Network + Certification Week One

OSI Model

Hierarchical model that defines network functionality

Physical Layer

Layer 1 of the OSI Model, deals with electrical and mechanical characteristics

Data Link Layer

Layer 2 of the OSI Model, handles flow control, acknowledgments, and access to media

Logical Link Control (LLC)

Sublayer of Layer 2, responsible for communication with the upper layer

Media Access Control (MAC)

Sublayer of Layer 2, responsible for communication with the lower layer

Network Layer

Layer 3 of the OSI Model, handles routing and logical addressing

Transport Layer

Layer 4 of the OSI Model, includes TCP and UDP protocols

TCP

Connection-oriented protocol in the Transport Layer, provides reliable delivery

UDP

Connectionless protocol in the Transport Layer, provides best effort delivery

Session Layer

Layer 5 of the OSI Model, establishes, maintains, and terminates session communication

Presentation Layer

Layer 6 of the OSI Model, formats application data

Application Layer

Layer 7 of the OSI Model, provides applications network access

Traditional TCP/IP Model

True implementation of the Internet

Encapsulation

Process of adding headers from each layer to the data

Ethernet header

Layer 2 header, includes MTU (maximum transmission unit)

Internet Protocol (IP) header

Layer 3 header

Transmission Control Protocol (TCP)/User Datagram Protocol (UDP) headers

Headers in the Transport Layer

TCP flags

Flags used in the TCP header for various purposes

Payload

Data carried by the packet

Decapsulation

Process of removing headers to display data to the application layer

Mesh Topology

Each computer is connected to every other computer

Star/hub-and-spoke Topology

Centralized connectivity device with each device connected to it

Bus Topology

All nodes connected to the same linear backbone cable

Ring Topology

Unidirectional communication in a ring

Hybrid Topology

Combination of two or more topologies

Peer-to-peer Network

Each computer provides services and requests from other computers

Client-server Network

Computers access services provided by a server

Local Area Network (LAN)

Devices connected to a network within a geographical location

Metropolitan Area Network (MAN)

Network owned by a single organization within a city limit

Wide Area Network (WAN)

Network that spans a large geographic area

Wireless Local Area Network (WLAN)

LAN using wireless access points

Personal Area Network (PAN)

Devices connected to one person's workspace

Campus Area Network (CAN)

Interconnection of LANs within a limited geographical area

Storage Area Network (SAN)

High-speed fiber optic communications for quick file access

Software-defined Wide Area Network (SDWAN)

Virtualized WAN using software-defined networking

Multi-label Protocol Switching (MPLS)

Routing technique based on labels rather than network addresses

Multipoint Generic Routing Encapsulation (mGRE)

Routing technique for multiple endpoints

Virtualization

Creating a logical representation of components through software

Host Machines

Physical machines hosting virtual components

Virtual Machines

Software-based resources running OSs like physical devices

Type 1 Hypervisor

Bare metal hypervisor without an OS running on the machine

Type 2 Hypervisor

Hypervisor installed like an application

Virtual Network Adapters

Host machine's physical network adapter seen as the physical adapter to VMs

Virtual Networks

Host machine's network adapter acting as a virtual switch for VMs

Network Functions Virtualization (NFV)

VMs providing network services as dedicated functions

Satellite Link

Media: radio-waves, Speeds: 10-100 Mbps, Line-sight communication

Digital Subscriber Line (DSL)

Broadband internet access over traditional copper telephone lines

Cable Link

Internet access using cable TV infrastructure

Leased Lines

Dedicated bandwidth for customers

Metro-optical or MetroEthernet

Ethernet-based networks connecting metropolitan areas

Synchronous Optical Networking (SONET)/Synchronous Digital Hierarchy (SDH)

Fiber optic networks with dual-ring topology

T-Carriers

Digital signal carriers for voice and data communications

Integrated Services Digital Network (ISDN)

Digital telephone network for voice and data transmission

Copper Cables

Twisted pair cables used for networking

Plenum

Cable rated for HVAC spaces

Non-Plenum

Cable not rated for HVAC spaces

Connector Types

RJ11, RJ45, F-type connector

Termination Standards

Standards for wiring termination, e.g., TIA/EIA-568A, TIA/EIA-568B

Media Converters

Devices to convert between different types of media

Fiber Cables

Optical cables used for networking

Connector Types

LC, ST, SC, MT, RJ, APC, UPC

Transceivers

Devices for transmitting and receiving data over fiber

Ethernet Standards

Standards for Ethernet networks, e.g., 10BASE-T, 100BASE-TX

Cable Management

Organizing and managing network cables

Patch Panel/Patch Bay

Panel for connecting and managing network cables

Fiber Distribution Panel

Panel for connecting and managing fiber cables

Punch-down Block

Connector for terminating network cables

66 Block

Connector for terminating network cables

110 Block

Connector for terminating network cables

Krone Block

Connector for terminating network cables

Bix Block

Connector for terminating network cables