ComputerNetwork:Basic

lastmod 2026-01-05created 2022-10-0629 edits

Computer network basics.

Equipment

• Network switch - Includes the differences between hubs, switches, and routers.

Addressing

• Port Number
• IP Address
  • ipcalc makes it easy to explain.
  • Classless Inter-Domain Routing (cider; CIDR) A classless inter-domain routing technique. Written like 192.168.0.0/16.
• Mac Address
• netplan - To set a static IP on Ubuntu, see Netplan#How to set a static IP.

Tables

• Master the three tables and LAN communication is done!! - Goduck2-LAN-1.pdf

All you need to know are the three tables:

• Routing Table
• ARP Table
• Mac Table

About routing

• Network address translation (NAT)
• Subnet

Terms

• LAN/WAN
• VLAN
• OSI 7 Layer
• Hub
• Network switch (Switching Hub)
• Router
• Address Resolution Protocol (ARP)
• Private network
• Subnetwork

Protocols

• TCP
• Time to live (TTL)
• UDP
• IP
• IP Address
• Network classes (Classful network)
• ICMP

Linux

• Linux namespace
• brctl - linux bridge configuration

Tools

• traceroute
• ping

Network simulation

• Cisco Packet Tracer
• GNS3

Oridengi's LAN communication stories

1. Master the three tables and LAN communication is done!! - Goduck2-LAN-1.pdf
2. ARP is the flower of Ethernet communication - Goduck2-LAN-2.pdf
3. Ethernet switches are Plug & Play? - Goduck2-LAN-3.pdf
4. How is the Routing Table related to the Router? - Goduck2-LAN-4.pdf
5. What if there were no Proxy ARP? - Goduck2-LAN-5.pdf
6. Gratuitous ARP is so handy, yet it's called the freebie ARP? - Goduck2-LAN-6.pdf
7. Subnet, subnets, Subnet Mask - Goduck2-LAN-7.pdf
8. VLAN - I want to know. - Goduck2-LAN-8.pdf
9. Without a tag (VLAN Tag), is it a native (Native)? - Goduck2-LAN-9.pdf

Oridengi's routing stories

1. Connected - IP networking, the start of routing - 1/3
2. Connected - IP networking, the start of routing - 2/3
3. Connected - IP networking, the start of routing - 3/3
4. Static Routing starts with PCs and servers

Network engineer Hwanyeong's tech blog: Understanding L4 switches easily

"Understanding Network Infra easily/Understanding L4 & L7 Network easily" series

1. Understanding Port easily - Easy_to_understand_L4_switch_-_01.pdf (Port Number)
2. Understanding TCP/IP easily - Easy_to_understand_L4_switch_-_02.pdf (TCP/IP)
3. Understanding server load balancing easily - Easy_to_understand_L4_switch_-_03.pdf
4. Understanding L4 switches easily #1 (overview and role of L4 switches) - Easy_to_understand_L4_switch_-_04.pdf
5. Understanding L4 switches easily #2 (Traffic Flow) - Easy_to_understand_L4_switch_-_05.pdf
6. Understanding L4 switches easily #3 (NAT) - Easy_to_understand_L4_switch_-_06.pdf (NAT)
7. Understanding L4 switches easily #4 (3-way handshake) - Easy_to_understand_L4_switch_-_07.pdf (TCP)
8. Understanding L4 switches easily #5 (the Source IP NAT problem) - Easy_to_understand_L4_switch_-_08.pdf (NAT)
9. Understanding L4 switches easily #6 (solving the Source IP NAT problem) - Easy_to_understand_L4_switch_-_09.pdf (NAT)
10. Understanding L4 switches easily #7 (SSL Offload) - Easy_to_understand_L4_switch_-_10.pdf (SSL)
11. Understanding L4 switches easily #8 (Health Check / Connection / Sticky) - Easy_to_understand_L4_switch_-_11.pdf
12. Understanding L4 switches easily #9 (1, network configuration) - Easy_to_understand_L4_switch_-_12.pdf
13. Understanding L4 switches easily #9 (2, network configuration part two) - Easy_to_understand_L4_switch_-_13.pdf
14. Understanding L4 switches easily #10 (redundancy) - Easy_to_understand_L4_switch_-_14.pdf
15. Understanding L4/L7 load balancing easily - Easy_to_understand_L4_switch_-_15.pdf (L4/L7/Load Balancing)
16. Understanding NAT easily - NAT_easy_to_understand.pdf (NAT)
17. Understanding Source IP NAT easily - Easy_to_understand_L4_switch_-_17.pdf (NAT)
18. Understanding Destination IP NAT easily - Easy_to_understand_L4_switch_-_18.pdf (NAT)
19. Understanding SNMP easily #1 - Easy_to_understand_SNMP_1.pdf (SNMP)
20. Understanding SNMP easily #2 - Easy_to_understand_SNMP_2.pdf (SNMP)

See also

• Computer Network