Questions and Answers
What is the primary function of a layer 2 Ethernet switch?
What is the length of a MAC address in bits?
What command can be used to display the physical address of a network interface card on a Windows device?
What is the purpose of an access point in a network?
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What is the representation of a MAC address?
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What is the layer 2 address also known as?
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What is the primary difference between a layer 2 switch and a router?
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What is the function of Switch 1 and Switch 2 in the network topology?
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What is the primary function of a layer 2 switch in a network?
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What is the benefit of having separate collision domains in a network?
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What is the purpose of ARP in a network?
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What is the advantage of full duplex communication in a network?
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What is the default behavior of a layer 2 switch in terms of broadcast domains?
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What is the purpose of a broadcast in a network?
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What is the function of the backplane in a switch?
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What is the benefit of using a layer 2 switch over a hub in a network?
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What is the primary purpose of a layer 2 switch in a network topology?
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What is the purpose of VLANs in a network?
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What is the term for the address assigned by the manufacturer of a network interface card?
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What information does a layer 2 switch use to make forwarding decisions?
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What is the advantage of using unshielded twisted pair (UTP) cables in a network?
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What is the purpose of a switch building a table of layer 2 addresses and corresponding ports?
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What is the term for the address that identifies a network interface card at layer 2?
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What is the benefit of using a layer 2 switch instead of a hub?
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What is the term for the process of a device sending a frame of data into the network, including the source and destination layer 2 addresses?
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What is the purpose of a PC performing an ARP request?
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What is the role of the switch in forwarding a frame of data from a PC to the default gateway?
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What is the term for the address that a network interface card uses to identify itself at layer 2?
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What is a characteristic of a switch that makes it better than a hub?
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What is the number of collision domains on a 48-port switch?
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What is the number of broadcast domains on a 48-port switch by default?
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What is the purpose of a switch learning layer 2 addresses?
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What command can be used to show the layer 2 addresses learned by a switch?
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What is the significance of a switch having full duplex capabilities?
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What is the purpose of a switch storing layer 2 addresses in a table?
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What happens when a device sends a broadcast on a layer 2 switch?
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What is the significance of a switch having 48 ports?
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What is the purpose of a switch dynamically learning layer 2 addresses?
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What is the reason why the switch has not learned the MAC address of PC3 initially?
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When PC1 sends a unicast frame to its default gateway, which of the following is true?
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What is the command used by PC3 to display the details of its ethernet adapter?
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What is the purpose of the ARP request sent by PC3?
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What happens when PC1 sends a broadcast frame into the network?
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Why did the ping to 172.20.5.1 not result in a broadcast?
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What is the result of the switch learning the MAC address of PC3?
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What is the purpose of an ARP request?
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What is the significance of each port on the switch being its own collision domain?
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Why did the ping to 172.20.5.99 result in three broadcasts?
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What is a significant characteristic of a layer 2 switch in terms of broadcast domains?
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What happens when the switch receives a frame destined for a MAC address it has learned?
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What is the primary advantage of a layer 2 switch over a layer 2 bridge?
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Why does the switch not need to send frames to every port when it receives a frame destined for a known MAC address?
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What is the result of a switch receiving a frame with an unknown destination MAC address?
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What is an important distinction between layer 2 switching and layer 3 forwarding?
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What is the purpose of a layer 2 switch in a network?
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What is the result of capturing traffic on eth0 while sending traffic from PC3?
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What is the result of a device sending a frame with a broadcast destination MAC address?
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What is the role of a layer 2 switch in a network with multiple routers?
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Why does the switch learn the MAC address of PC3 when it sends traffic?
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What is a key advantage of using multiple collision domains in a network?
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Why did the ping to 172.20.5.50 result in a successful response?
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What is true about the devices connected to the switch?
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What happens when a device sends a unicast frame to a MAC address that is not in the switch's MAC address table?
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What is the primary difference between a layer 2 switch and a layer 2 bridge?
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What is the effect of a broadcast sent from a device connected to a layer 2 switch?
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What is the relationship between layer 2 switching and the forwarding of data between routers?
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What is a layer 2 bridge commonly used for?
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What is the primary benefit of full-duplex communication on a layer 2 switch?
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Study Notes
Layer 2 Switches
- A Layer 2 switch makes forwarding decisions based on Layer 2 addresses, specifically Media Access Control (MAC) addresses.
- A MAC address is 48 bits long, represented by 12 hexadecimal characters, each representing 4 bits.
- Each network interface card (NIC) has a unique MAC address.
Learning MAC Addresses
- A Layer 2 switch builds a table of MAC addresses associated with each port.
- The switch learns MAC addresses by looking at the source MAC address of incoming frames.
- When a device sends a frame, the switch updates its table with the MAC address and the port it is connected to.
Forwarding Decisions
- When a switch receives a frame, it checks the destination MAC address and forwards it to the port associated with that MAC address.
- If the switch doesn't know the MAC address, it forwards the frame to all ports (flooding).
- A switch can operate in full duplex, allowing devices to send and receive frames simultaneously.
Collision Domains and Broadcast Domains
- Each port on a switch is its own collision domain, reducing collisions and increasing network efficiency.
- A switch has one broadcast domain, meaning a broadcast frame is sent to all ports.
ARP Requests
- An ARP (Address Resolution Protocol) request is a broadcast frame sent to resolve an IP address to a MAC address.
- The switch forwards ARP requests to all ports in the broadcast domain.
- The device responding to the ARP request sends a unicast frame with its MAC address, which the switch learns and updates its table.
Switch Configuration and Demonstration
- A show mac address-table command can be used to display the switch's MAC address table.
- The switch can be configured to capture packets and display the MAC address table to demonstrate learning and forwarding decisions.
- A Layer 2 switch with 48 ports would have 48 collision domains and one broadcast domain.### Ping and ARP Request
- When a ping is sent, it sends an ARP request as a broadcast to find the layer 2 address of the device with the specified IP address
- The ARP request is sent to all devices on the same broadcast domain, including PC2 and PC3
- If the IP address is not found, the ping will fail and an ARP request will be sent again
Layer 2 Switching
- A layer 2 switch is a single broadcast domain, where all devices receive broadcast messages
- A layer 2 switch forwards broadcast messages to all active ports
- A layer 2 switch improves upon a layer 2 bridge by giving every device its own collision domain on its own port
- This allows every device connected to a layer 2 switch to send and receive at the same time, making it full duplex on every port
Layer 2 Bridge
- A layer 2 bridge is a stepping stone to layer 2 switching, with only a couple of ports
- A layer 2 bridge divides a single collision domain into multiple collision domains, one for each port
Layer 2 Forwarding
- Layer 2 forwarding occurs between devices, such as between a PC and a switch, and between switches
- Layer 2 switching happens between routers, where switches forward data based on layer 2 addresses
- Layer 2 forwarding is what happens between routers, where switches make forwarding decisions based on layer 2 addresses
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Description
This quiz covers the basics of layer 2 Ethernet switches, their role in network infrastructure, and their functionality. It explores the topology of switches and their connections to servers and computers.