Unit 2 test #3 networking

LAN Topologies

Star connects all devices to a central switch/hub, bus connects devices along a single shared cable, and mesh connects every device directly to every other device. Star is easiest in small workshops because it’s simple and easy to troubleshoot.

Role of a Switch vs. Hub

A switch connects devices in a LAN and forwards data only to the intended device using MAC addresses. A hub broadcasts to all devices on the network.

Copper vs. Fiber Cabling

Copper is cheaper and easier to install, ideal for small LANs. Fiber optic offers higher speeds and longer distance performance but costs more and is unnecessary for short local setups.

Ethernet Link Lights

They show whether there’s a physical connection and if data is being transmitted, helping identify cable or port issues during troubleshooting.

IPv4 Network vs. Host Portion

In an address with mask 255.255.255.0, the last octet (.0) represents the host portion, and the first three octets represent the network.

Duplicate IPv4 Addresses

Two devices using the same IP cause a conflict, resulting in intermittent or no connectivity.

Static IP Example

Used for devices that must always have the same address, like printers or servers.

Purpose of Subnet Mask

It identifies which part of an IP address represents the network and which part represents the host, helping devices decide if others are local or remote.

Testing LAN Connection with IPs

Compare network portions of IPs; if they match, they’re on the same LAN. Use the ping command to test communication.

Reason for IPv6

IPv6 was created to solve IPv4 address exhaustion and support the growing number of connected devices.

IPv6 “::” Symbol

Represents one group of consecutive zeroes in an IPv6 address. Example: fe80:0000:0000:0000:0000:0000:0000:0001 → fe80::1

IPv6 Address Compression

Removes leading zeros and groups of consecutive zeros (::) to make addresses shorter and easier to read.

IPv4 vs. IPv6 Automatic Addressing

IPv4 uses DHCP or static assignment, while IPv6 can self-configure using SLAAC (Stateless Address Autoconfiguration).

Troubleshooting Steps for LAN Connection

Check cables and link lights, verify correct IP configuration, and test connections by pinging devices.

Why Check Physical Cables First

Cable issues are the most common cause of connection problems and easiest to fix.

Ping Command

Tests connectivity between two devices by sending ICMP packets; useful for diagnosing physical or network layer issues.

Using Packet Tracer

Simulates a network for testing, visualizing data flow, and finding configuration or connection errors.

Transport Layer Problem Example

A TCP port mismatch can prevent communication even if the physical and network layers are working correctly.

Cat5 on Gigabit Networks

Cat5 cables can’t handle gigabit speeds due to lower frequency support, causing network bottlenecks or failures.

Attenuation

Signal strength weakens over distance, leading to slower transmission or loss. Caused by long cables or poor-quality materials.

Crosstalk

Interference between twisted pairs inside Ethernet cables caused by electrical signals. Minimized by proper twisting and shielding.

Cable Tester vs. Cable Toner

A cable tester checks for proper wiring and continuity; a toner helps trace and identify cables within a bundle.

Ethernet Length Limit

100 meters is the max recommended length for most copper Ethernet cables to prevent attenuation and signal loss.

192.168.1.5 vs. 192.168.2.5 Example

They can’t communicate directly because their network IDs are different with a 255.255.255.0 mask.

Documenting LAN Setup

Record IP addressing scheme, device names, cabling types, switch port connections, and configuration details.

Green Link Lights but No Communication

Indicates physical connection is working, but there may be configuration or addressing issues.

Long-Distance Connection Choice

Use fiber optic cabling for high-speed, long-distance links with minimal signal degradation.