NETWORK & NETWORKING

IMP NOTES:
To excel in network engineering, especially
when focusing on network, hardware,
and software, you should have a solid
understanding of the following topics:

1. Network Basics
 Networking Fundamentals:
o OSI Model & TCP/IP Model
o IP Addressing (IPv4, IPv6)
o Subnetting and CIDR (Classless Inter-Domain Routing)
o MAC Addressing
 Network Devices:
o Routers, Switches, Hubs, Modems, Access Points,
gateways
o Firewalls (Hardware & Software)
 Network Topologies:
o Star, Mesh, Ring, Bus, Hybrid
 Protocols:
o TCP/IP, UDP, ARP, DNS, DHCP, HTTP/HTTPS
o SMTP, POP3, IMAP for emails
 o FTP/SFTP for file transfer

2. Hardware Knowledge
 Network Equipment Configuration:
o Configuring routers and switches
o Wireless Access Points setup
 Cabling and Connectivity:
o Ethernet Cables (Cat5, Cat6, Fiber Optics)
o Structured Cabling Standards
o RJ45 Connectors and Patch Panels
 Hardware Troubleshooting:
o Diagnosing connectivity issues
o Testing and replacing faulty cables and devices
 Network Interface Cards (NIC):
o Understanding NIC configurations and drivers

3. Software Skills
 Network Operating Systems:
o Cisco IOS, Juniper Junos
o Windows Server and Linux (Red Hat, Ubuntu)
 Network Configuration and Monitoring Tools:
o Wireshark (Packet Analysis)
o Nmap (Network Scanning)
o SolarWinds, Nagios, or Zabbix (Monitoring Tools)
 o SNMP (Simple Network Management Protocol)
 Firewall & Security Software:
o Palo Alto, Fortinet, pfSense
 Virtualization and Cloud:
o VMware, Hyper-V, VirtualBox
o Basics of AWS, Azure, Google Cloud Networking

4. Advanced Networking
 Routing and Switching:
o Static and Dynamic Routing (OSPF, BGP, RIP)
o VLANs, Trunking, and Spanning Tree Protocol (STP)
 Wireless Networking:
o Wi-Fi Standards (802.11 a/b/g/n/ac/ax)
o Wireless Security (WPA, WPA2, WPA3)
 Software-Defined Networking (SDN):
o OpenFlow, Cisco ACI
 Network Automation and Scripting:
o Python for automation (Netmiko, Paramiko, Nornir)
o Ansible for configuration management

5. Security
 Network Security Basics:
o Firewalls, VPNs, Proxy Servers
o Intrusion Detection and Prevention Systems (IDS/IPS)
  Encryption and Authentication:
o SSL/TLS, IPsec, RADIUS, TACACS+
 Threat Analysis:
o Common attacks (DDoS, MITM, Phishing)
o Penetration Testing Basics

6. Scripting and Automation

 Scripting Languages:
o Python, Bash, PowerShell
 Automation Tools:
o Ansible, Terraform, Puppet, Chef
 Version Control:
o Git and GitHub for managing scripts

7. Cloud Networking
 Basics of Cloud Infrastructure:
o AWS VPC, Azure Virtual Network, GCP Networking
 Load Balancers:
o ELB (AWS), NLB, Application Gateways
 Hybrid Networks:
o Integration of on-premise networks with cloud

8. Soft Skills
 Troubleshooting:
 o Identifying and solving network issues efficiently
 Documentation:
o Maintaining network diagrams and change logs
 Communication:
o Explaining technical issues to non-technical stakeholders
o

Network Management:
 Network monitoring tools (SNMP, Nagios, PRTG)
 Performance analysis and optimization
 Troubleshooting and problem-solving techniques

Do you need help focusing on any specific area?

