Ethernet Questions and Answers
Discover valuable insights into Ethernet with our comprehensive collection of questions and answers to enhance your knowledge. This resource provides a wealth of knowledge on Ethernet technology, protocols, configurations, troubleshooting, and more. Explore a wide range of topics to enhance your understanding and stay up to date with the latest advancements in networking.
What is Ethernet?
Ethernet is a widely deployed LAN technology. It was developed by Xerox from an earlier specification called Alohanet. Ethernet uses a physical layer and data link layer for transmission and has been updated to offer higher capacities and speeds.
Can you mention some of the Ethernet standards?
Some of the Ethernet standards include:
- 10BASE-T: 10 Mbps, twisted pair cable
- 100BASE-TX: 100 Mbps, two pairs of high-quality twisted-pair cables
- 1000BASE-T: 1 Gbps, four pairs of Cat 5 UTP
- 10GBASE-T: 10 Gbps, copper twisted pair cable
- 40GBASE-T: 40 Gbps, copper twisted pair cable
What is CSMA/CD in Ethernet?
CSMA/CD (Carrier Sense Multiple Access / Collision Detection) is the protocol for carrier transmission in Ethernet networks. On Ethernet, any device can try to send a frame at any point in time. They listen to the wire (carrier sense) and if no one else is transmitting they start their transmission. If two devices transmit at once, a collision occurs and is detected by all listening devices. After a random time interval, the devices that collided try to transmit again.
Explain the difference between half-duplex and full-duplex Ethernet?
Half-duplex Ethernet is when data transmission can occur in two directions on the same signal carrier but not at the same time. Full-duplex Ethernet allows for simultaneous transmission of data in both directions on the signal carrier.
What is the purpose of a MAC address?
A MAC (Media Access Control) address is a hardware identification number that uniquely identifies each device on a network. The MAC address is used to determine where packets will be sent on a network.
Why do we use switches in Ethernet networks?
Switches are used to connect multiple devices on an Ethernet network. They channel incoming data from any of the multiple input ports to the specific output port that will take the data toward its intended destination. This allows for simultaneous communication across the network, improving efficiency.
What does a frame check sequence (FCS) in an Ethernet frame do?
FCS is a type of checksum algorithm used to detect errors in data transmission. It ensures that the data received at the destination are exactly the same as they were at the source.
What is the difference between a crossover cable and a straight-through cable?
A crossover cable is used to connect two similar devices directly, like PC to PC or switch to switch. In contrast, a straight-through cable is used to connect two different types of devices, like a PC to a switch or a PC to a router.
How does Gigabit Ethernet differ from its predecessors?
Gigabit Ethernet provides a much higher bandwidth than its predecessors, achieving data rates up to 1,000 Mbps, or 1 Gbps. This is 10 times faster than Fast Ethernet (100 Mbps) and 100 times faster than traditional Ethernet (10 Mbps).
What is the role of the Ethernet header?
The Ethernet header contains the MAC address of the source and the destination, as well as the EtherType field, which indicates the protocol type of the payload data.
Explain the concept of VLAN?
VLAN (Virtual Local Area Network) is a logical grouping of network users and resources connected to administratively defined ports on a switch. It allows for greater flexibility as VLANs can be set up without major physical changes in the network infrastructure.
What is the maximum length for an Ethernet cable?
For Ethernet networks (10BASE-T and 100BASE-TX), the maximum length for an Ethernet cable is 100 meters. This includes a maximum length of 90 meters of solid “horizontal” cabling between the patch panel and the wall jack, plus 5 meters of stranded patch cable between each jack and the attached device.
What is the purpose of an Ethernet switch?
An Ethernet switch is used to create a network. It serves as a central node that forwards data frames to the intended client.
How does Ethernet differ from Wi-Fi?
Ethernet is a standard for wired data networks, while Wi-Fi is a standard for wireless networks. Ethernet typically provides faster speed and better reliability but has less mobility compared to Wi-Fi.
What is the primary advantage of using Ethernet?
The primary advantage of Ethernet is that it provides a reliable, high-speed connection with low latency. It is also easy to set up and relatively inexpensive.
What is the difference between an Ethernet hub and an Ethernet switch?
A hub broadcasts incoming data packets to all devices on the network, while a switch intelligently forwards the data packets to the intended device.
What are the limitations of Ethernet technology?
The limitations of Ethernet technology include a maximum cable length, data transmission speed limitations depending on the cable type and quality, and the potential for data collisions in non-switched networks.
Explain what Ethernet bonding is?
Ethernet bonding, also known as NIC teaming, is a technique that allows you to combine multiple Ethernet network interfaces into a single virtual interface. This can provide higher bandwidth, load balancing, or fault tolerance.
What are the different types of Ethernet cables?
