Internet Primer

IP Address

  • 32-bit address, unique identifier of computer on a network.
  • addressing scheme used by computers is known as IP addressing.
  • four cluster of 8-bits using decimal notation.

DHCP

  • to assign IP addresses to computers

DNS

  • help us translate IP addresses to human-comprehensible names.
  • analogy: yellow pages directory (business names into phone numbers).
  • there’s no really a DNS record of the entire internet.
  • DNS server like (Google) act like aggregators, collecting smaller sets of DNS information and pooling them together, updating frequently.
  • DNS record sets are thus fairly decentralized.
  • port 53.

Access Points

  • router behaves as a traffic cop (NAT) that allows data requests from all of the devices on your local network to be processed through a single IP address.
  • soho networks consist of access points that combines a router, a modem, a switch, and other technologies together into a single device.

TCP/IP

  • Internet Protocol (IP): connection-less protocol for getting information from a sending machine to a receiving machine.

  • Transmission Control Protocol (TCP) - directing the transmitted packet to the correct program on the receiving machine.

  • dictate how information is communicated from machine to machine and application to application (IP and TCP, respectively).

  • it is important to be able to identify where the receiver is and what the packet is for.

  • TCP and IP are inseparable pair (TCP/IP).

  • each program/utility/service on a machine is assigned a port number, coupled with IP address allows to uniquely identify a specific program on a specific machine.

  • TCP is crucial for guaranteeing delivery of packets.

  • TCP does by including:

    • information about how many packets the receiver should expect to get and in what order,
    • transmitting that information alongside the data.

TCP/IP Steps

when data is sent:

  • TCP breaks it into smaller chunks and communicates those packets to the computer’s network software, adding a TCP layer onto the packet.
  • IP routes the individual packages from sender to receiver; this info is part of the IP layer surrounding the packet.
  • on receiving end, TCP looks at the header to see which program it belongs to and present those packets to destination program into proper order.

HTTP

  • Hypertext Transfer Protocol
  • protocol for how to interpret the data that was sent.
  • application layer protocol which specifically:
    • dictates the format by which client request web pages from server and
    • the format via which server return information to clients.
method request-target http-version

--

GET / HTTP/1.1    ------------------------>   HTTP/1.1 200 OK
Host: cats.com                                Content-Type: text/html

RGB Representation

  • Why in Hexadecimal? convenient representation, makes easier to understand.
    • Hexadecimal -> #FF FF FF
    • Binary -> #11111111 11111111 11111111
    • Decimal -> #255 255 255
  • FF -> represents 255
# Deep Understanding
  16^1 = 16   16^0 = 1
      *          *
      F          F
  = 16 * 15 + 1 * 15 = 255

Big O vs Omega

  • Big O - upper bound (O)
  • Omega - lower bound (Ω)
  • Theta -> both same
  • space and time complexity are converse
  • bubble sort sometimes can win if already sorted.

Data Structure

  • orphaned memory leads memory leaks. (linked list)

Algorithms

Weird Algorithm

sleep_sort() {
  while [ -n "$1" ]
  do
    (sleep $1; echo $1) &
    shift
  done
  wait
}

DevOps

  • CI - Build/Test
  • CD - Release/Deploy

Mastering Kubernetes On-Premise & Cloud for Admins, Developers, DevOps & Architects

Kubernetes: Container Orchestration

Cloud native application

  • Cloud native is the software approach of building, deploying.

  • Fargate is serverless

  • add relevant description only.

  • argo cd

  • pre deployment charts