ETHERNET LOCAL AREA NETWORKS
Which IEEE 802.1p traffic class represents standard data (best effort) traffic?
0
What is the maximum cable length for 100BaseTx Ethernet?
100 m
What is the maximum length of a 10GBase-T Ethernet connection using category 7 (CAT-7) shielded twisted-pair (STP) cable?
100 m.
Which of the following is a Gigabit Ethernet specification for copper cable?
1000BaseCX
Which of the following is NOT a Gigabit Ethernet fiber cabling specification?
1000BaseFX
Which interfaces are NOT considered parts of the IEEE 802.3ae standard?
10GBaseCX4
Which 10GbE interfaces operate over multimode fiber (MMF) cabling? (Choose two.)
10GBaseLX4 10GBaseSR
supports direct host connections over Category 6 or higher wiring.
10GBaseT
builds high-bandwidth LAN and WAN backbones.
10GbE
According to the Ethernet 5/4/3 rule, how many 10Base2 segments may have nodes attached?
3
What is the maximum length of a 10GbE segment through single-mode fiber (SMF) cable?
40 km
What is Ethernet?
A Data Link Layer specification for media access control (MAC), which defines how network nodes can use a shared medium to transmit signals to one another.
How does a Layer 2 switch differ from a Layer 3 switch?
A Layer 2 switch makes decisions based on media access control (MAC) addresses.
How does a Layer 3 switch differ from a router?
A Layer 3 switch checks the first packet in each stream; a router checks each packet.
improves network performance by dividing the network into separate collision domains but not separate broadcast domains.
A switch
What is the difference between a switch and a hub?
A switch allows a dedicated path between two ports.
Virtual local area networks (VLAN) are typically implemented using which type of device?
A switch.
The network interface card (NIC) in an Ethernet node receives from the Internet protocol (IP) a packet 12 bytes long. What must the NIC do in order to prepare the packet for transmission across the physical network?
Add padding, a header and a trailer.
How is Fast Ethernet similar to standard Ethernet?
All of the above.
Layer 3 switches do a good job of containing which of the following?
Broadcasts.
Where are Ethernet frames processed?
By the network interface card (NIC) at the Data Link Layer
The IEEE 10GBaseT networks operate over which type of cabling?
Category 6 unshielded twisted-pair (UTP).
Devices connected to hubs share the same:
Collision domain.
What layer of software is normally loaded on the network interface card (NIC)?
Data Link Layer
Originally developed in the 1970s by Xerox Corporation in conjunction with Intel and Digital Equipment Corporation (DEC), is now the primary medium for local area networks (LAN). The original commercial Ethernet has 10-Mbps throughput and uses the carrier sense multiple access with collision detection (CSMA/CD) method to access the physical medium. Fast Ethernet (100-Mbps Ethernet), Gigabit Ethernet (1,000-Mbps Ethernet) 10 Gigabit and faster speeds are later technologies based on the original construct.
Ethernet
What is the most widely installed local area network (LAN) technology?
Ethernet
in a star/bus topology, is the most common LAN protocol used today.
Ethernet
Which of the following statements is incorrect regarding Ethernet?
Ethernet can only be used with Category 5E unshielded twisted-pair (UTP) cable.
Which of the following statements are true concerning Ethernet networks? (Choose two.)
Ethernet can use thicknet, thinnet, or twisted pair cable at the Physical Layer. Media access control (MAC) frames are transmitted across the physical media.
Gigabit Ethernet uses a different frame format than 10 Mbps Ethernet and Fast Ethernet. True or False?
False
is identical to 10 Mbps Ethernet, only faster.
Fast Ethernet
A high-speed network technology (commonly running at 1-, 2-, 4-, 8- 16-, 32-, and 128-gigabit speeds) primarily used for storage networking. FC is a standard connection type for storage area networks (SAN) in enterprise storage.
Fiber Channel (FC)
Which Layer 2 switch type reads the first 64-bytes of a frame and then forwards it to the destination interface?
