Ethernet Frames and MAC Sublayer

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What is the primary function of the MAC sublayer?

To manage network topology

To provide physical layer technologies

To provide error detection

To encapsulate data and access media (correct)

What is the purpose of the frame check sequence (FCS) trailer in an Ethernet frame?

To provide source and destination MAC addresses

To ensure error-free transmission

To detect errors and correct them

To detect errors (correct)

What type of access method is used in half-duplex Ethernet?

Round-robin

Polling

Carrier sense multiple access/collision detection (CSMA/CD) (correct)

Token passing

What is the benefit of using switches in modern Ethernet LANs?

They do not require access control through CSMA/CD Signup and view all the answers

What is the purpose of the back-off algorithm in CSMA/CD?

To retransmit data Signup and view all the answers

What type of medium is used in legacy Ethernet?

Half-duplex Signup and view all the answers

What is the purpose of the source and destination MAC addresses in an Ethernet frame?

To deliver the Ethernet frame from one device to another Signup and view all the answers

What is the type of topology used in legacy Ethernet?

Bus topology Signup and view all the answers

What type of device will have an Ethernet NIC and a MAC address?

Any device that is the source or destination of an Ethernet frame Signup and view all the answers

What is the purpose of a unicast MAC address in Ethernet?

To send a frame from a single transmitting device to a single destination device Signup and view all the answers

What is the process used to determine the destination MAC address associated with an IPv4 address?

Address Resolution Protocol (ARP) Signup and view all the answers

What is the destination MAC address of an Ethernet broadcast frame?

FF-FF-FF-FF-FF-FF Signup and view all the answers

How does an Ethernet switch handle an Ethernet broadcast frame?

It floods the frame out all ports including the incoming port Signup and view all the answers

What happens to an Ethernet broadcast frame when it reaches a router?

It is not forwarded Signup and view all the answers

What is the significance of the destination IPv4 address in an Ethernet broadcast frame?

It has all ones in the host portion Signup and view all the answers

What is the purpose of the source MAC address in an Ethernet frame?

To identify the source device Signup and view all the answers

What does a switch use to make forwarding decisions?

MAC addresses Signup and view all the answers

What happens when a switch is turned on?

The MAC address table is empty Signup and view all the answers

What does a switch do when it receives a frame with a new source MAC address?

It adds the MAC address to the table Signup and view all the answers

What happens to an entry in the MAC address table after 5 minutes?

The entry is deleted Signup and view all the answers

What happens when a switch receives a frame with a source MAC address that exists in the table but on a different port?

The switch treats it as a new entry Signup and view all the answers

What does a switch do when it receives a frame with a unicast destination MAC address?

It looks for a match in its MAC address table Signup and view all the answers

What is the MAC address table also referred to as?

CAM table Signup and view all the answers

What is the purpose of the switch examining the source MAC address of the frame?

To learn new information Signup and view all the answers

What happens when a switch receives a frame with a destination MAC address that is not in its table?

The switch forwards the frame out all ports except the incoming port. Signup and view all the answers

How does a switch populate its MAC address table?

By examining the source MAC address of every frame. Signup and view all the answers

What is the advantage of store-and-forward switching?

It determines if a frame has errors before propagating the frame. Signup and view all the answers

How many forwarding methods are used by Cisco switches?

Two Signup and view all the answers

What happens when a switch receives a broadcast or multicast frame?

The switch forwards the frame out all ports except the incoming port. Signup and view all the answers

What is the minimum requirement for the cut-through switching method?

At least the destination address must be read. Signup and view all the answers

What happens when a switch's MAC address table contains the destination MAC address?

The switch forwards the frame out a single port. Signup and view all the answers

What is the purpose of computing the CRC in store-and-forward switching?

To determine if the frame has errors. Signup and view all the answers

What should be the configuration of autonegotiation on both sides of a link?

Both sides on Signup and view all the answers

What is the best practice for configuring Ethernet switch ports?

Configure them as full-duplex Signup and view all the answers

What type of connection requires a cross-over cable?

A connection between a router and a host Signup and view all the answers

What is the purpose of the auto-MDIX feature?

To automatically detect the type of cable attached to the port Signup and view all the answers

What should you always use when connecting devices?

The correct type of cable Signup and view all the answers

What is the default state of the auto-MDIX feature on switches running Cisco IOS Release 12.2(18)SE or later?

Enabled Signup and view all the answers

How can you re-enable the auto-MDIX feature?

Using the 'mdix auto' command Signup and view all the answers

What is the reason for not relying on the auto-MDIX feature?

It can be disabled Signup and view all the answers

What is the length of an Ethernet MAC address in bytes?

