Journal 1
Understanding Modern Network Components and Connectivity
Modern networks rely on three primary types of media to interconnect devices, each with distinct methods of data transmission:
Metal Wires within Cables: Data is encoded into electrical impulses, making it possible to transmit information over copper cables, such as Ethernet cables.
Glass or Plastic Fibers within Cables (Fiber-Optic Cable): Data is encoded into pulses of light, allowing for high-speed transmission over long distances with minimal signal loss. Fiber-optic cables are crucial for modern high-speed networks.
Wireless Transmission: Data is encoded via modulation of specific frequencies of electromagnetic waves, enabling wireless communication between devices such as smartphones, tablets, and laptops.
End Devices in a network include printers, wireless tablets, and desktop computers, which directly interface with users. Intermediary Devices such as switches, routers, and firewall appliances manage and direct data traffic within and between networks.
Local Area Networks (LANs) provide network access to users and devices within a small geographical area, like a department within a company or a home network. Wide Area Networks (WANs), on the other hand, connect multiple LANs over large distances and are typically managed by large organizations or telecommunications providers.
Intranets refer to private networks that connect multiple LANs and WANs within an organization, accessible only to authorized members. In contrast, Extranets allow secure access to an organization's data for external parties, such as partners or vendors, who require controlled access to certain resources.
Journal 2
Hands-On Network Switch Configuration: Enhancing Security and Connectivity
Last week, I gained valuable hands-on experience with network switch setup and configuration using Cisco commands. The process began with plugging in the console cable and connecting it to my computer. I then used PuTTY to access the command line interface of the switch.
Once connected, we entered enable mode to access privileged commands. The first task was to set up a secure password to protect access to the switch's configuration, ensuring that only authorized users could make changes.
We then changed the hostname of the switch, which aids in identifying different devices within the network environment. Adding IP addresses to the switch was another crucial step, enabling it to communicate with other devices on the network.
Finally, I practiced using SSH to securely connect to the switch remotely and tested connectivity by pinging other devices on the network. This exercise enhanced my understanding of network security, device management, and remote troubleshooting in real-world scenarios.
Journal 3
Exploring Network Fundamentals: Protocol Suites, Open Standards, and the Physical Layer
This week, I explored Modules 3 and 4, which deepened my understanding of how the internet functions through the use of protocols and models. Module 3 introduced me to the concept of protocol suites, particularly focusing on the TCP/IP model, which is fundamental to the structure of the internet. Protocol suites, like TCP/IP, are collections of protocols that work together to ensure that data can travel efficiently between devices across different networks. Each protocol has a specific function, but together, they create a seamless process for sending and receiving data.
I also learned about open standards, which are essential in ensuring that different systems and devices can communicate, regardless of the manufacturer or operating system. Open standards, such as those defined by the Internet Engineering Task Force (IETF), allow for widespread compatibility and innovation. These standards ensure that the internet remains accessible to everyone, making it easier for systems to interconnect and exchange information.
A key takeaway from Module 3 was the concept of data encapsulation, which is the process by which data is packaged into smaller units as it moves through the layers of the TCP/IP model. Each layer application, transport, internet, and network access adds its own header to the data, ensuring that it reaches its destination properly. This structured approach enables different devices and networks to communicate effectively, regardless of differences in their hardware or software.
Module 4 focused on the physical layer, which is responsible for the actual connection of devices through hardware like cables, switches, and routers. I learned about different types of cables, including twisted pair, coaxial, and fiber optic, and how each plays a role in the reliability and speed of data transmission. The physical layer is the foundation of network communication, and understanding how cabling and other hardware components function helps me appreciate how the entire network system is built.
This week’s learning showed me how protocol suites and open standards make global communication possible, while the physical layer provides the infrastructure that connects everything together.
Journal 4
Mastering VLANs for Network Segmentation and Security
In today's study session, I gained a deeper understanding of Virtual Local Area Networks (VLANs) and their critical role in network segmentation at the data link layer (Layer 2). VLANs are invaluable for creating isolated broadcast domains, significantly reducing network traffic by confining broadcast traffic, such as ARP requests, within specific segments. This capability enhances both network performance and security.
Efficient Network Segmentation:
VLANs enable multiple networks to coexist on a single physical switch, eliminating the need for additional hardware. This logical separation is not only cost-effective but also simplifies network management. Routers facilitate inter-VLAN communication by removing the VLAN ID during packet routing.