Fragment-free
You are shopping for a new Ethernet switch. You want maximum switch throughput, but also want to avoid passing frames damaged by collisions. Which type of switch should you choose?
Fragment-free
Which Layer 2 switch type reads the first 64 bytes of a frame and then forwards it to the destination interface?
Fragment-free.
preserves the existing Ethernet frame format and only runs in full- duplex mode.
Gigabit Ethernet
Which of the statements below is incorrect when comparing Gigabit Ethernet to Fast Ethernet technology?
Gigabit Ethernet uses the same speed as Fast Ethernet
Which of the following best describes the functionality of a virtual local area network (VLAN)?
Grouping nodes logically that may be physically separated
A vendor-neutral standard for virtual local area network (VLAN) implementation. The standard specifies a 2-byte VLAN tag that includes a 12-bit VLAN identifier, used by the network switches or bridges to decide to which network segment they should forward each frame. The last switch to handle the tagged frame before passing it to the destination node strips the header from the frame.
IEEE 802.1Q
Which IEEE standard describes vendor-neutral virtual local area network (VLAN) tagging on bridged networks?
IEEE 802.1Q
Allows prioritization of media access control (MAC) layer frames on the network. IEEE 802.1p uses 3 bits of the IEEE 802.1Q virtual local area network (VLAN) tag to represent one of eight possible priority values, each mapped to one of eight traffic classes.
IEEE 802.1p
Which Ethernet frame format includes a length field in the media access control (MAC) header?
IEEE 802.3
Ethernet IEEE standards
IEEE 802.3u offered 100 Mbps operation (also called Fast Ethernet) IEEE 802.3x enabled full duplex operation and flow control IEEE 802.3z offered 1,000 Mbps operation (also called Gigabit Ethernet) IEEE 802.3ae offered 10,000 Mbps operation (also called 10 Gigabit Ethernet) IEEE 802.3ah offered "Ethernet in the First Mile" access network Ethernet
Why would you replace a hub with a switch?
Increase local area network (LAN) performance.
A Cisco-specific encapsulation technique that adds a 26-byte header with a 15-bit virtual local area network (VLAN) identifier and a 4-byte cyclic redundancy check (CRC) trailer to an existing frame as it traverses a trunk link. The header includes a VLAN ID, source and destination address (DA) information, length, and other fields. This information is stripped from the frame before it reaches the destination device.
Inter-Switch Link (ISL) frame tagging
A Network Layer protocol responsible for getting a packet (datagram) through a network using Layer 3 Internet protocol (IP) addresses. It is the "IP" in Transmission Control Protocol/Internet Protocol (TCP/IP).
Internet Protocol (IP)
Which capability is NOT provided by Layer 3 switching.
Internet protocol (IP) to name resolution for forwarding.
What does an Ethernet frame addressed with a "1" as the first bit of destination media access control (MAC) address do?
It allows all frames to be multicast to a select group of nodes.
Which statement best describes 10 Gigabit Ethernet (10GbE)?
It can be used in place of Fiber Channel (FC) as a storage attachment technology.
is essentially very high-speed routing.
Layer 3 switching
A Data Link Layer protocol used to control the flow of information across a physical link. LLC is used in Ethernet networks that use the IEEE frame type, which does not include a type field but rather a length field.
Logical Link Control (LLC)
One of the media-specific Institute of Electrical and Electronics Engineers (IEEE) 802 standards (802.3, 802.11, and 802.15.1) that defines the protocol and frame formats for bridging, Ethernet, wireless local area network (LAN), and Bluetooth personal area network (PAN). It is the lower sublayer of the Data Link Layer of the Open Systems Interconnection (OSI) model.
Media Access Control (MAC)
Which of the following is NOT a Gigabit Ethernet Physical Layer function?
Media access control (MAC) address assignments
A flexible and reliable open-source server application that uses Structured Query Language (SQL) for accessing and managing relational database information. Used as an alternative to proprietary database systems, MySQL can be customized to suit the needs of the user.