6 bytes Signup and view all the answers

What is the purpose of the organizationally unique identifier (OUI) in an Ethernet MAC address?

To identify the device's manufacturer Signup and view all the answers

What happens when a NIC receives an Ethernet frame with a destination MAC address that does not match its own?

The NIC discards the frame Signup and view all the answers

What type of MAC address is an Ethernet NIC configured to accept?

Unicast, broadcast, and multicast MAC addresses Signup and view all the answers

What is the significance of the source MAC address in an Ethernet frame?

It identifies the source device Signup and view all the answers

What is the purpose of the MAC address in an Ethernet LAN?

To provide device identification at the data link layer Signup and view all the answers

How many hexadecimal digits are used to express an Ethernet MAC address?

12 hexadecimal digits Signup and view all the answers

Why must all Ethernet devices have unique MAC addresses?

To ensure device identification at the data link layer Signup and view all the answers

What is the primary function of the LLC sublayer in Ethernet?

Communicating between the networking software and the device hardware Signup and view all the answers

What is the advantage of using Ethernet technology in LANs?

It supports bandwidths of up to 100 Gbps Signup and view all the answers

What is the purpose of the MAC sublayer in Ethernet?

Data encapsulation and media access control Signup and view all the answers

What is the main difference between Ethernet and WLANs?

Ethernet uses wired connections while WLANs use wireless connections Signup and view all the answers

What is the purpose of the Ethernet frame?

To encapsulate data for transmission over a network Signup and view all the answers

Which standard defines the Layer 2 protocols and Layer 1 technologies used in Ethernet?

IEEE 802.2 and 802.3 Signup and view all the answers

What is the primary function of the data link layer in Ethernet?

To encapsulate data for transmission over a network Signup and view all the answers

What is the advantage of using multiple Layer 3 protocols on the same network interface and media?

It enables the use of multiple Layer 3 protocols, such as IPv4 and IPv6 Signup and view all the answers

What does a switch do with the source MAC address of a frame when it is not in the MAC address table?

It adds the source MAC address to the table along with the incoming port number. Signup and view all the answers

What happens to an entry in the MAC address table if the source MAC address exists in the table but on a different port?

The entry is updated with the new port number. Signup and view all the answers

How does a switch make forwarding decisions?

Based on Layer 2 Ethernet MAC addresses Signup and view all the answers

What is the primary function of a switch in a network?

To filter out erroneous frames and forward them to the correct port Signup and view all the answers

What is the default time for which an entry stays in the MAC address table?

5 minutes Signup and view all the answers

What is the purpose of a switch examining the source MAC address of every frame?

To populate its MAC address table Signup and view all the answers

What does a switch do when it receives a frame with a unicast destination MAC address?

It looks for a match between the destination MAC address and an entry in its MAC address table. Signup and view all the answers

What happens when a switch receives a frame with a destination MAC address that is not in its table?

It forwards the frame out all ports except the incoming port Signup and view all the answers

What is the MAC address table also referred to as?

Content addressable memory (CAM) table Signup and view all the answers

How does a switch learn new MAC addresses?

By examining the source MAC address of incoming frames Signup and view all the answers

What is the advantage of using cut-through switching over store-and-forward switching?

It forwards the frame before it is entirely received Signup and view all the answers

What is the purpose of an unknown unicast in a switch?

To forward frames to all ports except the incoming port Signup and view all the answers

What happens when a switch receives a frame with a destination MAC address that is not in its table?

It broadcasts the frame to all ports. Signup and view all the answers

What is the difference between store-and-forward switching and cut-through switching?

Store-and-forward switching receives the entire frame before forwarding, while cut-through switching forwards the frame before it is entirely received Signup and view all the answers

What happens when a switch receives a frame with a broadcast or multicast destination MAC address?

It forwards the frame out all ports except the incoming port Signup and view all the answers

What is the benefit of using store-and-forward switching over cut-through switching?

It determines if a frame has errors before propagating the frame Signup and view all the answers

What happens when an error is detected in a frame?

The switch discards the frame. Signup and view all the answers

What is the primary purpose of store-and-forward switching?

To analyze quality of service (QoS) on converged networks Signup and view all the answers

What is the key difference between fast-forward switching and other cut-through switching methods?

It has lower latency due to immediate forwarding Signup and view all the answers

What happens to faulty packets in fast-forward switching?

They are relayed to the destination NIC, which discards them Signup and view all the answers

Why is store-and-forward switching required for converged networks?

To analyze quality of service (QoS) for traffic prioritization Signup and view all the answers

How does a switch determine the port to forward data in cut-through switching?

By buffering just enough of the frame to read the destination MAC address Signup and view all the answers

What is the primary advantage of cut-through switching over store-and-forward switching?

