Ethernet Lan switching

Question 1

What are the five parts of a Frame header?

Answer 1

1. Preamble
2. SFD (Start Frame Delimiter)
3. Destination MAC
4. Source MAC
5. Type/Length

Question 2

Preamble

Answer 2

Synchronizes receiving clocks (so that other device is ready to receive the rest of the frame)

Question 3

SFD

Answer 3

Start Frame Delimiter, marks where the preamble ends and the rest of the frame starts

Question 4

Type/length

Answer 4

if less than 1500, its the length of the frame
if greater than 1536, it is the frame type (ie ipv4 = 0x0800)

Question 5

Frame trailer

Answer 5

Contains the FCS (Frame Check sequence) that checks for corrupted data by running CRC (Cyclic redundancy check)

Question 6

MAC address

Answer 6

unique address assigned to all devices. first three bytes are the OUI (assigned to company) and the last three bytes are unique values.

Question 7

What happens when a switch receives a known unicast frame?

Answer 7

Fills in the CAM table with the source MAC address from the frame and the interface that it came from

Question 8

What happens when a switch receives a unknown unicast frame destined for elsewhere?

Answer 8

Will flood frame to all other switches