Which osi layer is responsible for node to node delivery and putting data into frames
Data link layer
Primary devices that operate at layer 2
Switches and bridges
What is the pdu (data unit) at layer 2 called
Frame
What two addressing types are inside every layer 2 frame
Source MAC address Plus destination MAC address
What is the name of the error detection field at the end of a layer 2 frame
FCS (frame check sequence) - calculated using CRC (cyclic redundancy check)
Switch versus hub at layer 2 - main functional difference
Switch= learns Mac addresses and forwards only to correct Port , hub = dumb flooding to all ports
Why do switches reduce collisions compared to hubs
Switches create separate collision domains per port (micro-segmentation)
Main advantages of a switch over a hub
More efficient + more secure (less sniffing)
What is the main job of a bridge
Connects two or more network segments and filters traffic using MAC addresses
Are switches and bridges the same thing today
Yes - modern switches are multi port bridges
What hardware and every computer handles layer 1 and layer 2
NIC
What you need to identifier does it every network interface card have burned in
MAC address (48 bit hardware addresses)
NICS operates at which 2 osi layers
Layer 1 ( physical transmission) and layer 2 (framing & MAC addressing )
Where is the CRC value located in a frame
In the FCS field at the end of the frame
What happens if the CRC/FCS check fails at the receiver
Frame is dropped (silent discard)
Switch/bridge decision is based on which address
Destination MAC address
A hub is a multiport ____?
Repeater
What happens when a switch first receives a frame with an unknown destination MAC
It floods the frame out to all ports except the source Port(same behavior as a hub until it learns )
What is the switchest Mac address table also called
Cam table( content addressable memory)
