Lesson 3: Deploying Ethernet Switching Flashcards
How would someone physically limit attenuation of and distance limitation of cabling?
A layer 1 repeater overcomes distance limitations of cables by boosting the signal wherever the device is placed; connects two cable segments of the same type
What is a media converter?
A layer 1 device used to transition from one cable type to a different cable type
List the typical media conversions
- Single mode fiber to twisted pair
- Multimode fiber to twisted pair
- Single mode to multimode fiber
How do hubs operate?
At the physical layer, hubs act as multiport repeaters so that every port receives transmissions sent from any other port
What limits do hubs present?
- Each hub port is part of the same collision domain
- All node interfaces are half duplex
- The bandwidth is shared between all nodes in the segment (up to 100mbps)
What interface technology is used to distinguish transmit and receive wires/pins on different interfaces?
Nodes have a medium dependent interface (MDI) while hubs have a MDI crossover (MDI-X) interface, allowing transmit wires on the host connect to the receive wires on the hub
Define an Ethernet bridge
Layer 2 device that isolates collision domains to separate segments while joining segments within the same broadcast domain allowing nodes in the separate segments to communicate
Define micro-segmentation in layer 2 switching
Each switch port is it’s own collision domain, essentially establishing a point to point link between any two network nodes
How does a collision occur in a switched network
It would only occur if the port is operating in half duplex mode due to a legacy network card or hub is attached to the switch, and even then the collision would only occur in that individual microsegment
What’s the purpose of a Network Interface Card (NIC)?
Physically connects the transceiver component to the transmission medium
How are NICs identified?
Each NIC port has a unique hardware address known as the Media Access Control (MAC) address, also known as and extended unique identifier (EUI), and local/physical address
What is the PDU in layer 2 Ethernet called?
A Frame
What makes up an Ethernet frame?
- Preamble
- SFD
- Destination and Source MAC
- Ether Type
- Payload
- FCS (Frame check sequence)
What functions do the preamble and SFD perform in an Ethernet frame?
The preamble and SFD are used for clock synchronization and as part of CSMA/CD to identify collisions early
What is the function of FCS?
Frame Check Sequence (FCS) is used to verify the integrity of the frame; the sending node calculates contents of the frame, and the receiving node does the same, if the calculations match, the receiving node accepts the frame
Define a Burned-in Address
In a MAC/EUI, this is first six hex digits that are assigned to a manufacturer by the IEE
What term defines the max size of a data payload?
Maximum Transmission Unit (MTU)
What is the max size of a data payload and what is the max size of an Ethernet frame?
- The max size of a data payload is 1500 bytes
- The max size of an Ethernet frame is 1518 bytes, excluding the preamble