Here is a list of 30 important protocols and their
associated port numbers commonly used in
networking:
Protocol Name Port Number

File Transfer Protocol (FTP) - Data 20

File Transfer Protocol (FTP) - Control 21

Secure Shell (SSH) 22

Telnet 23

Simple Mail Transfer Protocol (SMTP) 25

Domain Name System (DNS) 53

Dynamic Host Configuration Protocol

67
(DHCP) - Server

Dynamic Host Configuration Protocol

68
(DHCP) - Client

Trivial File Transfer Protocol (TFTP) 69

Hypertext Transfer Protocol (HTTP) 80

Post Office Protocol (POP3) 110

Network News Transfer Protocol

119
(NNTP)

Internet Message Access Protocol

143
(IMAP)

Simple Network Management Protocol

161, 162
(SNMP)

Lightweight Directory Access Protocol

389
(LDAP)

Hypertext Transfer Protocol Secure 443

Protocol Name Port Number

(HTTPS)

Internet Control Message Protocol

N/A
(ICMP)

Secure File Transfer Protocol (SFTP) 22 (over SSH)

Remote Desktop Protocol (RDP) 3389

Border Gateway Protocol (BGP) 179

Kerberos 88

Network Time Protocol (NTP) 123

Syslog 514

Session Initiation Protocol (SIP) 5060, 5061

Server Message Block (SMB) 445

Internet Relay Chat (IRC) 194

Dynamic (1024–
Real-time Transport Protocol (RTP)
65535)

Dynamic (1024–
Voice over IP (VoIP)
65535)

Virtual Private Network (VPN - IPSec) 500, 4500

OpenVPN 1194
This list highlights critical protocols across various
domains like data transfer, communication, security,
and network management. Let me know if you'd like
explanations for any of these!
1. File Transfer Protocol (FTP) [20, 21]

Usage: Transfers files between a client and a server.

2. Secure Shell (SSH) [22]

Usage: Securely accesses and manages devices

remotely.

3. Telnet [23]

Usage: Provides remote access to devices (insecure,

replaced by SSH).

4. Simple Mail Transfer Protocol (SMTP) [25]

Usage: Sends emails between servers or from clients

to servers.

5. Domain Name System (DNS) [53]

Usage: Translates domain names into IP addresses.

6. Dynamic Host Configuration Protocol (DHCP)

[67, 68]

Usage: Assigns dynamic IP addresses to devices on a

network.

7. Trivial File Transfer Protocol (TFTP) [69]

Usage: Transfers small files without authentication.

8. Hypertext Transfer Protocol (HTTP) [80]

Usage: Transfers web pages and data on the internet.

9. Post Office Protocol (POP3) [110]

Usage: Downloads emails to a client from a server.

10. Network News Transfer Protocol (NNTP) [119]

Usage: Accesses newsgroups and distributes news

articles.

11. Internet Message Access Protocol (IMAP)

[143]

Usage: Accesses emails on a server without

downloading them.

12. Simple Network Management Protocol

(SNMP) [161, 162]

Usage: Monitors and manages devices on a network.

13. Lightweight Directory Access Protocol (LDAP)

[389]

Usage: Accesses and maintains directory information,

like user data.

14. Hypertext Transfer Protocol Secure (HTTPS)

[443]

Usage: Encrypts data transfer for secure web

browsing.

15. Internet Control Message Protocol (ICMP) [No

port]

Usage: Diagnoses network issues (e.g., ping).

16. Secure File Transfer Protocol (SFTP) [22]

Usage: Securely transfers files over SSH.

17. Remote Desktop Protocol (RDP) [3389]

Usage: Remotely accesses Windows desktops and
applications.

18. Border Gateway Protocol (BGP) [179]

Usage: Routes internet traffic between networks.

19. Kerberos [88]

Usage: Provides secure authentication for services and

users.

20. Network Time Protocol (NTP) [123]

Usage: Synchronizes clocks across devices.

21. Syslog [514]

Usage: Collects and stores system logs from devices.

22. Session Initiation Protocol (SIP) [5060, 5061]

Usage: Establishes, manages, and terminates VoIP

calls.

