3. Repeater
Attenuation – degeneration of a signal
Cleans up the signal
Extends the distance of the network
Repeaters are for digital transmissions
Optical repeaters for fiber optics
Amplifiers are for analog transmissions
Layer 1 component
5. Hub
Central wired access point
Broadcasts all data to all other devices
(everything that goes in comes back out)
Shared medium (contention)
Layer 1 component
Passive Hub
Does not regenerate the signal
Does not have to be powered
Active Hub
Regenerates the signal
Must be powered
Multi-port repeater
6. WAPs (Wireless Access
Points)
Wireless clients connect through
specified channels within an
electromagnetic frequency
Layer 1 device
Contention
Speeds get slower the further away you
are from the AP (Access Point)
Other objects may cause interference
7. Ethernet
CSMA/CD (Carrier Sense Multiple
Access Collision Detection)
Collisions cause nodes to enter into a
backoff state where they do not transmit
8. Bridge
Analyzes layer 2 addresses
Makes forwarding decisions
Broadcast frames are always forwarded
Segments the collision domain
Layer 2 device
Transparent Bridge - Keeps a bridging table
for each side
Source-Routing Bridge – The source host
provides info on how to reach the destination
host. (Used on Token Ring networks)
Translation Bridges – connect two different
networks
9. Switch
Multi-port Bridge
Layer 2 device
Creates a bridging table for all ports
Microsegmentation – creating a virtual
circuit between two ports.
Each port receives the full bandwidth
Reduces the collision domain
Higher security against sniffers (also
harder to do network diagnostics)
10. Routers
Connects internetworks and diverse segments
Layer 3 device
Looks at logical addresses to make a routing
decision
Exchanges routing information with other
routers using routing protocols
Segments the broadcast domain because
broadcasts are not routed
Slower than lower network devices
Can filter packets based on ACLs (Access
Control Lists)
11. Other Devices
Brouter / Layer 3 Switch
Works with frames for nonroutable protocols
and packets for routable protocols
Can route between VLANs (Virtual LANs)
Faster in some cases than a router
Gateway
Can translate between different protocols
suites all the way to the application layer
12. Acronyms
ACL, Access Control List
AP, Access Point
CSMA/CD, Carrier Sense Multiple
Access Collision Detection
VLAN, Virtual LAN
WAP, Wireless Access Point