MySQL
With what SONET standard is 10GbE compatible?
OC-192
With what synchronous optical network (SONET) standard is 10GBase-EW/LW/SW compatible?
OC-192.
A 64-bit technology introduced by Intel to define a local bus system for a computer. A bus connects the central processor of a PC with the video controller, disk controller, hard drives, and memory. PCI is capable of transferring data across a PC bus at very high rates.
Peripheral Component Interconnect (PCI) Bus
Why do routers take more time to process frames than Layer 3 switches do? (select two)
Routers check both frame addresses and packet addresses. Routers make decisions in software; switches make decisions in hardware.
A network dedicated to providing standalone or clustered data storage accessible to multiple clients and/or servers. SANs are usually placed on their own high-speed, low latency network segment or subnet.
Storage Area Network (SAN)
How are store-and-forward Ethernet switches different from cut-through switches?
Store-and-forward switches are more accurate, but cut-through switches are faster.
How are store-and-forward switches different than cut-through switches?
Store-and-forward switches are more accurate, but cut-through switches are faster.
Virtual local area networks (VLAN) are typically implemented using which type of device?
Switch
What is the advantage of a switch over a standard hub? (choose two)
Switches can improve network performance by keeping individual workgroup traffic local. Switches isolate traffic per port
The IEEE 802.1Q standard extends the maximum Ethernet frame size by 4 bytes to identify frames intended for a virtual local area network (VLAN). This information is inserted between the source address and the Ethernet type fields. The first 2 bytes make up the TPID, which identifies the frame as a tagged frame containing IEEE 802.1Q data. TPID is always set to 0x8100.
Tag Protocol Identifier (TPID)
What is the difference between the frame formats of 10 Mbps Ethernet and 100 Mbps Ethernet?
The 10 Mbps Ethernet frame is exactly the same and contains the same fields as the 100 Mbps frame.
A small company's chief technology officer (CTO) wants to upgrade their existing network to Fast Ethernet. The existing network consists of the following:• 10/100 Network interface cards (NIC) in the server and workstations• 10/100 Hubs• Category 3 and 5E cabling• A 10/100 routerWhich component must be upgraded to support Fast Ethernet?
The Category 3 cabling
A user's personal computer (PC) is connected to a virtual local area network (VLAN) trunk link. What will most likely happen as the switch forwards tagged frames to the PC?
The switch will identify improperly tagged frames as invalid and drop them.
How does IEEE 802.3 frame format differ from Ethernet Version 2 frame format?
The type field is replaced with the length field.
Which statement is true concerning 10 Gigabit Ethernet (10GbE) Multi-Source Agreements (MSA)?
They describe vendor-developed pluggable optics for interconnecting 10GbE devices.
What is the purpose of the frame check sequence (FCS) field? (Choose two)
To ensure the Ethernet frame does not get processed if an error has occurred. To check the Ethernet frame for errors using a cyclic redundancy check (CRC).
What is the primary reason to build a virtual local area network (VLAN)?
To minimize broadcast traffic.
What is the preamble used for?
To synchronize Ethernet network interface cards (NIC) so the bits that make up the frames are received correctly.
What is the primary reason an Ethernet network interface card (NIC) transmits a jamming message?
To warn other stations that a collision has been detected.
Virtual local area networks (VLAN) can be created using a variety of switch vendor products in the same network. True or False
True
The IEEE 802.1Q standard specifies the VLAN (virtual local area network) Identifier (VID) as part of the last 2 bytes of the 4-byte VLAN tag. The VID contains unique values to identify the VLAN to which the Ethernet frame belongs.
VLAN Identifier (VID)
provide broadcast containment and form separate virtual workgroup LANs.
VLANs
A technology that consists of telephone signals transmitted as Internet protocol (IP) packets.
