Network Devices
Router: Connects multiple networks, directing data packets between them. It manages traffic and provides access to the internet.
Switch: Connects devices within a single network, using MAC addresses to forward data to the correct destination. It operates at the data link layer (Layer 2).
Hub: A basic networking device that connects multiple Ethernet devices, making them act as a single network segment. It broadcasts data to all ports, which can lead to collisions.
Access Point (AP): Extends a wired network by adding Wi-Fi capability, allowing wireless devices to connect to the network.
Firewall: Monitors and controls incoming and outgoing network traffic based on predetermined security rules. It can be hardware-based or software-based.
Modem: Modulates and demodulates signals for data transmission over telephone lines, cable systems, or satellite connections, enabling internet access.
Network Interface Card (NIC): A hardware component that allows devices to connect to a network, either wired (Ethernet) or wireless (Wi-Fi).
Repeater: Amplifies and regenerates signals in a network to extend the transmission distance, commonly used in long-distance connections.
Bridge: Connects two or more network segments, filtering traffic and reducing collisions by dividing traffic into separate collision domains.
Gateway: Acts as a "gate" between two networks, often with different protocols, enabling communication and data transfer between them.
Hub vs. Switch vs. Router
Category
Hub
Switch
Router
Layer
Physical layer (L1)
Data link layer (L2)
Network layer (L3)
Function
Blindly broadcasts to all ports
Forwards frames based on MAC addresses/VLAN
Routes packets based on IP addresses (supports NAT/VPN/WiFi AP)
Data Stored
None
MAC address table (maps MAC to ports)
IP routing table (subnet routes)
Traffic Changes
None
None
Modifies TTL & checksum in IPv4 header
Broadcast Domain
Single broadcast domain
One per VLAN
Separate domain per interface
Ports
4/12 ports
4–48 ports
2/4/5/8 ports
Delivery
Bits
Frames
Packets
Duplex Mode
Half duplex
Half/Full duplex
Full duplex
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