Jun 15, 2023

Networking Appendix and OSI Layer

ARP        Address Resolution Protocol

DHCP     Dynamic Host Configuration Protocol
               A client/server protocol that automatically provides an Internet Protocol (IP) host with its IP address                and other related configuration information such as the subnet mask and default gateway

DNS       Domain Name System
               Translate IP address to domain name such 192.168.1.1 to www.4edt.com

CLI        Command Line Interface

FCS        Frame check sequence

LAN       Local Area Networks

NAT       Network Address Translation

NIC        Networks Interface Card

TCP        Transfer

OSI        Open Systems Interconnection

UDP                

VPN      Virtual Private Network, also called tunnels

WAP      Wireless Access Point
The device that enables a computer to connect wirelessly to a network. A WAP is a combination of a radio transmitter and a radio receiver and has an integrated wired network port.

 

slot_#/subslot_#/ port_#.

fa        Fast Ethernet

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Local, Remote              A resource such as a disk drive is local in your computer, and remote for resource in another computer.

Node                            A device that connects to network


Packet                          A message that is sent over the network from node to node. Packet begins with a preamble, which consists of 56 bits of alternating zero and ones.

Bus                              Network topology


DHCP Server

Gateway                     

Server                         

Client

Dedicated Server          Computer only have task to share source or working as server only.

Peer-to-peer server       Computer is working as server, but also can working as client.

Switch                          is box with a bunch of cable connector, computer on the network is connected by cable to the switch, then the switch connects all computers to each other.

Hubs                            Pair networking device.


Router                          A device found in nearly all networks and used to connect two networks (your internal network and the internet)

Firewall                        is an essential component of any networks to the internet, then provide security feature. In most cases, the function of a router in a single device called a firewall router.

Wireless router             in small home/office, a single device has function as firewall, router, WAP, and switch.

Tapping                       Single cable between node.

Backbone                     The bus that connect the switches

Header                        

Trailer                          A trailer or footer refers to supplemental data (metadata) placed at end of block of data being stored or transmitter, which may contain information for the handling of the data block, or simply mark the block’s end.

Parsing

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Preamble                      A network communications signal that synchronizes data transmission between two or more computer systems. Preamble is one of part of an ethernet data frame’s contents (Layer 1), define as the contents of a single data packet transmitted over an Ethernet connection. Consist of 56 bits of alternating ones and zeros.

Start-of-frame marker   SoF/SFD is a single byte that indicates that the frame is about to begin.

Destination MAC add   6-bytes

Sender MAC add         6-bytes

Tag                              The tag is used to support virtual local area (VLANs) and it is optional.

Ethertype                     2-bytes, this field indicates the specific protocol that is contained in the payload.

Payload                        In data transmission, Payload is also called as body. The payload contains the actual data being sent by the packet from 46-1500 bytes. If the sent packet is longer than 1500 bytes, the information must be broken into more packet, sent separately, and then reassembled when packet reach their destination.

FCS is 4-bytes, used to ensure that the frame data sent correctly. Basically, the interface that sends the packet uses an algorithm to calculate a 4-bytes number based on the contents of the frame and saves this number in the FCS field.

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Collision Packet           When two or more interface are shared on a single cable, there is have possibility the information sent in same time, and between packets will be destroyed in the process and need to be sent again.


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Layer 1 - Physical
  • Router
Layer 2 - Data Link
  • Switch Layer 2 (where focus on MAC address)
  • ARP
Layer 3 - Networks
  • SW3 or CS (focus on IP address)
  • ICMPv4 or ICMPv6
Layer 4 - Transport
  • Transport Protocol (TCP/UDP)
Layer 5 - Session
  • .
Layer 6 - Presentation
  • Presentation Protocol
Layer 7 - Application
  • Application Protocol