Part 1 Flashcards
All People Seem To Need Data Processing
Application, Presentation, Session, Transport, Network, Data Link, Physical
Physical Layer
Electronic signals creating connection. Physical wires, ports, or wireless communication. Data is transferred as bits.
Data Link Layer
Also called Data Link Control Layer or MAC layer. Describes the ethernet connection between two NIC cards. These NIC cards will have MAC (Media Access Control) Addresses to identify source and destination. Switches handle device communication via MAC addresses.
Network Layer
The IP (Internet Protocol) layer. Describes how devices route information to other devices located in a different network.
Transport Layer
Transportation protocols including TCP and UDP that negotiate and or establish connections between devices. These protocol also have designated ports for different types of traffic.
Session Layer
Session management that connects and controls information flow. Connects Application and Presentation layer data to the rest of the OSI stack layers.
Presentation Layer
Manages SSL/TLS encryption of data communication.
Application Layer
Data that you see and interact with within an application on your screen.
PDU
Packet Datagram Unit - Each layer of the OSI model encapsulates data from the layer above it often between and head and tail packet. The layer doing the encapsulation does not care what the data within it is. The encapsulating layer will reference the head and tail packets of the encapsulated data to know where the data needs to be sent and other meta data.
MTU
Maximum Transmission Unit - Maximum amount of bytes allowed over a connection before a packet is required to be fragmented. Packet fragmentation can slow down a connection as the packets have to be reconstructed by the receiving node. Fragmentation also increases the chances of data loss/failed connection.
Peer to Peer
All devices are both clients and servers. Easy to deploy and cheap. Difficult to administer and secure.
Client-Server
Central server that clients talk to each other through. Better performance and easier administration. More expensive and complex.
LAN
Local Area Network : Local is relative. Could be a building or group of building. Consists of ethernet or wireless (802.11) connections to provide high speed connectivity.
MAN
Metropolitan Area Network : A network in your city. Larger than a LAN but smaller than a WAN. Common for government organizations who own fiber cabling around a city.
WAN
Wide Area Network: Spanning the globe. Generally connects LANs across a distance. Generally much slower than a LAN. Many different WAN connections such as satellite, point to point serial, fiber, etc.
WLAN
Wireless LAN: 802.11 Technologies. Within a building (geofencing). Can expand coverage with additional access points.
PAN
Personal Area Network: Your own private network. Consists of Bluetooth, IR, NFC. Includes tech like headphones, cars, workout telemtry.
CAN
Campus Area Network: Limited geographical area network, or a group of buildings. Fiber connected or through high speed ethernet.
NAS
Network Attached Storage: Connected to a shared storage device across the network. File level access, so any changes you make to the file have to be made to the entire file. Requires a lot of connection bandwidth.
SAN
Storage Area Network: Looks and feels like a local storage device (Block level access). Very efficient reading and writing. Requires a lot of bandwidth.
MPLS
Multiprotocol Label Switching: Labels traffic moving through WAN connection. Allows for transport for any medium and any protocol inside. A common WAN technology. Labels are pushed onto packets as they enter the MPLS cloud. Labels are popped off on the way out.
mGRE
Multipoint Generic Router Encapsulation: Used extensively for Dynamic Multipoint VPN and common for CISCO routers. Your VPN builds itself and remote sites communicate to each other. Tunnels are built dynamically on demand.
SD-WAN
Software Defined WAN: a WAN built for the cloud. Datacenters used to be in one place. Cloud based applications communicate directly to cloud resources instead of through a datacenter. Data is forwarded to a destination based on its traffic.
Demarcation Point
The point where you connect to the internet via ISP or WAN provider. Used everywhere in offices and buildings. This is what you connect you customer premises equipment such as routers and switches.
Smartjack
A smart network interface unit (NIU) that determines the demarc and provides built in diagnostics such as loopback tests and alarm indicators.
NFV
Network Function Virtualization: Virtualize all physical network devices and manage from a hypervisor. Quickly and easily deploy network functions with many different deployment options like VMs, Containers, fault tolerance, etc.
Hypervisor
Virtual machine manager for the virtual platform and guest operating systems. Hardware manager and allows for single console control.
vSwitch
Virtual Switch with same functionality as a physical switch. Can do link aggregation, port mirroring, forwarding options, netflow. Deployed from the hypervisor.
vNIC
Virtual NIC: virtual devices need a network interface. Can be configure and connected through a hypervisor.
Satellite networking
Communication to a satellite. High cost relative to terrestrial networking and made for remote sites. High latency that requires high frequencies for comms.
Copper
Extensivley used because its cheap and easy to install and maintain. Limited bandwidth availability because of physics limiting electronic signals over copper. Used in wide area networks such as cable modem and DSL. Often combined with fiber that resides on the backbone of a connection.
DSL
Digital Subscriber Line: Uses pre-existing phone lines. Download speeds are faster than upload speeds (asymmetric). Faster speeds are possible depending on proximity to a central office location (CO).
Cable Broadband
Broadband comms with transmission across multiple frequencies and different types of traffic. Use a specific standard called DOCSIS (Data Over Cable Service Interface Specification). Broadband speeds will vary depending on DOCSIS spec in use.