Avoid VLAN 1:
By default, switches come pre-configured with VLAN 1, but best practices dictate creating additional VLANs for specific departments (e.g., HR, IT) to enhance security.
I practiced configuring VLANs with the following steps:
Enter global configuration mode: conf t
Create a new VLAN: vlan 10
Assign a name: name HR 3
Configure interface range and access mode:
interface range f0/2-10
switchport mode access
Assign ports to the VLAN: switchport access vlan 10
Save the configuration: write memory
Using the show vlan command, I verified the VLAN setup and checked port assignments, which provided insights into how traffic was segmented.
To mitigate risks associated with unused ports, I practiced creating a "Black Hole" VLAN (VLAN 51). The steps included:
Assigning unused ports to VLAN 51.
Shutting down these ports to prevent unauthorized access.
This practice ensures that inactive ports remain secure unless explicitly needed.
For troubleshooting and identifying the VLAN a PC is connected to, I used:
SSH to access the switch and run the show vlan command.
Tools like Wireshark and Cisco Discovery Protocol for advanced network insights.
Today’s practice reinforced the importance of VLANs in achieving efficient traffic management and robust security. By mastering these configurations, I am better equipped to design and maintain segmented networks that safeguard sensitive data and optimize resource utilization.
Journal 5
Step-by-Step Guide: Configuring EIGRP and OSPF in a Network
EIGRP (Enhanced Interior Gateway Routing Protocol) Setup
Step 1: Access the router via the command line
Enter privileged mode by typing:
en
Enter global configuration mode:
conf t
Step 2: Assign IP addresses to each router interface and bring them up:
Int g0/0
Ip address 192.168.1.1 255.255.255.0
No shut
Step 3: Enable EIGRP
Start the EIGRP routing process:
Router eigrp #
Step 4: Advertise Networks
Specify which networks to include in EIGRP:
Network 192.168.1.0 0.0.0.255
Step 5: Check EIGRP neighbors:
Show ip eigrp neighbors
View the routing table:
Show ip route
OSPF (Open Shortest Path First) Setup
Step 1 Access the router via CLI.
Enter privileged mode:
en
Enter global configuration mode:
Conf t
Step 2: Assign IP Addresses to Interfaces
Assign IP addresses to each router interface and bring them up:
Int go/o
Ip address 192.168.1.1 255.255.255.0
No shut
Step 3: Enable OSPF
Start the OSPF process:
Router ospf #
Step 4: Define OSPF Networks and Areas
Specify networks and their respective OSPF areas:
Network 192.168.1.0 0.0.0.255 area 0
Step 5: Verify the Configuration
Check OSPF neighbors:
Show ip ospf neighbor
View the routing table:
Show ip route
EIGRP
Enhanced Interior Gateway Routing Protocol (EIGRP) is a distance-vector routing protocol developed by Cisco. It uses metrics like bandwidth, delay, load, and reliability to calculate the best path for data. EIGRP is easy to configure and is efficient in managing large, Cisco-based networks.
OSPF
Open Shortest Path First (OSPF) is a link-state routing protocol. It uses a hierarchical structure and calculates the shortest path using Dijkstra’s algorithm. OSPF is vendor-neutral, scalable, and ideal for large enterprise networks.
Dynamic Routing: Both protocols automatically learn and adapt to changes in the network topology, reducing the need for manual configurations.
Fault Tolerance: If a link fails, EIGRP and OSPF quickly recalculate paths, ensuring minimal downtime.
Efficient Use of Resources: They optimize traffic flow across the network, ensuring efficient data transmission.
Scalability: These protocols support large, complex networks, with OSPF excelling in multi-vendor environments and EIGRP performing well in Cisco-exclusive setups.
Journal 6
Exploring IT Careers and Network Essentials
This week, we explored various careers in IT, including IT Support Specialist, Software Engineer, and senior-level roles. IT Support Specialists are often the first point of contact for troubleshooting technical issues, requiring strong problem-solving skills and excellent customer service. Software Engineers focus on designing, developing, and maintaining software solutions. Senior IT positions usually require both technical proficiency and leadership experience, as they often involve managing teams, overseeing projects, and making strategic decisions. In addition to career discussions, we covered information about Network Interface Cards (NICs) and how they relate to MAC addresses. NICs are hardware components that connect computers to networks, enabling communication between devices. Each NIC has a unique Media Access Control (MAC) address, which serves as a hardware identifier for network communication. Understanding how NICs and MAC addresses function is essential for network configuration and security, as they play a crucial role in data transmission and device identification within a network.