23. Server Message Block (SMB) [445]

Usage: Shares files, printers, and resources in Windows

networks.

24. Internet Relay Chat (IRC) [194]

Usage: Enables real-time text-based chat.

25. Real-time Transport Protocol (RTP) [Dynamic]

Usage: Transmits audio and video in real-time

applications.

26. Voice over IP (VoIP) [Dynamic]

Usage: Supports voice communication over IP
networks.

27. Virtual Private Network (VPN - IPSec) [500,

4500]

Usage: Secures private network communication over

public networks.

28. OpenVPN [1194]

Usage: Provides secure VPN connections.

29. Hypertext Transfer Protocol (QUIC/HTTP3)

[443]

Usage: Optimizes secure and fast data transfer for web

browsing.

30. Traceroute (ICMP or UDP) [Dynamic]

Usage: Tracks the path data takes across a network.

Let me know if you need further details about these

protocols!

CMD COMMANDS
Here is a list of 20 essential system commands and
20 networking commands for CMD:

20 Important System Commands

1. dir: Lists files and directories in the current

location.

2. cd: Changes the current directory.

3. cls: Clears the CMD screen.

4. echo: Displays messages or sets variables.

5. tasklist: Lists all running processes.

6. taskkill: Terminates a running process.

7. systeminfo: Displays detailed system information.

8. chkdsk: Checks the disk for errors.

9. sfc: Scans and repairs corrupted system files.

10. shutdown: Shuts down or restarts the

system.

11. wmic: Queries system information (e.g., CPU,

OS).

12. tree: Displays the directory structure in a tree

format.

13. format: Formats a disk.

14. diskpart: Manages disk partitions.

15. attrib: Changes file attributes (read-only,

hidden).
 16. fc: Compares two files.

17. set: Displays or sets environment variables.

18. ver: Displays the Windows version.

19. reg: Edits or queries the Windows registry.

20. bootcfg: Configures boot parameters.

20 Important Networking Commands

1. ping: Tests network connectivity to a host.

2. ipconfig: Displays network adapter configuration.

3. tracert: Traces the route to a network destination.

4. nslookup: Resolves domain names to IP

addresses.

5. netstat: Displays active network connections.

6. arp: Displays or modifies the ARP table.

7. route: Displays or modifies the routing table.

8. telnet: Tests connectivity to specific ports on a

server.

9. ftp: Transfers files via FTP.

10. netsh: Configures network settings and

interfaces.

11. getmac: Retrieves the MAC address of

network adapters.

12. pathping: Combines ping and tracert for

network diagnostics.
 13. hostname: Displays the hostname of the
system.

14. net use: Connects or disconnects shared

resources.

15. net share: Displays shared network

resources.

16. net accounts: Displays user account policies.

17. nbtstat: Displays NetBIOS statistics and

connections.

18. net view: Lists available shared resources on

a network.

19. powercfg: Configures power settings (e.g.,

wireless adapter performance).

20. nslookup -type=mx: Retrieves mail

exchange (MX) DNS records.

Each of these commands has specific flags and options

for enhanced functionality. Let me know if you'd like
detailed explanations or examples for any of them!

As a network engineer, mastering CMD commands for

daily tasks is crucial. Here’s a list of essential
commands you should practice, categorized by their
utility, to prepare for job scenarios and daily operations
in the office:
Daily Use Networking
CMD Commands
1. Basic Network Connectivity

1. ping: Test connectivity to a specific IP or domain.

o Example: ping 8.8.8.8.

2. tracert: Trace the route packets take to reach a

destination.

o Example: tracert www.google.com.

3. pathping: Combines ping and tracert for more

detailed diagnostics.

o Example: pathping www.example.com.

2. IP Configuration and Management

4. ipconfig: View and manage IP configuration.

o Example: ipconfig /renew to renew DHCP

leases.

5. netsh: Configure and manage network settings.

o Example: netsh wlan show profiles.