There are several types of Ethernet cables, including Cat 5, Cat 5e, Cat 6, Cat 6a, Cat 7, Cat 7a, and Cat 8, each offering different levels of performance and bandwidth.
What is Jumbo Frame in Ethernet communication?
A Jumbo Frame is an Ethernet frame that carries more than the standard payload of 1500 bytes. Jumbo Frames can carry up to 9000 bytes of payload, which can help to improve the efficiency of data transmission over high-speed networks.
What is the function of the Physical layer in Ethernet?
The Physical layer in Ethernet is responsible for the transmission and reception of raw bit streams over a physical medium. It defines the electrical/optical, mechanical, and functional interfaces to the transmission medium.
What do you know about the Ethernet II frame format?
The Ethernet II frame format, also known as DIX (DEC-Intel-Xerox) Ethernet, is the most commonly used Ethernet frame format. It includes destination and source MAC addresses, an EtherType field to identify the upper layer protocol, a payload field, and a Frame Check Sequence for error detection.
How does Ethernet use MAC addresses?
Ethernet uses MAC addresses to uniquely identify devices on a network. The MAC address is hard-coded into a network interface controller (NIC) and is used to direct data to the correct destination.
What is ARP and what is its role in Ethernet?
The Address Resolution Protocol (ARP) is a protocol used to map an IP address to a MAC address on a local network. It plays a crucial role in Ethernet networking as it allows for the communication of IP packets between hosts on the same network segment.
What is a collision domain?
A collision domain is a network segment where one particular device’s transmission can collide with another’s. In a hub-based Ethernet network, the entire network is a single collision domain. Switches and bridges can break a network into multiple collision domains.
Can you explain the difference between Unicast, Broadcast, and Multicast frames?
Unicast frames are intended for one specific device. Broadcast frames are intended for all devices in the broadcast domain. Multicast frames are intended for a group of devices that “subscribe” to a multicast address.
What is the use of a gateway in a network?
A gateway is a network point that acts as an entrance to another network, often connecting networks that use different protocols. It allows devices on different networks to communicate with each other.
What is a Broadcast Storm?
A broadcast storm occurs when there are so many broadcast messages on a network segment that they consume most of the available bandwidth, thus degrading network performance.
What is Ethernet Auto-negotiation?
Auto-negotiation is an Ethernet procedure by which two connected devices choose common transmission parameters, such as speed, duplex mode, and flow control. This ensures the best possible shared settings for communication.
Explain the difference between Baseband and Broadband?
Baseband transmission sends a digital or analog signal over a dedicated line with a single channel. Broadband transmission sends multiple signals of multiple frequencies over a single cable, dividing the total capacity of the cable into separate distinct channels for different purposes.
What is Wake-on-LAN (WoL) and how does it work?
Wake-on-LAN (WoL) is an Ethernet networking standard that allows a computer to be turned on or awakened by a network message. The message is usually sent by a software program executed on another device connected to the same local area network.
How can you secure an Ethernet network?
An Ethernet network can be secured using various methods including encryption, MAC address filtering, VLAN segregation, and implementing firewalls.
Explain the purpose of a traceroute command?
The traceroute command is used to track the journey that a packet takes from the source computer to the destination computer. It shows each of the network hops and the time it took for each hop.
What is the role of the Data Link Layer in Ethernet?
The Data Link Layer is responsible for the transfer of data between network entities and the detection and possible correction of errors that may occur in the Physical Layer.
What is an Ethernet frame?
An Ethernet frame is a data packet that is sent over the network. The Ethernet frame structure contains several fields including destination and source MAC addresses, EtherType field, payload (data), and CRC.
What are Managed and Unmanaged switches?
Managed switches provide more control over your LAN traffic and offer advanced features to control that traffic. An unmanaged switch simply allows Ethernet devices to communicate with one another.
What is the Preamble in an Ethernet frame?
The Preamble in an Ethernet frame is a 7-byte sequence used to alert receivers on the Ethernet link that a frame is coming, and to synchronize the frame reception.
Explain MTU in networking?
The Maximum Transmission Unit (MTU) is the largest size packet or frame, specified in bytes, that can be sent over a network interface. Ethernet’s default MTU is 1500 bytes.
What is the EtherType field in an Ethernet frame?
The EtherType field in an Ethernet frame is used to indicate the protocol of the payload data, such as IPv4 or IPv6.
What is the Interframe gap in Ethernet?
The Interframe gap is a period of silence (96-bit times) on the Ethernet medium between each frame. It gives the receiving device time to process the previous frame and get ready for the next one.
How does a switch learn MAC addresses?
A switch learns MAC addresses by examining the source MAC address of each frame it receives and adding these addresses to a Forwarding Information Base (FIB) also known as a MAC address table.
What is Fast Ethernet?
