CCNA 1 v7.0 Modules 4 - 7: Ethernet Concepts Exam

Match the situation with the appropriate use of network media.

* copper cables - horizontal cabling structure / desktop PCs in an enterprise office *fiber optic - backbone cabling in an enterprise / long-haul networks *wireless - guest access in a coffee shop / waiting rooms in a hospital

Refer to the exhibit. What is the destination MAC address of the Ethernet frame as it leaves the web server if the final destination is PC1? 00-60-2F-3A-07-AA 00-60-2F-3A-07-BB 00-60-2F-3A-07-CC 00-60-2F-3A-07-DD

00-60-2F-3A-07-CC Explanation: The destination MAC address is used for local delivery of Ethernet frames. The MAC (Layer 2) address changes at each network segment along the path. As the frame leaves the web server, it will be delivered by using the MAC address of the default gateway.

Which is a multicast MAC address? FF-FF-FF-FF-FF-FF 5C-26-0A-4B-19-3E 01-00-5E-00-00-03 00-26-0F-4B-00-3E

01-00-5E-00-00-03 Explanation: Multicast MAC addresses begin with the special value of 01-00-5E.

Refer to the exhibit. The PC is connected to the console port of the switch. All the other connections are made through FastEthernet links. Which types of UTP cables can be used to connect the devices?​ 1 - rollover, 2 - crossover, 3 - straight-through 1 - rollover, 2 - straight-through, 3 - crossover 1 - crossover, 2 - straight-through, 3 - rollover 1 - crossover, 2 - rollover, 3 - straight-through

1 - rollover, 2 - straight-through, 3 - crossover Explanation: A straight-through cable is commonly used to interconnect a host to a switch and a switch to a router. A crossover cable is used to interconnect similar devices together like switch to a switch, a host to a host, or a router to a router. If a switch has the MDIX capability, a crossover could be used to connect the switch to the router; however, that option is not available. A rollover cable is used to connect to a router or switch console port.

advantage of store-and-forward switching discarding frames with errors reduces the amount of bandwidth

A big advantage of store-and-forward switching is that the switch determines whether a frame has errors before propagating the frame. When an error is detected in a frame, the switch discards the frame. Discarding frames with errors reduces the amount of bandwidth consumed by corrupt data. Store-and-forward switching is required for quality of service (QoS) analysis on converged networks where frame classification for traffic prioritization is necessary. For example, voice over IP (VoIP) data streams need to have priority over web-browsing traffic.

Which two functions are performed at the LLC sublayer of the OSI data link layer? (Choose two.) Adds Layer 2 control information to network protocol data. Enables IPv4 and IPv6 to utilize the same network interface and media. Provides data link layer addressing. Implements a trailer to detect transmission errors. Provides synchronization between source and target nodes.

Adds Layer 2 control information to network protocol data. Enables IPv4 and IPv6 to utilize the same network interface and media

Which two functions are performed at the LLC sublayer of the OSI data link layer? (Choose two.) Adds Layer 2 control information to network protocol data. Places information in the frame that identifies which network layer protocol is being used for the frame. Performs data encapsulation. Controls the NIC responsible for sending and receiving data on the physical medium. Integrates various physical technologies

Adds Layer 2 control information to network protocol data. Places information in the frame that identifies which network layer protocol is being used for the frame.

Which statement is true about the CSMA/CD access method that is used in Ethernet? When a device hears a carrier signal and transmits, a collision cannot occur. All network devices must listen before transmitting. A jamming signal causes only devices that caused the collision to execute a backoff algorithm. Devices involved in a collision get priority to transmit after the back-off period.

All network devices must listen before transmitting Explanation: Legacy bus-topology Ethernet LAN uses CSMA/CD as network media access control protocol. It works by detecting a collision in the medium and backing off (after transmitting a jam signal) as necessary. When one host wants to transmit a frame, it listens on the medium to check if the medium is busy. After it senses that no one else is transmitting, the host starts transmitting the frame, it also monitors the current level to detect a collision. If it detects a collision, it transmits a special jam signal so that all other hosts can know there was a collision. The other host will receive this jam signal and stop transmitting. After this, both hosts enter an exponential back-off phase and retry transmission.

