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Questions and Answers
What is the primary function of a layer 2 Ethernet switch?
What is the primary function of a layer 2 Ethernet switch?
What is the length of a MAC address in bits?
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 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?
What is the purpose of an access point in a network?
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What is the representation of a MAC address?
What is the representation of a MAC address?
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What is the layer 2 address also known as?
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?
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?
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?
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?
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?
What is the purpose of ARP in a network?
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What is the advantage of full duplex communication in a network?
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?
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?
What is the purpose of a broadcast in a network?
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What is the function of the backplane in a switch?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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?
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.