function library that enables remote digital terminal (RDT) or integrated digital terminal (IDT) applications to perform GR-303 protocol stack operations through a simplified API. NMS V5 library A function library that enables access network (AN) applications to perform V5.2 protocol stack operations through a simplified API. nmstool303 and nmstoolv5 demonstration programs Programs (provided as compileable source code) that allow developers to test various functions from the NMS GR303 and NMS V5 libraries and to test the system integration with the Aztek Access303, Exchange303, or AV5 protocols stacks. Sample configuration files Sample NMS OAM (Operations, Administration, and Maintenance) configuration files for configuring CG boards for use with the NMS GR303 and NMS V5 libraries.
Development systems that use Platform Support for DLCP must have the following additional hardware and software: One or more CG 6000 or CG 6000C boards Windows 2000 or SPARC Solaris 8 operating system NACD 2001-1 software Aztek Access303, Exchange303 (GR-303) or AV5 (V5.2) protocol stack software C++ development environment for Windows 2000 or SPARC Solaris 8
For information about installing Platform Support for DLCP software, refer to the Platform Support for DLCP Installation Booklet.

Component	Description
NMS GR303 library	A function library that enables remote digital terminal (RDT) or integrated digital terminal (IDT) applications to perform GR-303 protocol stack operations through a simplified API.
NMS V5 library	A function library that enables access network (AN) applications to perform V5.2 protocol stack operations through a simplified API.
`nmstool303` and `nmstoolv5` demonstration programs	Programs (provided as compileable source code) that allow developers to test various functions from the NMS GR303 and NMS V5 libraries and to test the system integration with the Aztek Access303, Exchange303, or AV5 protocols stacks.
Sample configuration files	Sample NMS OAM (Operations, Administration, and Maintenance) configuration files for configuring CG boards for use with the NMS GR303 and NMS V5 libraries.

1.2 Access303 and Exchange303 GR-303 Support

GR-303 defines a generic set of requirements for Integrated Access Systems. This set of requirements specifies an open interface that provides "mix and match" flexibility between the Local Digital Switches (LDSs) and RDTs, and between RDTs and element management systems.
GR-303 requirements were defined by Telcordia to eliminate the proprietary interfaces that were common among access systems. GR-303 promotes increased network architecture flexibility by providing a consistent approach to deploying access technologies in the network. GR-303 interfaces reduce the cost of deployment by supporting a flexible service concentration.
In the GR-303 scheme, DS1 facilities connecting to the digital switch are assigned and managed through a Timeslot Management Channel (TMC), while remote operations functions are supported over an Embedded Operations Channel (EOC). A Data Link Processor (DLP) common control module terminates the GR-303 EOC and TMC interfaces from the switch.
Aztek's GR-303 protocol stack (Access303 and Exchange303) software enables gateways and remote digital terminals in North America to interface to the Central Office. Access303 and Exchange303 provide a complete TMC and EOC (timeslot management channels and embedded operations channels) implementation of the GR-303 specification for both the IDT and RDT side of the interface.

1.3 Access AV5 V5.2 Protocol Support

Access Network (AN) applications can use a V5.2 protocol stack to connect to Local Exchanges (LE) applications. In addition, applications can use the V5.2 protocol for the following access methods: Analog telephone access Other digital or analog access for semi-permanent connections without associated out of band signalling information
The V5.2 protocol can use up to sixteen 2048 kbps links. For analog access on the LE side, the application converts signalling from PSTN ports into a functional part of the V5.2 protocol for signalling to the AN side. For ISDN applications, a control protocol within the V5.2 protocol defines a method for exchanging individual functions and messages required for coordinating call control procedures on the Local Exchange.
The V5.2 protocol includes the following features for supporting increased traffic and dynamic link allocation: A bearer channel connection protocol that the Local Exchange can use to establish and tear down bearer connections (identified by the signaling information) on demand. A link control protocol for the multi-link management, that allows applications to control link identification, link blocking, and link failure conditions. A protection protocol (operated on two separate data links for security reasons) for managing communication channel switching in the event of link failures.
Aztek AV5 software is designed to meet the requirements of access network equipment and supports the V5.1, V5.2, 1st Edition and 2nd Edition ETSI standards.

