ATM and FDDI Networks: Advanced Data Transmission Solutions

Asynchronous Transfer Mode (ATM) Networks

Integrating Multimedia Services with ATM VPN

The integration of voice and image services within Asynchronous Transfer Mode (ATM) creates a Multimedia Virtual Private Network (VPN). This innovative approach allows services previously provided on separate networks to be consolidated into a single, unified network.

ATM VPNs are based on the concept of a Virtual Private Network, offering resources dedicated exclusively to the client. This is achieved through a shared network infrastructure and a single access point to the network. Integration is facilitated by deploying an integration device at the customer's premises.

ATM Integration Device Capabilities

The integration device can consolidate data, voice, and image traffic onto a single access line. This multiplexing combines all types of ATM cell traffic for network delivery. Similarly, upon receiving a packet, the device can differentiate traffic types and deliver them to their respective destinations. Furthermore, this device is configured to prioritize traffic sensitive to delays, such as speech and images, over less sensitive traffic like text or general data.

ATM Protocol: An Evolution in Packet Switching

The ATM protocol, utilized in this service, can be considered an evolution of Frame Relay. The key difference is that instead of using variable-length packets, ATM employs fixed-length packets, known as "cells." Each cell is 53 bytes long, with 48 bytes for information and 5 bytes for the header.

ATM introduces minimal additional information for error handling, relying on the robustness of the network environment and the destination's ability to detect errors. Moreover, the use of fixed-length packets significantly reduces packet processing overhead, contributing to higher network efficiency.

Fiber Distributed Data Interface (FDDI) Networks

Understanding the FDDI Token Ring

An FDDI ring is essentially a fiber optic token ring network. The "token ring" refers to the method by which a node connected to the FDDI ring accesses the network. The ring topology is physically implemented using optical fiber.

Nodes cannot transmit data until they acquire the token. This token is a special frame that circulates the ring, indicating when a node is permitted to transmit. When a node detects this token and has data to transmit, it captures the token by removing it from the ring. After transmitting its data, the node releases the token, either when its transmission is complete or when its allocated time of possession expires.

Advantages of FDDI Fiber Optic Networks

• Enhanced Security

  Optical fiber does not emit electrical signals, making it highly resistant to interception and eavesdropping.

• Superior Reliability

  Fiber optic cabling is immune to electrical interference, ensuring consistent and reliable data transmission.

• High Speed Performance

  Optical fiber offers significantly higher performance potential compared to traditional copper cabling, supporting high-bandwidth applications.