Principles of Telecommunication Routing and Traffic Systems

Criteria for Routing Decisions

Routing decisions are made by the system to manage traffic according to the network infrastructure. There are three primary criteria:

• First Criterion: If a direct link exists with the central objective, the call is routed to that section, with overflow traffic directed to the final section.
• Second Criterion: Used only if the first criterion cannot be applied. If there is no direct link between the start and end, but a connection exists between the beginning and a higher hierarchical rank, traffic is routed through the shortest path, with overflow directed to the final section.
• Third Criterion: Used only if neither the first nor second criteria apply. Calls are directed to the final section (hierarchical network); overflow traffic is lost if it fails to reach the final destination.

Stages of Concentration and Distribution

The system operates through specific stages:

• Concentration Stage: Economizes the number of circuits used. It does not allow all terminals to communicate simultaneously.
• Distribution Stage: Facilitates accessibility among organs and connection circuits.
• Network Expansion Stage: Connects all terminals to each other, even when the number of system circuits is lower than the number of connected terminals.

MIC Digital Transmission

The MIC (Pulse Code Modulation) system creates a digital 125-microsecond frame divided into 32 time intervals, known as time channels, each with a duration of approximately 3.9 microseconds. Each range is divided into 8 bits with a duration of 488ns each. This system achieves a specific transmission speed.

Telephone Traffic Concepts

Telephone traffic is a concept tied to the utilization of parts within a telephone system. A telephone circuit is considered to be carrying traffic when it is occupied. A phone is considered to have traffic when it is picked up; it has no traffic when it is idle. This concept is applicable to any central body (circuits, links, etc.) or within the circuits of a telephone network. Telephone traffic is measurable in terms of employment time, depending on the number of communications and their duration.