When the store-and-forward method of switching is in use, what part of the Ethernet frame is used to perform an error check? CRC in the trailer source MAC address in the header destination MAC address in the header protocol type in the header

CRC in the trailer Explanation: When the store-and-forward switching method is used, the switch receives the complete frame before forwarding it on to the destination. The cyclic redundancy check (CRC) part of the trailer is used to determine if the frame has been modified during transit.​​ In contrast, a cut-through switch forwards the frame once the destination Layer 2 address is read. Two types of cut-through switching methods are fast-forward and fragment-free.

Which two functions are performed at the LLC sublayer of the OSI data link layer? (Choose two.) Enables IPv4 and IPv6 to utilize the same network interface and media. Places information in the frame that identifies which network layer protocol is being used for the frame. Integrates various physical technologies. Implements a process to delimit fields within a Layer 2 frame. Controls the NIC responsible for sending and receiving data on the physical medium.

Enables IPv4 and IPv6 to utilize the same network interface and media.* Places information in the frame that identifies which network layer protocol is being used for the frame.*

Which statement describes an extended star topology? End devices connect to a central intermediate device, which in turn connects to other central intermediate devices. End devices are connected together by a bus and each bus connects to a central intermediate device. Each end system is connected to its respective neighbor via an intermediate device. All end and intermediate devices are connected in a chain to each other.

End devices connect to a central intermediate device, which in turn connects to other central intermediate devices.* Explanation: In an extended star topology, central intermediate devices interconnect other star topologies.

What are three ways that media access control is used in networking? Ethernet utilizes CSMA/CD. Media access control provides placement of data frames onto the media. Contention-based access is also known as deterministic. 802.11 utilizes CSMA/CD. Data link layer protocols define the rules for access to different media. Networks with controlled access have reduced performance due to data collisions.

Ethernet utilizes CSMA/CD Media access control provides placement of data frames onto the media Data link layer protocols define the rules for access to different media Explanation: Wired Ethernet networks use CSMA/CD for media access control. IEEE 802.11 wireless networks use CSMA/CA, a similar method. Media access control defines the way data frames get placed on the media. The controlled access method is deterministic, not a contention-based access to networks. Because each device has its own time to use the medium, controlled access networks such as legacy Token Ring do not have collisions.

Open the PT Activity. Perform the tasks in the activity instructions and then answer the question. Which port does Switch0 use to send frames to the host with the IPv4 address 10.1.1.5? Fa0/5 Fa0/9 Fa0/1 Fa0/11

Fa0/11 Explanation: Issuing the command ipconfig /all from the PC0 command prompt displays the IPv4 address and MAC address. When the IPv4 address 10.1.1.5 is pinged from PC0, the switch stores the source MAC address (from PC0) along with the port to which PC0 is connected. When the destination reply is received, the switch takes the destination MAC address and compares to MAC addresses stored in the MAC address table. Issuing the show mac-address-table on the PC0 Terminal application displays two dynamic MAC address entries. The MAC address and port entry that does not belong to PC0 must be the MAC address and port of the destination with the IPv4 address 10.1.1.5.

Which two fields or features does Ethernet examine to determine if a received frame is passed to the data link layer or discarded by the NIC? (choose 2) auto-MDIX CEF Frame Check Sequence minimum frame size source MAC address

Frame Check Sequence / minimum frame size Explanation: An Ethernet frame is not processed and is discarded if it is smaller than the minimum (64 bytes) or if the calculated frame check sequence (FCS) value does not match the received FCS value. Auto-MDIX (automatic medium-dependent interface crossover) is Layer 1 technology that detects cable straight-through or crossover types. The source MAC address is not used to determine how the frame is received. CEF (Cisco Express Forwarding) is a technology used to expedite Layer 3 switching.

Which two functions are performed at the MAC sublayer of the OSI data link layer? (2)

Implements a trailer to detect transmission errors.* / Controls the NIC responsible for sending and receiving data on the physical medium.*

What is the auto-MDIX feature? It enables a device to automatically configure an interface to use a straight-through or a crossover cable. It enables a device to automatically configure the duplex settings of a segment. It enables a device to automatically configure the speed of its interface. It enables a switch to dynamically select the forwarding method.

It enables a device to automatically configure an interface to use a straight-through or a crossover cable.*

What are two characteristics of fiber-optic cable?

It is not affected by EMI or RFI(crosstalk) / It is more expensive than UTP cabling is

Which two statements describe the services provided by the data link layer?