Voice over Internet Protocol (VoIP)
Used by Internet Protocol (IP), such as in transmission control protocol/Internet protocol (TCP/IP, for address resolution. Address resolution refers to the ability of a station to resolve another station's media access control (MAC) (hardware) address given its IP address.
address resolution protocol (ARP)
A value that records the number of times an Ethernet network interface card (NIC) has attempted to transmit the same frame. The NIC discards a frame after 16 consecutive collisions occur for the same transmission attempt.
attempt counter
The maximum number of times (16) that an Ethernet network interface card (NIC) attempts to retransmit a frame after a collision.
attempt limit
The backbone of a network is the portion of the network that carries the most significant traffic. It is also the part of the network that connects many local area networks (LAN) or subnetworks together to form a network. High-speed switches are often used to form network backbones. In this configuration, switches often limit local traffic from the backbone to reduce congestion.
backbone
When a collision occurs on an Ethernet segment, all transmitting nodes "back off" and do not transmit for a random length of time before attempting to transmit again. This is referred to as the backoff time. This random time selection interval reduces the likelihood that both stations will attempt to retransmit at the same time.
backoff time
A hardware device that connects several local area networks (LAN) or LAN segments. Wireless bridges often create a connection between a wired and a wireless LAN. A bridge operates at the Data Link Layer of the Open Systems Interconnection (OSI) model.
bridge
The term broadcast is used in several different ways in communications and networks. With respect to local area networks (LAN), the term refers to information (frames) sent to all devices on the physical segment. For example, a bus topology, in which a common cable is used to connect devices, is considered a bus topology. Another common use of the word broadcast relates to frames. Broadcast frames or packets contain a special destination address (DA) that instructs all devices on the network to receive and process the frame.
broadcast
The area of a network that receives broadcast messages from any device within the network segment. Routers and Layer 3 switches are used to separate broadcast domains by keeping traffic within a network segment.
broadcast domain
A set of rules determining how network devices respond when two devices attempt to use a data channel simultaneously (called a collision). This standard, used in half-duplex Ethernet networks, enables devices to listen for collisions. After detecting a collision, a device waits a random delay time and then attempts to retransmit the message. If the device detects a collision again, it waits twice as long to try to retransmit the message. This is known as exponential backoff.
carrier sense multiple access with collision detection (CSMA/CD)
A mathematical function is applied to the bits of a file or frame. The output of that calculation is called the checksum. A checksum can be appended to the data unit as a simple error-detection method. The receiving node applies the same mathematical function to the received data and compares the results to the checksum to see whether all bits have arrived without modification. If the numbers match, the transmission was probably correct. The frame check sequence (FCS) field in the trailer of an Ethernet frames is an example of a checksum value.
checksum
A 3-bit field within an Ethernet frame that identifies and marks network traffic so that the traffic can be differentiated and segregated into classes to allow different types of traffic to be prioritized over other types.
class of service (CoS)
A network topology that uses a multiport device, such as a switch or router, to carry traffic between network segments or subnets.
collapsed backbone
Occurs in an Ethernet network when two frames are put onto the physical medium at the same time and overlap fully or partially. When a collision occurs, the data on the physical segment is no longer valid
collision
In an Ethernet network, a collision domain is a portion of the network where all nodes receive every frame transmitted by all other nodes and compete for access to the shared medium. A bus, hub, or group of interconnected hubs forms a single collision domain.
collision domain
A method of medium access where all nodes compete for access and the first one to gain access can transmit data.
contention
A network that supports both data and voice communication, or data and multimedia.
converged network
The mathematical process used to check the accuracy of data transmitted across a network. Before transmitting a block of data, the sending station performs a calculation on the data block and appends the resulting value to the end of the block. The receiving station takes the data and the CRC value, and performs the same calculation to check the accuracy of the data.
cyclic redundancy check (CRC)
Also known as modified cut-through switching, this switching method reads the first 64 bytes of data to verify that it has not been involved in a collision and truncated. It then forwards the frame to the destination if there are no problems or drops it if corruption was detected. The transmission rate is the same, regardless of the frame size.