1.4 Developing IDT, RDT, and AN Applications

Use Platform Support for DLCP software to develop IDT, RDT or AN applications by performing the following steps: Step Description For more information, refer to... 1. Install Platform Support for DLCP software on a system that meets the minimum system requirements. Platform Support for DLCP installation booklet. 2. Install Aztek's Access303, Exchange303, or AV5 protocol stack software. Aztek Access303, Exchange303, or AV5 documentation. 3. Build the Access303, Exchange303, or AV5 protocol stack as a library. Access303, Exchange303, or AV5 integration guides. 4. Build the Aztek aim303 or aimv5 utility as an executable. Access303, Exchange303, or AV5 integration guides, Aztek Integration Menu AIM user guides. 5. Build the nms303tool or nmsv5tool demonstration program as an executable. Chapter 9 of this manual. 6. Create a mapping for board, trunk, and channel locations between Platform Support for DLCP libraries (NMS GR303 or NMS V5) and Aztek protocol stack libraries (Access303, Exchange303, or AV5). Chapter 9 of this manual. 7. Configure the CG hardware (through NMS OAM system configuration and board keyword files) and boot the boards. Chapter 3 of this manual. 8. Connect CG boards to the peer (RDT), IDT, or LE side of the interface. CG board installation and developer's manual. 9. Start the nms303tool or nmsv5tool demonstration program. Chapter 9 of this manual. 10. Start the aim303 or aimv5 utility. Aztek Integration Menu AIM user guides and Chapter 7 of this manual 11. Use options from the Platform Support for DLCP demonstration programs (nms303tool or nmsv5tool) to execute functions at the physical layer of the GR-303 or V5.2 protocol stack, and use options from the Aztek AIM utilities (aim303 or aimv5) to execute functions at the upper layer of the GR-303 or V5.2 protocol stack. Chapter 9 of this manual, the Aztek Integration Menu AIM User Guides.
You can create RDT, IDT, or AN applications by adding functionality to the nms303tool or nmsv5tool demonstration programs, or by creating your own applications.

Step	Description	For more information, refer to...
1.	Install Platform Support for DLCP software on a system that meets the minimum system requirements.	Platform Support for DLCP installation booklet.
2.	Install Aztek's Access303, Exchange303, or AV5 protocol stack software.	Aztek Access303, Exchange303, or AV5 documentation.
3.	Build the Access303, Exchange303, or AV5 protocol stack as a library.	Access303, Exchange303, or AV5 integration guides.
4.	Build the Aztek `aim303` or `aimv5` utility as an executable.	Access303, Exchange303, or AV5 integration guides, Aztek Integration Menu AIM user guides.
5.	Build the `nms303tool` or `nmsv5tool` demonstration program as an executable.	Chapter 9 of this manual.
6.	Create a mapping for board, trunk, and channel locations between Platform Support for DLCP libraries (NMS GR303 or NMS V5) and Aztek protocol stack libraries (Access303, Exchange303, or AV5).	Chapter 9 of this manual.
7.	Configure the CG hardware (through NMS OAM system configuration and board keyword files) and boot the boards.	Chapter 3 of this manual.
8.	Connect CG boards to the peer (RDT), IDT, or LE side of the interface.	CG board installation and developer's manual.
9.	Start the `nms303tool` or `nmsv5tool` demonstration program.	Chapter 9 of this manual.
10.	Start the `aim303` or `aimv5` utility.	Aztek Integration Menu AIM user guides and Chapter 7 of this manual
11.	Use options from the Platform Support for DLCP demonstration programs (`nms303tool` or `nmsv5tool`) to execute functions at the physical layer of the GR-303 or V5.2 protocol stack, and use options from the Aztek AIM utilities (`aim303` or `aimv5`) to execute functions at the upper layer of the GR-303 or V5.2 protocol stack.	Chapter 9 of this manual, the Aztek Integration Menu AIM User Guides.

1.4.1 Building Access303, Exchange303, or AV5 Libraries

Several architectural approaches are available for designing the RDT, IDT, or AN applications. This manual describes scenarios where the Access303, Exchange303, or AV5 software are built as libraries and then linked to applications. You do not need to make changes to the Access303, Exchange303, or AV5 source files to perform basic system integration.
Refer to the Access303, Exchange303, or AV5 integration guide for more information about building Aztek protocol stack libraries.

1.4.2 Using the AIM Utilities

Aztek Integration Menu (AIM) utilities, aim303 and aimv5, are installed with Access303, Exchange303, and AV5 software. These utilities allow you to test and integrate Access303, Exchange303, and AV5 functions into the RDT or AN applications.
Each AIM utility is an interactive console application that performs a variety of functions, such as calling API functions, configuring task and message tracing, and displaying status information. Each AIM utility operates as a stand-alone process that communicates with a dedicated task on the Aztek protocol stack to pass commands to the stack.
The AIM utilities are provided as source code. You must compile the applications before using them. For more information about the aim303 and aimv5 utilities, refer to the Aztek Integration Menu AIM-303 User Guide or Aztek Integration Menu AIM-V5 User Guide.

1.4.3 Using nms303tool and nmsv5tool

Use the nms303tool and nmsv5tool demonstration programs provide a way of verifying that the Platform Support for DLCP software is installed and operating correctly. Use these utilities to: Test individual or combinations of the NMS GR303 or NMS V5 library functions. Expose working examples of GR303 functions. Provide a working software example of an integrated application that uses the Aztek and Platform Support for DLCP libraries.
nms303tool and nmsv5tool are menu-driven interactive programs. Enter commands to exercise different integration options while simultaneously running the Access303, Exchange303, or AV5 protocol stacks and the aim303 or aimv5 utilities. nms303tool and nmsv5tool are provided as source code. You must compile the applications before using them.