It manages the access of frames to the network media / It packages various Layer 3 PDUs into a frame format that is compatible with the network interface

What is a characteristic of the LLC sublayer? It provides the logical addressing required that identifies the device. It provides delimitation of data according to the physical signaling requirements of the medium. It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media. It defines software processes that provide services to the physical layer.

It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.* Explanation: The Logical Link Control (LLC) defines the software processes that provide services to the network layer protocols. The information is placed by LLC in the frame and identifies which network layer protocol is being used for the frame. This information allows multiple Layer 3 protocols, such as IPv4 and IPv6, to utilize the same network interface and media.

Which two statements describe features or functions of the logical link control sublayer in Ethernet standards? Logical link control is implemented in software. Logical link control is specified in the IEEE 802.3 standard. The LLC sublayer adds a header and a trailer to the data. The data link layer uses LLC to communicate with the upper layers of the protocol suite. The LLC sublayer is responsible for the placement and retrieval of frames on and off the media.

Logical link control is implemented in software. / The data link layer uses LLC to communicate with the upper layers of the protocol suite. Explanation: Logical link control is implemented in software and enables the data link layer to communicate with the upper layers of the protocol suite. Logical link control is specified in the IEEE 802.2 standard. IEEE 802.3 is a suite of standards that define the different Ethernet types. The MAC (Media Access Control) sublayer is responsible for the placement and retrieval of frames on and off the media. The MAC sublayer is also responsible for adding a header and a trailer to the network layer protocol data unit (PDU).

Which two functions are performed at the MAC sublayer of the OSI data link layer?

Provides a mechanism to allow multiple devices to communicate over a shared medium.*/Controls the NIC responsible for sending and receiving data on the physical medium.*

cut-through vs store-and-forward switching

Store-and-forward switching: With this frame forwarding method, the switch receives the entire frame and computes the CRC. The switch uses a mathematical formula, based on the number of bits (1s) in the frame, to determine whether the received frame has an error. If the CRC is valid, the switch looks up the destination address, which determines the outgoing interface. Then the frame is forwarded out the correct port. Cut-through switching: With this frame forwarding method, the switch forwards the frame before it is entirely received. At a minimum, the destination address of the frame must be read before the frame can be forwarded. Some switches are configured to perform cut-through switching on a per-port basis until a user-defined error threshold is reached, and then they automatically change to store-and-forward. When the error rate falls below the threshold, the port automatically changes back to cut-through switching.

What action will occur if a host receives a frame with a destination MAC address it does not recognize? The host will discard the frame. The host sends the frame to the switch to update the MAC address table. The host forwards the frame to the router. The host forwards the frame to all other hosts.

The host will discard the frame

What action will occur if a host receives a frame with a destination MAC address of FF:FF:FF:FF:FF:FF? The host will process the frame. The host forwards the frame to the router. The host sends the frame to the switch to update the MAC address table. The host forwards the frame to all other hosts.

The host will process the frame.

A network administrator is connecting two modern switches using a straight-through cable. The switches are new and have never been configured. Which three statements are correct about the final result of the connection? (choose 3) The link between the switches will work at the fastest speed that is supported by both switches. The link between switches will work as full-duplex. If both switches support different speeds, they will each work at their own fastest speed. The auto-MDIX feature will configure the interfaces eliminating the need for a crossover cable. The connection will not be possible unless the administrator changes the cable to a crossover cable. The duplex capability has to be manually configured because it cannot be negotiated.

The link between the switches will work at the fastest speed that is supported by both switches. / The link between switches will work as full-duplex. /The auto-MDIX feature will configure the interfaces eliminating the need for a crossover cable.* Explanation: Modern switches can negotiate to work in full-duplex mode if both switches are capable. They will negotiate to work using the fastest possible speed and the auto-MDIX feature is enabled by default, so a cable change is not needed.

During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network? An IP address is added. The logical address is added. The physical address is added. The process port number is added.

The physical address is added. Explanation: The Ethernet frame includes the source and destination physical address. The trailer includes a CRC value in the Frame Check Sequence field to allow the receiving device to determine if the frame has been changed (has errors) during the transmission.

What action will occur if a switch receives a frame with the destination MAC address 01:00:5E:00:00:D9? The switch forwards it out all ports except the ingress port. The switch does not forward the frame. The switch sends the frame to a connected router because the destination MAC address is not local. The switch shares the MAC address table entry with any connected switches.

The switch forwards it out all ports except the ingress port.

