Tag Archives: networks

There are two primary types of data transfer protocols: relaying and multiplexing protocols and error- and flow-control protocols. The main difference between these types is their scope and the presence of feedback mechanisms. Relaying protocols typically operate without feedback, making them less affected by inconsistent state, whereas error-control protocols involve feedback mechanisms, ensuring reliability by addressing errors introduced during data transmission.

The operation of communication protocols is typically divided into three distinct phases: Enrollment, Establishment (or Synchronization), and Data Transfer. Each phase plays a crucial role in ensuring that communication between systems or applications is successful.

The concepts of mechanism and policy are well known in operating systems and communication protocols. In protocols, mechanisms are the static, unchangeable functions or procedures that are defined by a protocol. Policies, on the other hand, dictate how and when a mechanism should be used.

The concept of a service boundary is fundamental in communication protocols. It represents the dividing line between different protocol layers, specifically between a protocol machine (PM) and the PM or application it serves, the (N+1)-PM. This boundary is where data is exchanged.

There are four types of interactions a protocol can have. One of these interactions is with a peer protocol. To exchange its state information with the peer, the protocol uses Protocol Data Units (PDUs). A PDU is essentially a block of information, which may be referred to by various names (e.g., frame, packet, segment) by various protocols.

A protocol’s purpose is to provide a service to another protocol in the same system. Generally, the serviced protocol is in the layer above the servicing protocol’s.
There are two types of information exchange between protocols: Interface Communication and Protocol Communication.

Protocols play a crucial role in ensuring seamless and efficient data exchange between two entities in a communication system. For two parties to communicate, they must have a common language, some common understanding about what symbols in the language stand for, and what rules are used for communication. Consequently, a communication protocol is a set of rules and conventions that allows two or more entities within a communication system to exchange information. The protocol defines the shared schema that includes the rules, syntax, semantics, and synchronization of communication.