6. arp: Display or modify the ARP table.

o Example: arp -a to view the cache.

3. DNS and Name Resolution

7. nslookup: Query DNS for name-to-IP or IP-to-name

resolution.
 o Example: nslookup example.com.

8. ipconfig /displaydns: Show DNS resolver cache.

9. flushdns: Clear the DNS cache to resolve DNS

issues.

4. Active Connections and Traffic

10. netstat: Monitor active network connections

and ports.

o Example: netstat -an.

11. tasklist + netstat: Combine to identify

processes using specific ports.

o Example: netstat -ano | findstr :80.

5. File and Resource Sharing

12. net use: Map network drives or shared

resources.

o Example: net use Z: \\server\share.

13. net view: Display shared resources on a

network.

o Example: net view \\server.

6. Troubleshooting Tools

14. telnet: Test connectivity to a specific port.

o Example: telnet 192.168.1.1 22.

15. pathping: Diagnose latency and packet loss

along a route.
 16. ncpa.cpl: Open the network connections GUI
for adapter settings.

7. Advanced Commands

17. route: View or modify the system’s routing

table.

o Example: route print.

18. getmac: Retrieve the MAC addresses of

network adapters.

o Example: getmac.

19. nbtstat: Troubleshoot NetBIOS name

resolution.

o Example: nbtstat -n.

8. Remote Management

20. mstsc: Open Remote Desktop Connection.

o Example: mstsc /v:192.168.1.10.

Practice Routine

 Daily Tasks: Regularly test connectivity (ping),

monitor network connections (netstat), and review
DNS behavior (nslookup).

 Office Use: Map drives (net use), monitor active

ports, and configure adapters (ncpa.cpl).

 Troubleshooting: Resolve issues with ipconfig,

arp, route, and flushdns.

Additional Tips
  Documentation: Keep notes on command outputs
for future reference.

 Hands-On: Simulate network scenarios on virtual

environments like VMware or GNS3.

 Learning Tools: Familiarize yourself with

Wireshark and Cisco Packet Tracer.

Let me know if you need more focused guidance, such

as practice exercises or troubleshooting workflows!

Here’s a comprehensive guide

to network cables, their types,
categories, uses, and other
essential details:
1. Twisted Pair Cables
Overview:
Twisted pair cables are the most common in networking and consist
of pairs of wires twisted together to reduce electromagnetic
interference (EMI).
Types:
1. Shielded Twisted Pair (STP):
o Shielding: Additional metal foil or braid to reduce EMI.
o Use: Industrial environments or areas with high
interference.
2. Unshielded Twisted Pair (UTP):
o No shielding: Relies on twisting to minimize interference.
o Use: Office and home networks (common in Ethernet).
Categories (Commonly used for Ethernet networks):
 Cat 3: 10 Mbps, 16 MHz (Used in old telephone systems and
10Base-T Ethernet).
 Cat 5: 100 Mbps, 100 MHz (Obsolete, replaced by Cat 5e).
 Cat 5e (Enhanced): 1 Gbps, 100 MHz (Minimized crosstalk;
common for Gigabit Ethernet).
 Cat 6: 1 Gbps (up to 55m), 250 MHz (Improved performance;
used for higher-speed networks).
 Cat 6a (Augmented): 10 Gbps, 500 MHz (Reduced interference,
suitable for longer distances).
 Cat 7: 10 Gbps, 600 MHz (Shielded, better for high-performance
networks).
 Cat 8: 25-40 Gbps, 2 GHz (Designed for data centers).
Connectors:
 RJ45: Standard connector for Ethernet cables.
2. Coaxial Cables
Overview:
Single copper conductor surrounded by insulation, shielding, and an
outer plastic cover.
Types:
1. Thick Coaxial (RG-8): Used in backbone cabling.
2. Thin Coaxial (RG-58): Used in older Ethernet networks.
3. RG-6: Common in cable TV and broadband Internet.
Uses:
 Cable TV connections.
 Broadband internet.
 Legacy Ethernet (10Base2, 10Base5).