What action will occur if a switch receives a frame with the destination MAC address FF:FF:FF:FF:FF:FF? The switch forwards it out all ports except the ingress port. The switch shares the MAC address table entry with any connected switches. The switch does not forward the frame. The switch sends the frame to a connected router because the destination MAC address is not local.

The switch forwards it out all ports except the ingress port.*

What action will occur if a switch receives a frame and does have the source MAC address in the MAC table? The switch refreshes the timer on that entry. The switch shares the MAC address table entry with any connected switches. The switch does not forward the frame. The switch sends the frame to a connected router because the destination MAC address is not local.

The switch refreshes the timer on that entry.

What are two examples of the cut-through switching method (choose 2) store-and-forward switching fast-forward switching CRC switching fragment-free switching QOS switching

The two variants of cut-through switching are: fast-forward switching / fragment-free switching Fast-forward switching offers the lowest level of latency. With fast-forward switching, the switch immediately forwards a packet after reading the destination address. Fast-forward switching is the typical cut-through method of switching. In fragment-free switching, the switch stores the first 64 bytes of the frame before forwarding. Fragment-free switching is a compromise between the high latency and high integrity of store-and-forward switching and the low latency and reduced integrity of fast-forward switching.

Refer to the exhibit. What is wrong with the displayed termination? The woven copper braid should not have been removed. The wrong type of connector is being used. The untwisted length of each wire is too long. The wires are too thick for the connector that is used.

The untwisted length of each wire is too long. Explanation: When a cable to an RJ-45 connector is terminated, it is important to ensure that the untwisted wires are not too long and that the flexible plastic sheath surrounding the wires is crimped down and not the bare wires. None of the colored wires should be visible from the bottom of the jack.

Why are two strands of fiber used for a single fiber optic connection?

They allow for full-duplex connectivity.*

Which statement describes a characteristic of the frame header fields of the data link layer?

They vary depending on protocols. Explanation: All data link layer protocols encapsulate the Layer 3 PDU within the data field of the frame. However, the structure of the frame and the fields that are contained in the header vary according to the protocol. Different data link layer protocols may use different fields, like priority/quality of service, logical connection control, physical link control, flow control, and congestion control.

What type of communication rule would best describe CSMA/CD? message encoding flow control access method message encapsulation

access method Explanation: Carrier sense multiple access collision detection (CSMA/CD) is the access method used with Ethernet. The access method rule of communication dictates how a network device is able to place a signal on the carrier. CSMA/CD dictates those rules on an Ethernet network and CSMA/CA dictates those rules on an 802.11 wireless LAN.

What OSI physical layer term describes the physical medium for microwave transmissions? air goodput latency throughput

air

What OSI physical layer term describes the capacity at which a medium can carry data? bandwidth throughput latency goodput

bandwidth

What OSI physical layer term describes the physical medium which uses electrical pulses? copper cable fiber-optic cable air goodput

copper cable

Which two devices commonly affect wireless networks?

cordless phones / microwaves

What is a primary role of the Physical layer in transmitting data on the network?

create the signals that represent the bits in each frame on to the media. Explanation: The OSI physical layer provides the means to transport the bits that make up a frame across the network media. This layer accepts a complete frame from the data link layer and encodes it as a series of signals that are transmitted to the local media.

In addition to the cable length, what two factors could interfere with the communication carried over UTP cables?

crosstalk / electromagnetic interference

What is contained in the trailer of a data-link frame?

error detection The trailer in a data-link frame contains error detection information that is pertinent to the frame included in the FCS field. The header contains control information, such as the addressing, while the area that is indicated by the word "data" includes the data, transport layer PDU, and the IP header.

Which switching method has the lowest level of latency? cut-through store-and-forward fragment-free fast-forward

fast-forward Explanation: Fast-forward switching begins to forward a frame after reading the destination MAC address, resulting in the lowest latency. Fragment-free reads the first 64 bytes before forwarding. Store-and-forward has the highest latency because it reads the entire frame before beginning to forward it. Both fragment-free and fast-forward are types of cut-through switching.