Lower latency due to immediate forwarding Signup and view all the answers

What is the typical cut-through switching method of switching?

Fast-forward switching Signup and view all the answers

Ethernet Frames and MAC Sublayer

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Questions and Answers

What is the primary function of the MAC sublayer?

What is the purpose of the frame check sequence (FCS) trailer in an Ethernet frame?

What type of access method is used in half-duplex Ethernet?

What is the benefit of using switches in modern Ethernet LANs?

What is the purpose of the back-off algorithm in CSMA/CD?

What type of medium is used in legacy Ethernet?

What is the purpose of the source and destination MAC addresses in an Ethernet frame?

What is the type of topology used in legacy Ethernet?

What type of device will have an Ethernet NIC and a MAC address?

What is the purpose of a unicast MAC address in Ethernet?

What is the process used to determine the destination MAC address associated with an IPv4 address?

What is the destination MAC address of an Ethernet broadcast frame?

How does an Ethernet switch handle an Ethernet broadcast frame?

What happens to an Ethernet broadcast frame when it reaches a router?

What is the significance of the destination IPv4 address in an Ethernet broadcast frame?

What is the purpose of the source MAC address in an Ethernet frame?

What does a switch use to make forwarding decisions?

What happens when a switch is turned on?

What does a switch do when it receives a frame with a new source MAC address?

What happens to an entry in the MAC address table after 5 minutes?

What happens when a switch receives a frame with a source MAC address that exists in the table but on a different port?

What does a switch do when it receives a frame with a unicast destination MAC address?

What is the MAC address table also referred to as?

What is the purpose of the switch examining the source MAC address of the frame?

What happens when a switch receives a frame with a destination MAC address that is not in its table?

How does a switch populate its MAC address table?

What is the advantage of store-and-forward switching?

How many forwarding methods are used by Cisco switches?

What happens when a switch receives a broadcast or multicast frame?

What is the minimum requirement for the cut-through switching method?

What happens when a switch's MAC address table contains the destination MAC address?

What is the purpose of computing the CRC in store-and-forward switching?

What should be the configuration of autonegotiation on both sides of a link?

What is the best practice for configuring Ethernet switch ports?

What type of connection requires a cross-over cable?

What is the purpose of the auto-MDIX feature?

What should you always use when connecting devices?

What is the default state of the auto-MDIX feature on switches running Cisco IOS Release 12.2(18)SE or later?

How can you re-enable the auto-MDIX feature?

What is the reason for not relying on the auto-MDIX feature?

What is the length of an Ethernet MAC address in bytes?

What is the purpose of the organizationally unique identifier (OUI) in an Ethernet MAC address?

What happens when a NIC receives an Ethernet frame with a destination MAC address that does not match its own?

What type of MAC address is an Ethernet NIC configured to accept?

What is the significance of the source MAC address in an Ethernet frame?

What is the purpose of the MAC address in an Ethernet LAN?

How many hexadecimal digits are used to express an Ethernet MAC address?

Why must all Ethernet devices have unique MAC addresses?

What is the primary function of the LLC sublayer in Ethernet?

What is the advantage of using Ethernet technology in LANs?

What is the purpose of the MAC sublayer in Ethernet?

What is the main difference between Ethernet and WLANs?

What is the purpose of the Ethernet frame?

Which standard defines the Layer 2 protocols and Layer 1 technologies used in Ethernet?

What is the primary function of the data link layer in Ethernet?

What is the advantage of using multiple Layer 3 protocols on the same network interface and media?

What does a switch do with the source MAC address of a frame when it is not in the MAC address table?

What happens to an entry in the MAC address table if the source MAC address exists in the table but on a different port?

How does a switch make forwarding decisions?

What is the primary function of a switch in a network?

What is the default time for which an entry stays in the MAC address table?

What is the purpose of a switch examining the source MAC address of every frame?

What does a switch do when it receives a frame with a unicast destination MAC address?

What happens when a switch receives a frame with a destination MAC address that is not in its table?

What is the MAC address table also referred to as?

How does a switch learn new MAC addresses?

What is the advantage of using cut-through switching over store-and-forward switching?

What is the purpose of an unknown unicast in a switch?

What happens when a switch receives a frame with a destination MAC address that is not in its table?

What is the difference between store-and-forward switching and cut-through switching?

What happens when a switch receives a frame with a broadcast or multicast destination MAC address?

What is the benefit of using store-and-forward switching over cut-through switching?

What happens when an error is detected in a frame?

What is the primary purpose of store-and-forward switching?

What is the key difference between fast-forward switching and other cut-through switching methods?

What happens to faulty packets in fast-forward switching?

Why is store-and-forward switching required for converged networks?