Ethernet LAN: MAC Addresses

What happens when a packet with a multicast MAC address is sent to a local network?

The packet is only received by a specific device on the network.
The packet is forwarded by a router to other networks.
The packet is received and processed by a group of devices that belong to the same multicast group. (correct)
The packet is only sent to the device with the corresponding unicast MAC address.

What is the destination MAC address for an IPv4 multicast packet?

01-00-5E (correct)
33-33
AA-AA-AA
FF-FF-FF

What is the purpose of multicast snooping?

To forward multicast packets to other networks.
To prevent multicast packets from being flooded out all Ethernet switch ports. (correct)
To convert a unicast address to a multicast address.
To configure a router to route multicast packets.

What is the role of a Layer 2 Ethernet switch in a network?

To make forwarding decisions based on Layer 2 MAC addresses. (C) Signup and view all the answers

What happens when a multicast packet is sent to a router?

The router only forwards the packet if it is configured to route multicast packets. (A) Signup and view all the answers

What is the purpose of a multicast MAC address?

To identify a group of devices on a network. (A) Signup and view all the answers

What is the source address of a multicast packet?

A unicast address. (D) Signup and view all the answers

What is the role of the MAC address table in a switch?

To make forwarding decisions based on Layer 2 MAC addresses. (A) Signup and view all the answers

What is the primary function of MAC addressing in an Ethernet LAN?

To identify devices at the data link layer of the OSI model (B) Signup and view all the answers

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

6 bytes (D) Signup and view all the answers

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

To ensure that each vendor's MAC addresses are unique (C) Signup and view all the answers

What happens when a NIC receives an Ethernet frame with a non-matching destination MAC address?

It discards the frame (C) Signup and view all the answers

What is the structure of an Ethernet MAC address?

A 6 hexadecimal OUI code followed by a 6 hexadecimal device ID (B) Signup and view all the answers

What type of addresses will an Ethernet NIC also accept frames for?

Broadcast or multicast group addresses (C) Signup and view all the answers

What is the role of the IEEE in ensuring unique MAC addresses?

Vendors register with the IEEE to obtain a unique OUI code (D) Signup and view all the answers

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

To identify the device sending the frame (A) Signup and view all the answers

What happens if the destination MAC address is not in the switch's table?

The switch floods the frame out all ports except the incoming port. (A) Signup and view all the answers

What is the purpose of the MAC address table in a switch?

To determine the outgoing interface for a frame. (B) Signup and view all the answers

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

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

What type of frames are always flooded out all ports except the incoming port?

Broadcast and multicast frames. (D) Signup and view all the answers

How does a switch populate its MAC address table?

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

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

Cut-through switching forwards frames before they are entirely received, while store-and-forward switching waits for the entire frame. (D) Signup and view all the answers

What happens to a frame with a valid CRC in store-and-forward switching?

The frame is forwarded out of the correct port. (C) Signup and view all the answers

What is the primary function of a switch's forwarding method?

To switch frames between network ports. (A) Signup and view all the answers

What happens to a frame when an error is detected?

The switch discards the frame (C) Signup and view all the answers

What type of switching is required for quality of service (QoS) analysis on converged networks?

Store-and-forward switching (B) Signup and view all the answers

Why is it necessary to prioritize VoIP data streams over web-browsing traffic?

To ensure voice over IP data streams have low latency (A) Signup and view all the answers

In cut-through switching, what does the switch buffer?

Just enough of the frame to read the destination MAC address (A) Signup and view all the answers

What is the primary benefit of fast-forward switching?

Lowest level of latency (B) Signup and view all the answers

What happens to packets relayed with errors in fast-forward switching?

The destination NIC discards them (A) Signup and view all the answers

What is the typical cut-through method of switching?

Fast-forward switching (D) Signup and view all the answers

Why might packets be relayed with errors in fast-forward switching?

Because the switch does not perform error checking (D) Signup and view all the answers

What is the primary benefit of fragment-free switching?

It ensures the integrity of the first 64 bytes of a frame (C) Signup and view all the answers

What is the typical size of the frame segment checked for errors in fragment-free switching?

64 bytes (B) Signup and view all the answers

Why is fragment-free switching more reliable than fast-forward switching?

It checks for errors in the first 64 bytes of a frame (B) Signup and view all the answers

What is the purpose of memory buffering on switches?

To store frames before forwarding or when the destination port is busy (B) Signup and view all the answers

In port-based queueing, what happens when a frame is transmitted to the outgoing port?

The frame is transmitted only when all frames ahead in the queue have been successfully transmitted (D) Signup and view all the answers

What is the consequence of a single frame delaying transmission in a port-based queue?

All frames in memory are delayed (D) Signup and view all the answers

What is the characteristic of shared memory buffering on switches?

Frames are stored in a common memory buffer shared by all switch ports (D) Signup and view all the answers

What is the advantage of shared memory buffering on switches?

It enables frames to be received on one port and transmitted on another port (D) Signup and view all the answers