(F) Chapter 1 Network concepts Flashcards
What is Network Edge?
Network edge includes the devices and local networks that connect-end-users or clients to the broader internet. This includes both wired and wireless systems such as local area networks (LANs), home networks, and enterprise networks.
examples
- hosts: (end systems like computers, smartphone, and servers)
- access networks: (networks physically connect end systems to the first (known as “edge routers”. Residential, institutional, or mobile access networks
- connection types: connections at the edge can be wired or wireless
- functions: primary function of the network edge is to facilitate user access to internet resources, sending and receiving data packets to and from the network core
What is Network Core?
Network Core - is a mesh of interconnected routers that handle the data transmission across the Internet. The core’s main function is to forward packets, which are segments of data sent over the network. This forwarding process is based on routing algorithms that determine the optimal paths for data to travel from the source to its destination. Essentially, the network core is the central part of the Internet that manages the data traffic between various network edges (like homes, businesses, and data centers).
examples
- routers: these devices manage traffic within the core, directing data packets from one destination to another via the most efficient route available
- function: the core primarily uses packet-switching technology, whee data is broken down into packets and sent to the destination, allowing for more efficient use of the network
Network edge vs network core?
Edge focuses on connectivity and direct user access, serving as the entry point for data packets into the network. Facilitate communication between devices and local networks, including wired and wireless systems such as LANs, home networks, and enterprise networks.
Core is dedicated to transporting data packets through the network backbone, efficiently routing data packets between different networks and handling high-speed data tansfer (mesh of interconnected routers like national or global isp or regional isp).
Common terms;
- Network edge: refers to the part of the network where devices (hosts) connect) to and and access the network, using various access networks
- Network core: (mesh of interconnected routers)involves routers and data paths that move data across large distances. It is part of the network that interconnects different edge networks
- Protocols: sets of rules defining how data is transmitted over an network. Protocols specific the mechanisms for data transmission, signaling, authentication, and error handling
- Router: a device that forwards data packets between computer networks, directing traffic based on the headers and forwarding tables to determine the best path for data transfer
- Packet Switching: a networking method where data is broken (application-layer messages) into packets before before being sent, allowing for efficient, flexible routing through different network paths.
- Circuit switching: method of data transmission where a dedicated channel must be establishes for the duration of transmission session, commonly used in traditional telephone networks
- Multiplexing: a method to combine multiple signals or data streams into one signal over a shared medium. Common methods are Frequency Division Multiplexing (FDM) and Time Division Multiplexing (TDM)
- Demultiplexing: The process of receiving data from a single source and routing it towards the appropriate receiver endpoint. Typically happens at the receiving end.
- Throughput: the rate at which data is successfully transferred over a communication channel. This can be measured in bits per second Indicates how much actual data can be sent through a network at a given time
- Packet Loss: the situation in which one or more data packets fail to reach their destination. This can occur due to errors in data transmission, network congestion, hardware failure, or incorrect routing
- Latency: the delay before a transfer of data begins following an instruction for its transfer
- Transmission rate (bandwidth): the rate at which data is transmitted over a communication channel, usually measured in bits per second (bps)
What are 5 Layered internet protocol stack
- Application Layer: Provides protocols that application use to exchange data over HTTP, IMAP, DNS) // (where apps like web browsers and email get the data they need to work) //
- Transport: protocol transfers from one process to another // (moves data directly between computers, ensuring it’s reliable or fast, as needed) //
- Network: routing of datagrams from source to destination (IP, routing protocols)
- Link: data transfer between neighboring network elements (Ethernet, 802.11 (WiFi)
- Physical: bits: “on the wire”:
Analogy of air travel (5 stack layers)
- ticket (purchase)
- baggage (check)
- gates (load)
- runway takeoff
- airplane routing
to airplane routing
- airplane routing
- runway landing
- gates (unload)
- baggage (claim)
- ticket (complain)
Network securities
- packet “sniffing”: involves intercepting and examining data packets traveling across a network for monitoring or potential security threats
- IP spoofing (fake identity): technique where an attacker manipulates the source IP address in a network packet to impersonate another system (injection of packet with false source address)
- Denial of Service (DoS): attackers make resources (server, bandwidth) unavailable to legitimate traffic by overwhelming resource with bogus traffic)
// (select target –> break into host –> send packets to target from compromised hosts)
Lines of defense:
- authentication: proving you are who you say you are
- confidentiality: via encryption
- integrity checks: digital signatures prevent/detect tampering
- access restrictions: password-protected VPNs
- firewalls: specialized “middleboxes” in access and core networks