3. Fiber Optic Cables

Overview:
Uses light to transmit data, offering high speeds and long-distance
transmission.
Types:
1. Single-Mode Fiber (SMF):
o Core Diameter: Smaller (8-10 µm).
o Use: Long-distance transmission (e.g., telecom networks).
2. Multi-Mode Fiber (MMF):
o Core Diameter: Larger (50-62.5 µm).
o Use: Shorter distances (e.g., LANs, data centers).
Connectors:
 SC: Square-shaped, easy to plug/unplug.
 LC: Smaller, used in high-density connections.
 ST: Round, bayonet-style.
 MTP/MPO: Multi-fiber connectors.
Advantages:
 High bandwidth.
 Immunity to electromagnetic interference.
 Long-distance transmission.

4. Ethernet Cables
Overview:
Ethernet cables are primarily twisted-pair cables (UTP or STP) and are
categorized based on speed and performance.
Common Types:
 Cat 5e: Standard for basic Gigabit Ethernet.
 Cat 6/6a: For faster and more reliable connections.
 Cat 7/8: For high-speed connections in advanced networks.
Usage:
 LAN and WAN connections.
 Device interconnections like PCs, routers, switches.

5. Serial and Parallel Cables

Overview:
Used for older networking standards and point-to-point connections.
Types:
1. RS-232 Serial Cables:
o Used for connecting modems and legacy network devices.
2. Parallel Cables:
o Used for printer connections and some older data
transmission.

6. Crossover and Straight-Through Cables

1. Straight-Through Cable:
o Pins are mapped directly from one connector to another.
o Use: Connecting different types of devices (e.g., PC to
switch).
2. Crossover Cable:
o Wires are crossed (Tx to Rx).
o Use: Connecting similar devices (e.g., PC to PC).

7. Patch Cables
 Overview: Short cables for interconnecting devices within a
rack or patch panel.
 Use: Switch to router, patch panel to network device.

8. USB Cables
 Use in Networking:
o Connecting USB modems.
o Tethering internet via mobile devices.
Cable Selection Tips:
1. Speed and Bandwidth: Choose cables supporting the desired
data rate (e.g., Cat 6a for 10 Gbps).
2. Environment: Use shielded cables in high-interference areas.
3. Distance: Opt for fiber optic cables for long-distance
communication.
4. Cost: Balance performance and budget (e.g., Cat 5e is cost-
effective for most LANs).
Let me know if you want specific scenarios or a deeper dive into a
particular type of cable!

Subnetting Table for 192.168.5.15

Host
CIDR Total
Subnet s per Network Broadcas First Last
Nota Subn
Mask Sub ID t ID Usable IP Usable IP
tion ets
net
255.255.25 192.168. 192.168. 192.168. 192.168.
/24 1 254
5.0 5.0 5.255 5.1 5.254
255.255.25 192.168. 192.168. 192.168. 192.168.
/25 2 126
5.128 5.0 5.127 5.1 5.126
192.168. 192.168. 192.168. 192.168.
5.128 5.255 5.129 5.254
255.255.25 192.168. 192.168. 192.168. 192.168.
/26 4 62
5.192 5.0 5.63 5.1 5.62
192.168. 192.168. 192.168. 192.168.
 Host
CIDR Total
Subnet s per Network Broadcas First Last
Nota Subn
Mask Sub ID t ID Usable IP Usable IP
tion ets
net
5.64 5.127 5.65 5.126
192.168. 192.168. 192.168. 192.168.
5.128 5.191 5.129 5.190
192.168. 192.168. 192.168. 192.168.
5.192 5.255 5.193 5.254
255.255.25 192.168. 192.168. 192.168. 192.168.
/27 8 30
5.224 5.0 5.31 5.1 5.30
192.168. 192.168. 192.168. 192.168.
5.32 5.63 5.33 5.62
192.168. 192.168. 192.168. 192.168.
5.64 5.95 5.65 5.94
... ... ... ...
255.255.25 192.168. 192.168. 192.168. 192.168.
/28 16 14
5.240 5.0 5.15 5.1 5.14
192.168. 192.168. 192.168. 192.168.
5.16 5.31 5.17 5.30
192.168. 192.168. 192.168. 192.168.
5.32 5.47 5.33 5.46
... ... ... ...
255.255.25 192.168. 192.168. 192.168. 192.168.
/29 32 6
5.248 5.0 5.7 5.1 5.6
192.168. 192.168. 192.168. 192.168.
5.8 5.15 5.9 5.14
 Host
CIDR Total
Subnet s per Network Broadcas First Last
Nota Subn
Mask Sub ID t ID Usable IP Usable IP
tion ets
net
... ... ... ...
255.255.25 192.168. 192.168. 192.168. 192.168.
/30 64 2
5.252 5.0 5.3 5.1 5.2
192.168. 192.168. 192.168. 192.168.
5.4 5.7 5.5 5.6
... ... ... ...

