Network Programming Chapter 1( 1.1-1.7)

Host / End System

Computing devices connected to a network (PCs, servers, IoT devices) that run applications.

Packet Switch

A device (router or link-layer switch) that takes incoming data packets and forwards them toward their destination.

Internet Protocol (IP)

Defines the addressing and routing structure for packets across the Internet.

IETF / RFC

Internet Engineering Task Force; defines Internet standards through official documents called Requests for Comments.

Application Programming Interface (API)

Set of rules specifying how a software program interacts with the network infrastructure.

DSL (Digital Subscriber Line)

High-speed Internet access using traditional telephone copper lines to a central office.

Cable / DOCSIS

Broadband access over a hybrid fiber-coaxial network; shared transmission medium among nearby users.

FTTH (Fiber to the Home)

Direct optical fiber connection from a central office to homes offering very high symmetric speeds.

Guided vs. Unguided Media

Guided media directs signals along solid paths (copper, fiber); unguided media transmits through air/space (Wi-Fi, satellite).

Store-and-Forward Transmission

Packet-switching principle where a switch must receive an entire packet before sending its first bit onto the next link.

Path of N links each of rate R

-There are N-1 Routers between source and destination

Packet Switching vs. Circuit Switching

Packet switching shares bandwidth on demand (bursty traffic); circuit switching reserves dedicated end-to-end capacity.

FDM vs. TDM

Frequency-Division Multiplexing splits link capacity into frequency bands; Time-Division Multiplexing splits capacity into repeating time slots.

Internet Exchange Point (IXP)

A physical infrastructure where multiple ISPs peer and exchange network traffic directly.

Transmission Delay vs. Propagation Delay

Transmission delay (L/R) is time to push bits onto the link; Propagation delay (d/s) is physical travel time across the medium.

Queuing Delay & Loss

Time spent waiting in router buffers; occurs when arrival rate exceeds link capacity, leading to packet drops if buffers overflow.

Traffic Intensity

Formula (L * a) / R; as it approaches 1, queuing delay grows exponentially toward infinity.

Bottleneck Link

The link along an end-to-end path with the lowest transmission capacity, determining max throughput.

Internet Protocol Stack (5 Layers)

Application, Transport, Network, Link, Physical.

OSI Model Extra Layers

Presentation (formatting, encryption) and Session (checkpointing, synchronization); handled within the application layer in IP.

Encapsulation

The process where each lower layer wraps data from the layer above with its own header information.

Virus vs. Worm

A virus requires human action/interaction to spread; a worm self-replicates autonomously across networks.

Distributed Denial of Service (DDoS)

Flooding a target server with bogus traffic from multiple compromised nodes (botnet) to overwhelm resources.

Packet Sniffing

Passively reading and copying data packets traversing a shared physical medium.

IP Spoofing

Injecting packets into a network with a forged source IP address to disguise identity.

ARPANET

The precursor to the modern Internet, funded by DARPA; first node deployed in 1969.

TCP/IP Development

Key internetworking protocols created by Vint Cerf and Bob Kahn to unify disparate networks.

Routing

Determines Source-destination route taken by packets

Forwarding

Moves Packets from router’s input to appropriate router output

Routing V Forward

Routing knows the algorithims, forwarding actually moves the packets to each output.

Network Core

Mesh of interconnected routers

Network edge

End Systems(Hosts): runs application programs

What are the 2 models of communication in the network edge?

Client/Server(web browser)

Peer to Peer(Skype or Bit-Torrent) (No central server)

What do Modems do?

Transfer network from digital to signal

Communication Links

Transmission media like fiber, copper, radio, and satelite. Defined by Bandwidth