Ethernet and Switching Flashcards
At which OSI layer does ethernet function
Data Link Layer (2)
What does CSMA/CD stand for
Carrier Sense Multiple Access with Collision Detection
Collision Domain
A group of networked devices that will simultaneously detect a voltage spike (when spike is detected all devices stop sending messages).
Half duplex communication
One device communicates at a time (walkie talkie).
Full duplex communication
Two devices communicate at the same time (telephone) collisions are not possible
Modern Collision domain
Half duplex communication between a device and a switch (most modern networks are full duplex).
Ethernet II Frame
Mechanism that we use to move data across and ethernet network from 1 device to another.
Data packet
A unit of data made into a package that travels along a given network path.
Frame
A chunk of data, with a data link layer header
Components of an Ethernet Header
Destination MAC address, Source MAC address, Type, FCS
Network interface card
The device that connects our PC to an ethernet cable
MAC address
Composed of Manufacturer ID and Serial Number. Layer 2 address/identifier specifically tied to a network interface card.
Ethernet Header Type Field
Tells us what type of data is being transferred
Ethernet FCS
Frame Check Sequence Cyclical Redundancy Check (CRC)
Protocol Data Unit
Varies from layer to layer. Entire Frame and Data (payload) that is being transferred
Bus Topology
Single wire (rarely seen)
Ring Topology
Device connections create a circular path (rarely seen)
Star Topology
Each device is connected to a layer 2 device
Ethernet switch
Used in wired networks to connect devices using Ethernet cables; allows connected devices to talk to other devices.
Mac Address Table
Used by a switch to keep track of port and mac addresses. Creates virtual circuits within the switch to eliminate collisions.
Layer 2 Broadcast message
When the destination MAC address of the frame is all F’s the frame is sent out to all active interfaces, except the receiving interface. (Don’t confuse this with layer 3 broadcast addresses that are rarely used).
Broadcast Domain
Group of networked devices which will receive a layer 2 broadcast message.
Physical addres
Same as a MAC address; sometimes called the hardware address