Explanation of Columns
 Subnet Mask: The subnet mask being used.
 CIDR Notation: Short notation for subnet masks (e.g., /24).
 Total Subnets: Number of subnets created by the mask.
 Hosts per Subnet: Usable IPs in each subnet (2 addresses
reserved for NID and BID).
 Network ID: Starting IP of the subnet.
 Broadcast ID: Last IP in the subnet (used for broadcasting).
 First Usable IP: First usable host IP.
 Last Usable IP: Last usable host IP.
Would you like a more detailed table for a specific subnet mask or
subnet design scenario?
RIP, OSPF, and EIGRP are dynamic routing protocols used in computer
networks to determine the best path for data packets. Here’s a
comparison highlighting their differences:

1. RIP (Routing Information Protocol)

 Type: Distance Vector Protocol.
 Metric: Hop count (maximum of 15 hops; 16 is considered
unreachable).
 Updates: Periodic updates every 30 seconds.
 Convergence: Slow due to periodic updates and limited
scalability.
 Usage: Suitable for small networks due to its simplicity.
 Routing Algorithm: Bellman-Ford Algorithm.
 Standard: Open standard; defined in RFC 1058 (RIP v1) and RFC
2453 (RIP v2).

2. OSPF (Open Shortest Path First)

  Type: Link-State Protocol.
 Metric: Cost (based on bandwidth; higher bandwidth links have
lower costs).
 Updates: Triggered updates (when there’s a topology change).
 Convergence: Faster than RIP due to link-state advertisements.
 Usage: Suitable for large and complex networks; widely used in
enterprise environments.
 Routing Algorithm: Dijkstra’s Shortest Path First (SPF)
Algorithm.
 Standard: Open standard; defined in RFC 2328 for OSPFv2
(IPv4) and RFC 5340 for OSPFv3 (IPv6).

3. EIGRP (Enhanced Interior Gateway Routing Protocol)

 Type: Hybrid Protocol (features of both distance vector and link-
state protocols).
 Metric: Composite metric (bandwidth, delay, load, and
reliability).
 Updates: Triggered updates, reducing unnecessary traffic.
 Convergence: Faster than both RIP and OSPF due to the
Diffusing Update Algorithm (DUAL).
 Usage: Ideal for medium to large networks; Cisco-proprietary
(though partially open since 2013).
 Routing Algorithm: DUAL (Diffusing Update Algorithm).
 Standard: Proprietary to Cisco (RFC 7868 partially documents
EIGRP).

