Related Topics
- Network Topologies
- Types of Cables
- Ethernet Standard
- Devices
NOTE
- In the OSI Model and 5 Layer TCP/IP Model, Ethernet Protocol belongs in both the Physical Layer (Layer 1) & Data Link Layer (Layer 2)
- Layer 1 Ethernet contains the Physical Aspects (Cables) and Layer 2 Ethernet deals with the Logical Aspects (Protocols)
Communication Synchronization
Asynchronous Communication
Data is send when the receiver is not present/ active
e.g. Sending a Voicemail
Start and stop bits are used to indicate the start and end of the transmission to the receiver
Synchronous Communication
Uses a reference clock to coordinate the transmission between the sender and receiver
Bandwidth Utilization
Bandwidth: Measures the theoretical data transfer capacity
Throughput: Measures the actual data transfer capacity
Broadband
Divides bandwidth into separate channels
TV channels - we choose the portion of the bandwidth (channel) we what to use
Baseband
Uses all available frequencies on the medium (cable) to transmit data
Telephone - uses the entire network bandwidth (1 call at a time)
Ethernet Cable - uses the entire bandwidth to transmit data
Baseband uses a reference clock (Synchronous Communication)
Network Multiplexing
Allows to simultaneously use baseband connection
Time-Division Multiplexing (TDM)
Each session takes a turn, using time slots, to share the medium between users
Time slots are assigned even if the user does not need it
Statical Time-Division Multiplexing (StatTDM)
Dynamically allocates the time slots on an as-needed basis
Frequency-Division Multiplexing (FDM)
Divides the medium into channels based on frequencies and each session is transmitted over a different channel
Transceivers
Converts media from one format to another
GBIC: Hot pluggable Ethernet transceiver than can take copper or fiber as its connector
| Transceiver | Speed |
|---|---|
| SFP (Small form-factor pluggable) | Up to 4.2 Gbps |
| SFP+ | Up to16 Gbps |
| QSFP (Quad Small form-factor pluggable) | Up to 40 Gbps |
| QSFP+ | Up to 41.2 Gbps |
| QSFP28 | Up to 100 Gbps |
| QSFP56 | Up to 200 Gbps |