Protocol Architecture - IE1030 Data Communication Networks

Vocabulary flashcards covering networking protocols, layered architectures, the TCP/IP stack, PDUs, encapsulation, device layering, Wi-Fi frame exchange, and the OSI model from IE1030 Data Communication Networks.

Protocol

A set of rules defining the format of messages, the order of messages sent and received among network entities, and the actions taken upon sending, receiving, or failing to receive a message.

Protocol Data Unit (PDU)

A discrete unit of data or message exchanged between peer layers of a protocol across a network.

Timeout

An event that occurs when an expected response or acknowledgment is not received within a pre-defined period of time after a message has been sent.

DIFS (Distributed Inter-Frame Space)

The specified time period ($34\,\mu\text{s}$ in Wi-Fi) that a sender must wait while the wireless medium is clear before issuing a Request to Send (RTS) frame.

SIFS (Short Inter-Frame Space)

A short time interval ($16\,\mu\text{s}$ in Wi-Fi) that stations wait between receiving a frame and transmitting a corresponding response, such as RTS to CTS, CTS to Data, or Data to ACK.

Request to Send (RTS)

A control frame sent by a Wi-Fi source station to the intended recipient station to request permission to transmit data over the channel.

Clear to Send (CTS)

A control frame transmitted by the destination station in response to an RTS, informing the sender that it can transmit data and telling other stations to remain quiet.

Network Allocation Vector (NAV)

A timer maintained by Wi-Fi stations instructing them to keep quiet and defer transmission for a duration specified in RTS and CTS messages.

Wi-Fi Four-Frame Exchange

A medium-access procedure where the source sends an RTS after DIFS, the destination responds with CTS after SIFS, the source transmits Data after SIFS, and the destination sends an ACK after SIFS.

Protocol Architecture

A layered framework that breaks the complex task of network communication into smaller, specialized subtasks performed by independent layers.

Peer Layers

Corresponding layers located on different communicating hosts that interact and communicate directly with each other using a protocol specific to that layer.

Application Layer

The top layer of the TCP/IP protocol stack where network applications and user-facing protocols reside (e.g., HTTP, SMTP, DNS, IMAP).

Transport Layer

The layer of the TCP/IP stack responsible for process-to-process data delivery between application endpoints, primarily using TCP or UDP.

Transmission Control Protocol (TCP)

A transport-layer protocol providing a connection-oriented, reliable service with guaranteed message delivery between communicating processes.

User Datagram Protocol (UDP)

A transport-layer protocol providing a lightweight, connectionless service with no delivery guarantees or reliability mechanisms.

Network Layer (IP Layer)

The layer responsible for routing and delivering datagrams from the source host to the destination host across networks, primarily using the Internet Protocol (IPv4 or IPv6).

Link Layer

The protocol layer responsible for moving data between neighboring network elements along a transmission path (e.g., via Ethernet or Wi-Fi).

Physical Layer

The lowest layer of the protocol stack that transports individual raw bits ($1\text{s}$ and $0\text{s}$) over a physical transmission medium.

Message

The specific Protocol Data Unit (PDU) generated and exchanged at the application layer.

Segment

The specific Protocol Data Unit (PDU) generated at the transport layer by encapsulating an application-layer message with a transport header ($H_t$).

Datagram

The specific Protocol Data Unit (PDU) generated at the network layer by encapsulating a transport-layer segment with a network header ($H_n$).

Frame

The specific Protocol Data Unit (PDU) generated at the link layer by encapsulating a network datagram with a link header ($H_l$) and typically a link trailer ($T_l$).

Encapsulation

The process of wrapping data from an upper layer with a header (and sometimes a trailer) at a lower layer as it traverses down the protocol stack.

De-encapsulation

The process of stripping away headers and trailers from received data as it travels up the protocol stack to retrieve the original payload.

Layer 3 Device

A network device, such as a router, that implements the lowest three layers of the protocol stack: Physical, Link, and Network.

Layer 2 Device

A network device, such as a switch, that operates only at the lowest two layers of the protocol stack: Physical and Link.

OSI Reference Model

A theoretical seven-layer network architecture designed by the International Standards Organization (ISO) comprising Physical, Data Link, Network, Transport, Session, Presentation, and Application layers.

Presentation Layer

The sixth layer in the OSI reference model whose functions (e.g., data formatting and interpretation) are incorporated directly into the application layer within the TCP/IP stack.

Session Layer

The fifth layer in the OSI reference model whose functions are handled by the transport and application layers within the TCP/IP stack.