Understanding Network Switches, IP Addressing, and Key Terms

Network Switches

Managed vs. Unmanaged Switches

Managed Switch: Configurable via software, supports security and communication settings. Used in large networks (enterprise, universities).

Unmanaged Switch: Fixed configuration, hardware-only, cannot be configured.

Ethernet & Speed

1. Fast Ethernet: 100 Mbps.
2. Gigabit Ethernet: 1 Gbps.

Ethernet Protocol

Divides data into frames, encapsulates IP addresses, performs error detection.

Ports

3. Console Port: Connects PC/laptop to configure switch.

Communication Modes

• Simplex (Half Duplex): One-way communication at a time.
• Duplex (Full Duplex): Two-way communication simultaneously.

Bandwidth

5. Maximum transmission speed of a network, determined by signal frequency range.

IP Addressing & Subnets

6. IP Address: Identifies device on network.
7. Subnet Mask (32-bit): Determines network portion of IP.
   • Same network → send directly to device.
   • Different network → send via default gateway.
8. Network Address: IP & subnet mask combined.
   • Example: IP: 172.20.0.2, Subnet: 255.255.0.0 → Network: 172.20.0.0, Range: 172.20.0.0 – 172.20.255.255
9. Default Gateway: First usable address after network address (router interface).

DNS (Domain Name System)

7. Converts hostnames → IP addresses.
8. Easier to remember device names than IPs.

MAC Address (Media Access Control)

8. 48-bit unique address, burned into NIC.
9. Ensures uniqueness across devices.
10. MAC Notations:
    1. Cisco: XXXX.XXXX.XXXX
    2. Byte-dash: XX-XX-XX-XX-XX-XX
    3. Byte-colon: XX:XX:XX:XX:XX:XX
11. Conversion: Binary ↔ Hexadecimal.

Conversions

9. Binary ↔ Dotted Decimal (for IP addresses)
10. Binary ↔ Hexadecimal (for MAC addresses)
11. Must convert both ways.

Ping Command

10. ping → Test connectivity & latency.
    • Windows → 4 packets by default.
    • Mac/Linux → Sends continuously until stopped.
11. Outputs:
    • Connectivity: Is host reachable?
    • Latency: Round-trip time for packet.
    • TTL (Time To Live): Prevents endless packet loops.

Key Terms

11. Latency/Delay: Time from sending request → receiving reply.
12. Bandwidth: Max network speed.
13. TTL: Limits lifespan of packets to avoid network congestion.
14. Simplex: One-way. Duplex: Two-way.

Extra Tips for Exam

• First usable IP = default gateway.
• Always check subnet mask to determine if destination is in same network.
• MAC addresses are unique & permanent.
• Ping average time = network delay/latency.