Key Differences
Feature RIP OSPF EIGRP
Distance
Protocol Type Link-State Hybrid
Vector
Cost
Metric Hop count Composite metric
(bandwidth)
Convergence
Slow Fast Very Fast
Speed
Small Medium to large
Scalability Large networks
networks networks
Updates Periodic Triggered Triggered
Open
Proprietary Open Standard Cisco Proprietary
Standard
Algorithm Bellman-Ford Dijkstra's SPF DUAL

When to Use
 RIP: Small, simple networks with low scalability needs.
 OSPF: Large, enterprise-scale networks requiring robust routing
and fast convergence.
 EIGRP: Cisco-dominated networks where simplicity and speed
are crucial.
Would you like to explore configuration examples for any of these
protocols?
Here's a categorized list of commonly used network protocols across different layers of the OSI
model:

Application Layer Protocols

1. HTTP (HyperText Transfer Protocol): Web browsing.

2. HTTPS (HTTP Secure): Secure web browsing.

3. FTP (File Transfer Protocol): File transfers.

4. SFTP (Secure File Transfer Protocol): Secure file transfers.

5. SMTP (Simple Mail Transfer Protocol): Sending emails.

6. IMAP (Internet Message Access Protocol): Accessing emails.

7. POP3 (Post Office Protocol v3): Retrieving emails.

8. DNS (Domain Name System): Resolving domain names to IP addresses.

9. DHCP (Dynamic Host Configuration Protocol): Assigning dynamic IP addresses.

10. SNMP (Simple Network Management Protocol): Network device management.

11. Telnet: Remote access to devices (not secure).

12. SSH (Secure Shell): Secure remote access.

13. NTP (Network Time Protocol): Synchronizing clocks.

14. LDAP (Lightweight Directory Access Protocol): Directory services.

15. RDP (Remote Desktop Protocol): Remote desktop access.

16. MQTT (Message Queuing Telemetry Transport): IoT and lightweight messaging.

17. SIP (Session Initiation Protocol): VoIP signaling.

Presentation Layer Protocols

1. SSL/TLS (Secure Sockets Layer/Transport Layer Security): Encrypting communications.

2. JPEG/GIF/PNG: Image formats.

3. MPEG/MP4: Video formats.

 4. ASCII/UTF-8: Text encoding.

Session Layer Protocols

1. NetBIOS (Network Basic Input/Output System): Application session communication.

2. RPC (Remote Procedure Call): Calling processes remotely.

Transport Layer Protocols

1. TCP (Transmission Control Protocol): Reliable, connection-oriented communication.

2. UDP (User Datagram Protocol): Fast, connectionless communication.

Network Layer Protocols

1. IP (Internet Protocol): Addressing and routing (IPv4, IPv6).

2. ICMP (Internet Control Message Protocol): Network diagnostics (e.g., ping).

3. IGMP (Internet Group Management Protocol): Multicasting.

4. BGP (Border Gateway Protocol): Internet routing.

5. OSPF (Open Shortest Path First): Interior routing within an autonomous system.

6. EIGRP (Enhanced Interior Gateway Routing Protocol): Cisco proprietary routing protocol.

Data Link Layer Protocols

1. Ethernet (IEEE 802.3): Wired local area networking.

2. Wi-Fi (IEEE 802.11): Wireless networking.

3. PPP (Point-to-Point Protocol): Direct connection between two nodes.

4. HDLC (High-Level Data Link Control): WAN connections.

5. ARP (Address Resolution Protocol): Mapping IP addresses to MAC addresses.

6. RARP (Reverse ARP): Mapping MAC addresses to IP addresses.

Physical Layer Protocols

1. RS-232: Serial communication.

2. USB: Universal Serial Bus for devices.

3. DSL (Digital Subscriber Line): Internet over phone lines.

4. 802.3: Ethernet for physical transmission standards.

Security Protocols (Spanning Layers)

1. IPSec (Internet Protocol Security): Secure communication over IP.

2. Kerberos: Authentication protocol.

3. PPTP (Point-to-Point Tunneling Protocol): VPN implementation.

4. L2TP (Layer 2 Tunneling Protocol): Secure VPN tunneling.

5. OpenVPN: Open-source VPN solution.

Let me know if you need detailed explanations or use cases for any specific protocol!