What OSI physical layer term describes the physical medium that uses the propagation of light? fiber-optic cable goodput latency throughput

fiber-optic cable

Which advantage does the store-and-forward switching method have compared with the cut-through switching method? collision detecting frame error checking faster frame forwarding frame forwarding using IPv4 Layer 3 and 4 information

frame error checking Explanation: A switch using the store-and-forward switching method performs an error check on an incoming frame by comparing the FCS value against its own FCS calculations after the entire frame is received. In comparison, a switch using the cut-through switching method makes quick forwarding decisions and starts the forwarding process without waiting for the entire frame to be received. Thus a switch using cut-through switching may send invalid frames to the network. The performance of store-and-forward switching is slower compared to cut-through switching performance. Collision detection is monitored by the sending device. Store-and-forward switching does not use IPv4 Layer 3 and 4 information for its forwarding decisions.

Which media communication type does not require media arbitration in the data link layer? deterministic half-duplex full-duplex controlled access

full-duplex Explanation: Half-duplex communication occurs when both devices can both transmit and receive on the medium but cannot do so simultaneously. Full-duplex communication occurs when both devices can transmit and receive on the medium at the same time and therefore does not require media arbitration. Half-duplex communication is typically contention-based, whereas controlled (deterministic) access is applied in technologies where devices take turns to access the medium.

What OSI physical layer term describes the measure of usable data transferred over a given period of time? latency bandwidth throughput goodput

goodput

What makes fiber preferable to copper cabling for interconnecting buildings? (choose 3) greater distances per cable run lower installation cost limited susceptibility to EMI/RFI durable connections greater bandwidth potential easily terminated

greater distances per cable run/limited susceptibility to EMI/RFI , greater bandwidth potential Explanation: Optical fiber cable transmits data over longer distances and at higher bandwidths than any other networking media. Unlike copper wires, fiber-optic cable can transmit signals with less attenuation and is completely immune to EMI and RFI.

What is one advantage of using the cut-through switching method instead of the store-and-forward switching method? has a positive impact on bandwidth by dropping most of the invalid frames makes a fast forwarding decision based on the source MAC address of the frame has a lower latency appropriate for high-performance computing applications​ provides the flexibility to support any mix of Ethernet speeds

has a lower latency appropriate for high-performance computing applications Explanation: Cut-through switching provides lower latency switching for high-performance computing (HPC) applications. Cut-through switching allows more invalid frames to cross the network than store-and-forward switching. The cut-through switching method can make a forwarding decision as soon as it looks up the destination MAC address of the frame.

Which three basic parts are common to all frame types supported by the data link layer? header type field MTU size data trailer CRC value

header / data / trailer Explanation: The data link protocol is responsible for NIC-to-NIC communications within the same network. Although there are many different data link layer protocols that describe data link layer frames, each frame type has three basic parts: Header Data Trailer

What OSI physical layer term describes the amount of time, including delays, for data to travel from one point to another? latency bandwidth throughput goodput

latency

What does the term "attenuation" mean in data communication? loss of signal strength as distance increases time for a signal to reach its destination leakage of signals from one cable pair to another strengthening of a signal by a networking device

loss of signal strength as distance increases* Explanation: Data is transmitted on copper cables as electrical pulses. A detector in the network interface of a destination device must receive a signal that can be successfully decoded to match the signal sent. However, the farther the signal travels, the more it deteriorates. This is referred to as signal attenuation.

What OSI physical layer term describes the process by which one wave modifies another wave? modulation IEEE EIA/TIA air

modulation

A network team is comparing physical WAN topologies for connecting remote sites to a headquarters building. Which topology provides high availability and connects some, but not all, remote sites?

partial mesh Explanation: Partial mesh topologies provide high availability by interconnecting multiple remote sites, but do not require a connection between all remote sites. A mesh topology requires point-to-point links with every system being connected to every other system. A point-to-point topology is where each device is connected to one other device. A hub and spoke uses a central device in a star topology that connects to other point-to-point devices.

A Layer 2 switch is used to switch incoming frames from a 1000BASE-T port to a port connected to a 100Base-T network. Which method of memory buffering would work best for this task? port-based buffering level 1 cache buffering shared memory buffering fixed configuration buffering

shared memory buffering Port-based memory buffering - Frames are stored in queues that are linked to specific incoming and outgoing ports. - A frame is transmitted to the outgoing port only when all the frames ahead in the queue have been successfully transmitted. - It is possible for a single frame to delay the transmission of all the frames in memory because a destination port is busy. This delay occurs even if the other frames could be transmitted to open destination ports. Shared memory buffering -All frames are deposited into a common memory buffer shared by all switch ports, and the amount of buffer memory required by a port is dynamically allocated. -The frames in the buffer are dynamically linked to the destination port, enabling a packet to be received on one port and then transmitted on another port, without moving it to a different queue. Shared memory buffering results in the ability to store larger frames with potentially fewer dropped frames. This is important with asymmetric switching, which allows for different data rates on different ports, such as when connecting a server to a 10 Gbps switch port and PCs to 1 Gbps ports. https://www.ciscopress.com/articles/article.asp?p=3089352&seqNum=7