1.5 Frequently Used Acronyms

The following table lists acronyms that are used frequently in this manual Acronym Description AN Access Network. The portion of a public switched network that connects access nodes to individual subscribers. More simply, it is the last link in a network between the customer premises and the first point of connection to the network infrastructure-a point of presence (PoP) or central office (CO). BCC Bearer Channel Connection protocol. A protocol that allows the Local Exchange (LE) to instruct the Access Network (AN) to allocate bearer channels on demand, either singly or in multiple instances. DLCP Digital Loop Carrier Protocols. Protocols that make use of digital techniques to bring a wide variety of services to users through twisted-pair copper phone lines. DS1 Digital Signal 1. A serial digital signal transmission format in which 24 duplex voice circuits are time division multiplexed into one 1.544 Mbps T1 digital circuit. Also referred to as T1. EOC Embedded Operations Channel. A channel provided on telecommunications facilities to support remote management operations such as provisioning, maintenance, protection switching, and alarm surveillance. ETSI European Telecommunications Standards Institute. IDT Integrated Digital Terminal. A virtual network element that represents the operation of a protocol (for example GR-303) within a switch. HDLC High-level Data Link Control. A link layer protocol for point-to-point and multiple-port communications. LAPD Link Access Procedures for the D-channel. A protocol for communication at the data link layer. LAPV5 Link Access Procedures for the V5.2 protocol. A sub-layer of the V5.2 link layer that provides reliable, end-to-end communication paths between the AN and LE for exchanging PSTN signaling information and other V5.2 control information. LDS Local Digital Switch. LE Local Exchange. Exchange in which subscribers' lines terminate, having access to other exchanges and to national trunk networks. Also, central office (CO). A local exchange carrier (LEC) is a common carrier that operates local exchanges in a given geographical area. PSTN Public Switched Telephone Network. The domestic telecommunications network commonly accessed by ordinary telephones, PBX trunks and data communications facilities. RDT Remote Digital Terminal. The digital loop carrier multiplexer at the end of the digital loop carrier that is closest to the network interface. According to the GR-303 protocol, an RDT provides the side of the interface devoted to subscribers. When communicating with the PSTN, a media gateway performs functions of the RDT. TMC Timeslot Management Channel. A channel used for timeslot allocation and deallocation and for assigning and managing facilities connected to an LDS.

Acronym	Description
AN	Access Network. The portion of a public switched network that connects access nodes to individual subscribers. More simply, it is the last link in a network between the customer premises and the first point of connection to the network infrastructure-a point of presence (PoP) or central office (CO).
BCC	Bearer Channel Connection protocol. A protocol that allows the Local Exchange (LE) to instruct the Access Network (AN) to allocate bearer channels on demand, either singly or in multiple instances.
DLCP	Digital Loop Carrier Protocols. Protocols that make use of digital techniques to bring a wide variety of services to users through twisted-pair copper phone lines.
DS1	Digital Signal 1. A serial digital signal transmission format in which 24 duplex voice circuits are time division multiplexed into one 1.544 Mbps T1 digital circuit. Also referred to as T1.
EOC	Embedded Operations Channel. A channel provided on telecommunications facilities to support remote management operations such as provisioning, maintenance, protection switching, and alarm surveillance.
ETSI	European Telecommunications Standards Institute.
IDT	Integrated Digital Terminal. A virtual network element that represents the operation of a protocol (for example GR-303) within a switch.
HDLC	High-level Data Link Control. A link layer protocol for point-to-point and multiple-port communications.
LAPD	Link Access Procedures for the D-channel. A protocol for communication at the data link layer.
LAPV5	Link Access Procedures for the V5.2 protocol. A sub-layer of the V5.2 link layer that provides reliable, end-to-end communication paths between the AN and LE for exchanging PSTN signaling information and other V5.2 control information.
LDS	Local Digital Switch.
LE	Local Exchange. Exchange in which subscribers' lines terminate, having access to other exchanges and to national trunk networks. Also, central office (CO). A local exchange carrier (LEC) is a common carrier that operates local exchanges in a given geographical area.
PSTN	Public Switched Telephone Network. The domestic telecommunications network commonly accessed by ordinary telephones, PBX trunks and data communications facilities.
RDT	Remote Digital Terminal. The digital loop carrier multiplexer at the end of the digital loop carrier that is closest to the network interface. According to the GR-303 protocol, an RDT provides the side of the interface devoted to subscribers. When communicating with the PSTN, a media gateway performs functions of the RDT.
TMC	Timeslot Management Channel. A channel used for timeslot allocation and deallocation and for assigning and managing facilities connected to an LDS.

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