Podcast
Questions and Answers
What is the purpose of the Preamble in an Ethernet frame?
What is the purpose of the Preamble in an Ethernet frame?
The Frame Check Sequence (FCS) field in an Ethernet frame is used to determine the MAC address.
The Frame Check Sequence (FCS) field in an Ethernet frame is used to determine the MAC address.
False
What is the size in bytes of a MAC address?
What is the size in bytes of a MAC address?
6
The Frame Check Sequence (FCS) uses a _____ algorithm to detect corrupted data.
The Frame Check Sequence (FCS) uses a _____ algorithm to detect corrupted data.
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If the Type field in an Ethernet frame has a value of 0x0800, what does it indicate?
If the Type field in an Ethernet frame has a value of 0x0800, what does it indicate?
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What is the purpose of the Address Resolution Protocol (ARP)?
What is the purpose of the Address Resolution Protocol (ARP)?
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Match the Ethernet frame components with their functions:
Match the Ethernet frame components with their functions:
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ARP Requests are sent as unicast messages.
ARP Requests are sent as unicast messages.
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The Start Frame Delimiter (SFD) consists of 7 bytes.
The Start Frame Delimiter (SFD) consists of 7 bytes.
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What does the command 'arp -a' do?
What does the command 'arp -a' do?
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What does the value of 1536 or greater in the Type field signify?
What does the value of 1536 or greater in the Type field signify?
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The type of ARP entry learned via ARP is called ______.
The type of ARP entry learned via ARP is called ______.
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Match the following messages with their descriptions:
Match the following messages with their descriptions:
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Which message is used for testing network reachability?
Which message is used for testing network reachability?
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Switch interfaces are administratively down by default.
Switch interfaces are administratively down by default.
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What state do router interfaces default to when configured?
What state do router interfaces default to when configured?
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What is the size of a MAC address in bits?
What is the size of a MAC address in bits?
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A MAC address is also known as a Burned-In Address (BIA).
A MAC address is also known as a Burned-In Address (BIA).
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What does the first 3 bytes of a MAC address represent?
What does the first 3 bytes of a MAC address represent?
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Dynamically learned MAC addresses are removed from the MAC address table after ___ minutes of inactivity.
Dynamically learned MAC addresses are removed from the MAC address table after ___ minutes of inactivity.
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What is the minimum size for an Ethernet frame including header and trailer?
What is the minimum size for an Ethernet frame including header and trailer?
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Match the format of MAC address to the appropriate device type:
Match the format of MAC address to the appropriate device type:
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A unicast frame is a frame that is destined for multiple targets.
A unicast frame is a frame that is destined for multiple targets.
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What is added to the Ethernet frame payload if it is less than 46 bytes?
What is added to the Ethernet frame payload if it is less than 46 bytes?
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What type of duplex do devices connected to a hub operate in?
What type of duplex do devices connected to a hub operate in?
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Devices connected to a switch can operate in half duplex.
Devices connected to a switch can operate in half duplex.
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Describe the role of CSMA/CD in networking.
Describe the role of CSMA/CD in networking.
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When autonegotiation is disabled, the switch uses the ______ supported speed.
When autonegotiation is disabled, the switch uses the ______ supported speed.
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What happens if a collision occurs while using CSMA/CD?
What happens if a collision occurs while using CSMA/CD?
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Jamming signals are sent only when a device detects it is safe to transmit.
Jamming signals are sent only when a device detects it is safe to transmit.
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What are input errors in networking?
What are input errors in networking?
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Study Notes
Ethernet LAN Overview
- Local Area Networks (LANs) utilize Ethernet technology for data transmission within a limited geographical area.
Ethernet Frame Structure
- Comprises a header, trailer, and payload (packet); typically spans 26 bytes.
- Header includes:
- Preamble: 7 bytes for synchronization (alternating 1's and 0's).
- Start Frame Delimiter (SFD): 1 byte (10101011) marks frame start.
- Destination MAC Address: 6 bytes identifying the receiver.
- Source MAC Address: 6 bytes identifying the sender.
- Type/Length: 2 bytes indicating either length of the payload or type of encapsulated packet.
- Trailer includes Frame Check Sequence (FCS): 4 bytes for error detection using CRC (Cyclic Redundancy Check).
Preamble and SFD
- Preamble assists in synchronizing device clocks before a frame is received.
- SFD signals the end of the preamble and the beginning of the frame data.
MAC Address Details
- MAC addresses consist of 6 bytes (48 bits); globally unique to each device.
- First 3 bytes represent the Organizationally Unique Identifier (OUI) assigned to the manufacturer.
- Display formats vary (e.g., Windows: 5C-23-5A-24-2B-3D, Cisco: 0011.5ccc.5c00).
Frame Check Sequence (FCS)
- A 4-byte field used to detect errors in frame data.
- Implements CRC algorithm to ensure data integrity.
ARP (Address Resolution Protocol)
- Used to map Layer 3 IP addresses to Layer 2 MAC addresses.
- Functions with two primary messages:
- ARP Request: Broadcast to all devices seeking the MAC address for a known IP.
- ARP Reply: Unicast message providing the requested MAC address.
Ping Utility
- Tests network reachability using ICMP Echo Request and ICMP Echo Reply messages.
Switch Interfaces and MAC Address Tables
- Switch interfaces default to "up" status when correctly connected.
- MAC Address tables maintain dynamic entries, learning MAC addresses of connected devices.
- Dynamic MAC addresses are removed after 5 minutes of inactivity.
Full/Half Duplex Communication
- Half Duplex: Allows sending or receiving but not simultaneously; typical for hub connections.
- Full Duplex: Allows simultaneous sending and receiving; utilized in switch connections.
Collision Management with CSMA/CD
- Carrier Sense Multiple Access with Collision Detection helps manage network traffic.
- Devices listen before transmitting, sending a jamming signal if a collision occurs, followed by random wait times before reattempting.
Speed and Duplex Autonegotiation
- Devices automatically negotiate optimal speed and duplex settings.
- Common speeds include 10, 100, and 1000 megabits per second.
Common Networking Errors
- Runts: Frames smaller than 64 bytes.
- Giants: Frames larger than 1518 bytes.
- CRC Errors: Frames failing the CRC check.
- Input/Output errors: Total counts of various error types occurring in the network.
Command Line Interface (CLI) Commands
- Commands such as
show ip int br
provide interface status and troubleshoot configurations. - Use
arp -a
in command prompt to view the ARP table on various platforms.
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Description
Test your knowledge on Ethernet LAN switching based on Module 5. The quiz covers key components of Local Area Networks, including Ethernet frames, headers, and packets. Prepare to challenge your understanding of network communications.