fragment-free switching
A unit of information transmitted across a data link. Ethernet frames, for example, are frames generated by an Ethernet network interface controller (NIC).
frame
Contained in a data field of the frame trailer, is a 4-byte cyclic redundancy check (CRC) value used to check for damaged frames. The FCS can only detect the most basic types of errors, such as a bit that has been changed from a 1 to a 0.
frame check sequence (FCS)
A technology designed to move data across a wide area network (WAN) at speeds of 56 Kbps to 1.5 Mbps. Frame relay was originally intended only for data communications, not voice or video. Transmission errors are detected but not corrected (the frame is discarded). Physically, a frame relay access device (FRAD) is a box that connects to three or more high-speed links and routes data traffic between them.
frame relay
The minimum time interval between Ethernet frames. After a node detects the end of a frame, it must wait this amount of time before attempting to transmit.
interframe gap
A fiber-optic cable thick enough to transmit several different optical signal modes simultaneously. Each signal is separated by the others by being reflected at different angles within the fiber. See single-mode fiber (SMF).
multimode fiber (MMF)
One billionth of a meter, or 1 x 10^9. See wavelength.
nanometer (nm)
Any condition, such as electrical interference, that destroys signal integrity. Noise can be caused by many electromagnetic sources, such as radio transmissions, electrical cables, electric motors, lighting dimmers, or bad cable connections.
noise
Also called class of service, it refers to a set of techniques for assigning priority to packets or frames from a given application as it travels across a network. QoS settings can offer priority service to time-sensitive information like voice and video. In the context of the Open Systems Interconnection (OSI) reference model, users of the Network Layer specify QoS parameters as part of a request for a communication channel. These parameters define different levels of service based on the requirements of an application. For example, an interactive application that requires good response time would specify high QoS values for connection establishment delay, throughput, transit delay, and connection priority. However, a file transfer application requires reliable, error-free data transfer more than it needs a prompt connection, thus it would request high QoS parameters for residual error rate/probability.
quality of service (QoS)
A Layer 3 device with several ports that can each connect to a network or another router. The router examines the logical network address of each packet, then uses its internal routing table to forward the packet to the routing port associated with the best path to the packet's destination. If the packet is addressed to a network that is not connected to the router, the router forwards the packet to another router that is closer to its final destination. Each router, in turn, evaluates each packet and then either drops, delivers, or forwards the packet to another router.
router
Signal reflection refers to the situation where part, or all, of an electrical signal bounces back from an improperly made cable connection. This effect creates signal noise that can be misinterpreted as frame collisions.
signal reflection
A thin fiber-optic cable that can transmit only one optical signal. Because there is no chance the signal can interfere with any other signal, and laser light not light emitting diode (LED) is used, single-mode fiber can transmit signals over much longer distances than multimode fiber (MMF). See multimode fiber (MMF).
single-mode fiber (SMF)
Follows the Ethernet preamble and is a byte that ends with two consecutive one bits. These bits synchronize all the network interface controllers (NIC) on a local area network (LAN) to receive the Ethernet frame.
start of frame delimiter (SOFD)
An internetworking device that operates at the Data Link Layer or Network and Data Link layers of the Open Systems Interconnection (OSI) reference model. A switch can connect local area networks (LAN) or segments of the same media access type. A switch dedicates its entire bandwidth to each frame it switches.
switch
An encrypted connection over a shared network that behaves like a dedicated link. VPNs are created using a technique called "tunneling," which uses encryption to transmit data packets across a public network, such as the Internet or other commercially available network, in a private "tunnel" that simulates a point-to-point connection. The tunnels of a VPN can be encrypted for additional security.
virtual private network (VPN)
The distance between one crest of a wave and the next is referred to as the wavelength. Light wavelengths are measured in nanometers (nm), or billionths of a meter. Each nanometer is 1 x 10^9 meter.
wavelength