Fast Ethernet is an extension of Ethernet that provides speeds of up to 100 Mbps. It uses the same CSMA/CD protocol and can use existing twisted-pair copper wire or fiber-optic cabling.
What is an Ethernet splitter?
An Ethernet splitter takes advantage of the fact that 10MBit and 100MBit Ethernet only use 4 out of 8 wires. It allows two Ethernet cables to share one single long-distance cable, with the help of an Ethernet switch at each end.
What is a Media Converter in Ethernet Networks?
A Media Converter is a device that converts data signals from one media type to another. In Ethernet networks, they are typically used to convert between copper-based Ethernet and fiber-optic-based Ethernet.
How does Priority Flow Control (PFC) work in Ethernet?
Priority Flow Control (PFC) is a mechanism in Ethernet that prevents frame loss due to congestion. It uses the concept of “pause frames” to temporarily halt the transmission of data frames on a particular priority level when congestion is detected.
What is the importance of Duplex settings in Ethernet?
Duplex settings are important in Ethernet to determine how data transmission occurs over a link. Half-duplex allows for data transmission in both directions, but not at the same time, while full-duplex allows for simultaneous data transmission in both directions.
What is the purpose of a Cyclic Redundancy Check (CRC) in Ethernet?
The Cyclic Redundancy Check (CRC) in Ethernet is used for error checking in the transmitted frames. If any discrepancies are found between the data received and the CRC, it suggests that an error has occurred during transmission.
What is link aggregation in Ethernet?
Link aggregation, also known as port trunking, is the combination of multiple physical Ethernet links to form a logical Ethernet link to increase bandwidth and provide redundancy in case one of the links should fail.
What is an Ethernet controller?
An Ethernet controller is a piece of computer hardware that manages an Ethernet connection. It handles communication over a network whether that be data transfer or hardware interface needs.
What is the difference between a network hub and a network switch?
A network hub broadcasts incoming data to all ports, whereas a network switch forwards data only to the port that leads to the destination device.
What is the basic unit of data transfer in Ethernet?
The basic unit of data transfer in Ethernet is the frame.
What is a collision in Ethernet terms?
A collision in Ethernet terms refers to a situation where two or more devices attempt to send a packet simultaneously on a shared network segment, causing an overlap of the packets.
What does TCP/IP stand for?
TCP/IP stands for Transmission Control Protocol/Internet Protocol, which is a set of rules governing communications among all devices on the Internet.
What is an Ethernet port?
An Ethernet port is a physical socket on a computer, router, or networking device where an Ethernet cable can be connected.
What is an Ethernet driver?
An Ethernet driver is a program that allows the operating system to interact with the Ethernet hardware.
What is a MAC flood?
MAC flooding is a type of network attack where the attacker floods the switch with a large number of frames, each with different source MAC addresses. This overwhelms the switch’s MAC table and forces it to broadcast incoming packets to all ports.
What is the advantage of using fiber optic cables in Ethernet?
Fiber optic cables offer high bandwidth, low signal loss, and are immune to electromagnetic interference. They also allow for longer distances between network nodes compared to copper cabling.
What is a packet in Ethernet terms?
A packet is a formatted unit of data carried by a packet-switched network. In Ethernet, a packet is contained within a frame.
What does a Network Interface Card (NIC) do?
A Network Interface Card (NIC) is a hardware component that connects a computer to a network. It is responsible for converting data into a format that can be transmitted over the network.
What is the maximum data rate of Gigabit Ethernet?
The maximum data rate of Gigabit Ethernet is 1 gigabit per second (Gbps), or 1000 megabits per second (Mbps).
What is a switch fabric?
A switch fabric is the internal pathway of a switch through which data is transferred from one port to another.
What does ‘Base’ mean in ’10Base-T’?
‘Base’ in ’10Base-T’ stands for baseband. This means that the Ethernet signal is the only signal carried on the medium.
How does Ethernet handle frame collisions?
Ethernet uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection) protocols to handle frame collisions. When a collision is detected, each device waits a random amount of time and then attempts to retransmit the frame.
What is a router and how is it different from a switch?
A router is a networking device that connects multiple networks and routes network traffic between them. A switch, on the other hand, connects devices within the same network.
What is the role of a Network Protocol?
A network protocol defines rules and conventions for communication between network devices. It covers authentication, error detection and correction, and data synchronization.
What is Quality of Service (QoS) in Ethernet?
Quality of Service (QoS) in Ethernet is a set of techniques to manage network resources and provide different priority to certain types of data, applications, or users to guarantee a certain level of performance.
What is Power over Ethernet (PoE)?
Power over Ethernet (PoE) is a technology that allows network cables to carry electrical power, reducing the number of cables that must be run and simplifying installations.