What three items are contained in an Ethernet header and trailer? source IP address source MAC address destination IP address destination MAC address error-checking information

source MAC address / destination MAC address / error-checking information Explanation: Layer 2 headers contain the following: Frame start and stop indicator flags at the beginning and end of a frame Addressing - for Ethernet networks this part of the header contains source and destination MAC addresses Type field to indicate what Layer 3 protocol is being used Error detection to determine if the frame arrived without error

Which switching method uses the CRC value in a frame? cut-through fast-forward fragment-free store-and-forward

store-and-forward Explanation: When the store-and-forward switching method is used, the switch receives the complete frame before forwarding it on to the destination. The cyclic redundancy check (CRC) part of the trailer is used to determine if the frame has been modified during transit.​​ In contrast, a cut-through switch forwards the frame once the destination Layer 2 address is read. Two types of cut-through switching methods are fast-forward and fragment-free.

Which frame forwarding method receives the entire frame and performs a CRC check to detect errors before forwarding the frame? cut-through switching store-and-forward switching fragment-free switching fast-forward switching

store-and-forward switching Explanation: Fast-forward and fragment-free switching are variations of cut-through switching, which begins to forward the frame before the entire frame is received.

A network administrator is measuring the transfer of bits across the company backbone for a mission critical financial application. The administrator notices that the network throughput appears lower than the bandwidth expected. Which three factors could influence the differences in throughput?

the amount of traffic that is currently crossing the network / the type of traffic that is crossing the network / the latency that is created by the number of network devices that the data is crossing

What is the auto-MDIX feature on a switch? the automatic configuration of an interface for 10/100/1000 Mb/s operation the automatic configuration of an interface for a straight-through or a crossover Ethernet cable connection the automatic configuration of full-duplex operation over a single Ethernet copper or optical cable the ability to turn a switch interface on or off accordingly if an active connection is detected

the automatic configuration of an interface for a straight-through or a crossover Ethernet cable connection Explanation: The auto-MDIX enables a switch to use a crossover or a straight-through Ethernet cable to connect to a device regardless of the device on the other end of the connection.

Which characteristic describes crosstalk?

the distortion of the transmitted messages from signals carried in adjacent wires*

With the use of unshielded twisted-pair copper wire in a network, what causes crosstalk within the cable pairs?

the magnetic field around the adjacent pairs of wire

What OSI physical layer term describes the measure of the transfer of bits across a medium over a given period of time? throughput bandwidth latency goodput

throughput

What is the purpose of the FCS field in a frame? to obtain the MAC address of the sending node to verify the logical address of the sending node to compute the CRC header for the data field to determine if errors occurred in the transmission and reception

to determine if errors occurred in the transmission and reception Explanation: The FCS field in a frame is used to detect any errors in the transmission and receipt of a frame. This is done by comparing the CRC value within the frame against a computed CRC value of the frame. If the two values do not match, then the frame is discarded.

What is the function of the CRC value that is found in the FCS field of a frame?

to verify the integrity of the received frame

What is the purpose of the OSI physical layer?

transmitting bits across the local media*

Which procedure is used to reduce the effect of crosstalk in copper cables?

twisting opposing circuit wire pairs together*

What are two actions performed by a Cisco switch? building a routing table that is based on the first IP address in the frame header using the source MAC addresses of frames to build and maintain a MAC address table forwarding frames with unknown destination IP addresses to the default gateway utilizing the MAC address table to forward frames via the destination MAC address examining the destination MAC address to add new entries to the MAC address table

using the source MAC addresses of frames to build and maintain a MAC address table / utilizing the MAC address table to forward frames via the destination MAC address Explanation: Important actions that a switch performs are as follows: When a frame comes in, the switch examines the Layer 2 source address to build and maintain the Layer 2 MAC address table. It examines the Layer 2 destination address to determine how to forward the frame. When the destination address is in the MAC address table, then the frame is sent out a particular port. When the address is unknown, the frame is sent to all ports that have devices connected to that network.