What is Ethernet over powerline?
Ethernet over powerline (EoP) technology uses the existing electrical wiring in a building to transmit network data. It is often used in situations where Wi-Fi signal is weak or where running Ethernet cabling is difficult or expensive.
What is a broadcast domain?
A broadcast domain is a logical division of a computer network, in which all nodes can reach each other by broadcast at the data link layer.
What is a cross-over cable?
A cross-over cable is a type of Ethernet cable that is used to connect two devices directly, such as two computers or two switches.
What is the difference between a static IP address and a dynamic IP address?
A static IP address is fixed and does not change, whereas a dynamic IP address is assigned by a DHCP server and can change over time.
What is a default gateway?
A default gateway is a router or network device that a networked device uses to send information to a device in another network or the internet.
What is Ethernet/IP?
Ethernet/IP (Industrial Protocol) is an industrial network protocol that adapts the Common Industrial Protocol to standard Ethernet.
What is TCP Offload Engine (TOE)?
TCP Offload Engine (TOE) is a technology used in network interface cards (NIC) to offload processing of the TCP/IP stack to the network controller. It is used to reduce the CPU overhead of TCP/IP processing.
What is Spanning Tree Protocol (STP)?
Spanning Tree Protocol (STP) is a network protocol that prevents loop by creating a spanning tree within a mesh network of connected layer-2 bridges (typically Ethernet switches), and disables those links that are not part of the tree, leaving a single active path between any two network nodes.
What is the function of an Ethernet repeater?
An Ethernet repeater is a network device used to extend the reach of an Ethernet network by regenerating the Ethernet signal.
What is cut-through switching?
Cut-through switching is a method of packet forwarding where the switch starts forwarding a packet before it has received the whole packet.
What is the function of an Ethernet terminator?
An Ethernet terminator is used in coaxial Ethernet networking to indicate the end of the network.
What is a ping?
Ping is a utility used to test the reachability of a host on a network and to measure the round-trip time for packets sent from the local host to a destination computer.
What is a subnet mask?
A subnet mask is used to divide an IP address into two parts. One part identifies the host (computer), the other part identifies the network to which it belongs.
What is a Domain Name System (DNS)?
The Domain Name System (DNS) translates internet domain and host names to IP addresses and vice versa.
What is an IP address?
An IP address is a unique string of numbers separated by periods that identifies each computer using the Internet Protocol to communicate over a network.
What is an Ethernet loop and how can it be prevented?
An Ethernet loop occurs when there is more than one active path between two nodes. It can cause a broadcast storm and disrupt network performance. It can be prevented using the Spanning Tree Protocol (STP).
What is the function of a packet switch?
A packet switch is a device that receives, processes, and forwards electronic packets of data to their intended destinations on a network.
What is the advantage of VLAN?
Virtual Local Area Networks (VLAN) help to structure a network by creating separate broadcast domains. This can improve network performance and provide better security.
What is port mirroring?
Port mirroring is used on a network switch to send a copy of network packets seen on one switch port (or an entire VLAN) to a network monitoring connection on another switch port.
What is the difference between TCP and UDP?
TCP (Transmission Control Protocol) is a connection-oriented protocol and offers full duplex communication, which means both parties can communicate with each other simultaneously. UDP (User Datagram Protocol) is a connection-less protocol. Communication is done through message exchange.
What is MAC address aging?
MAC address aging is a process that ages out dynamic entries in the MAC address table after a certain period, allowing for old or unused MAC addresses to be removed.
What is an IP conflict?
An IP conflict occurs when two or more devices or computers on the same network are assigned the same IP address.
What is Port Forwarding?
Port forwarding is a technique that is used to allow external devices access to computer services on private networks.
What is multicasting?
Multicasting is the process of broadcasting data packets to a group of endpoints in a network instead of sending packets to every node.
What is the difference between Half Duplex and Full Duplex communication?
Half Duplex communication allows data transmission in both directions, but not simultaneously. In a full duplex, data transmission and reception occur simultaneously.
What is the purpose of the Ethernet Type field?
The Ethernet Type field in the Ethernet frame is used to indicate which protocol is encapsulated in the payload of the frame.
What is a VLAN Trunking Protocol (VTP)?
VLAN Trunking Protocol (VTP) is a Cisco proprietary protocol that distributes and synchronizes information about VLANs configured across switches on the same network.
What is a default VLAN?
A default VLAN is a VLAN that all switch ports are placed into when the switch is reset to factory defaults. Typically, it’s VLAN 1.
What is an Ethernet tap?
An Ethernet tap is a hardware device that provides a way to access the data flowing across a computer network.
What is RARP and what is it used for?
Reverse Address Resolution Protocol (RARP) is a protocol used to resolve an IP address from a given hardware address (such as an Ethernet address).