Chapter 5: Ethernet
What is the Layer 2 multicast MAC address that corresponds to the Layer 3 IPv4 multicast address 224.139.34.56?
01-00-5E-0B-22-38*
Fill in the blank. The binary number 0000 1010 can be expressed as __________________________________ in hexadecimal.
0A
What are two features of ARP? (Choose two.)
1) *If a host is ready to send a packet to a local destination device and it has the IP address but not the MAC address of the destination, it generates an ARP broadcast.* 2) An ARP request is sent to all devices on the Ethernet LAN and contains the IP address of the destination host and its multicast MAC address. 3) When a host is encapsulating a packet into a frame, it refers to the MAC address table to determine the mapping of IP addresses to MAC addresses. 4) *If a device receiving an ARP request has the destination IPv4 address, it responds with an ARP reply.* 5) If no device responds to the ARP request, then the originating node will broadcast the data packet to all devices on the network segment.
Which two functions or operations are performed by the MAC sublayer? (Choose two.)
1) *It is responsible for Media Access Control. 2) It performs the function of NIC driver software. Correct! 3) *It adds a header and trailer to form an OSI Layer 2 PDU. 4) It handles communication between upper and lower layers. 5) It adds control information to network protocol layer data.
Which two statements describe features or functions of the logical link control sublayer in Ethernet standards? (Choose two.)
1) *Logical link control is implemented in software.* 2) The LLC sublayer interacts directly with the NIC driver software. 3) *The data link layer uses LLC to communicate with the upper layers of the protocol suite.* 4) The LLC sublayer is responsible for the placement and retrieval of frames on and off the media. 5) Logical link control is specified in the IEEE 802.3 standard.
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 three.)
1) *The auto-MDIX feature will configure the interfaces eliminating the need for a crossover cable.* 2) The connection will not be possible unless the administrator changes the cable to a crossover cable. 3) The duplex capability has to be manually configured because it cannot be negotiated. 4) If both switches support different speeds, they will each work at their own fastest speed. 5) *The link between switches will work as full-duplex.* 6) *The link between the switches will work at the fastest speed that is supported by both switches.*
Which two statements describe features or functions of the logical link control sublayer in Ethernet standards? (Choose two.)
1) *The data link layer uses LLC to communicate with the upper layers of the protocol suite. 2) *Logical link control is implemented in software. 3) Logical link control is specified in the IEEE 802.3 standard. 4) The LLC sublayer is responsible for the placement and retrieval of frames on and off the media. 5) Logical link control is implemented in software.
Which statement is true about MAC addresses?
1) *The first three bytes are used by the vendor assigned OUI.* 2) MAC addresses are implemented by software. 3) The ISO is responsible for MAC addresses regulations. 4) A NIC only needs a MAC address if connected to a WAN.
Which destination address is used in an ARP request frame?
1) 0.0.0.0 2) 255.255.255.255 3) *FFFF.FFFF.FFFF* 4) 127.0.0.1 5) 01-00-5E-00-AA-23
What are the two sizes (minimum and maximum) of an Ethernet frame? (Choose two.)
1) 56 bytes 2) 64 bytes* 3) 128 bytes 4) 1024 bytes 5) 1518 bytes*
Which two statements describe a fixed configuration Ethernet switch? (Choose two.)
1) An SVI cannot be configured on the switch. 2) A fixed configuration switch may be stackable.* 3) The number of ports on the switch cannot be increased.* 4) The port density of the switch is determined by the Cisco IOS. 5) The switch cannot be configured with multiple VLANs.
Which two statements are correct about MAC and IP addresses during data transmission if NAT is not involved? (Choose two.)
1) Destination MAC addresses will never change in a frame that goes across seven routers. 2) A packet that has crossed four routers has changed the destination IP address four times. 3) *Destination and source MAC addresses have local significance and change every time a frame goes from one LAN to another.* 4) *Destination IP addresses in a packet header remain constant along the entire path to a target host.* 5) Every time a frame is encapsulated with a new destination MAC address, a new destination IP address is needed.
What statement describes Ethernet?
1) It defines the most common LAN type in the world.* 2) It is the required Layer 1 and 2 standard for Internet communication. 3) It defines a standard model used to describe how networking works. 4) It connects multiple sites such as routers located in different countries.
The ARP table in a switch maps which two types of address together?
1) Layer 3 address to a Layer 2 address* 2) Layer 3 address to a Layer 4 address 3) Layer 4 address to a Layer 2 address 4) Layer 2 address to a Layer 4 address
What are two potential network problems that can result from ARP operation? (Choose two.)
1) Multiple ARP replies result in the switch MAC address table containing entries that match the MAC addresses of hosts that are connected to the relevant switch port. 2) *Large numbers of ARP request broadcasts could cause the host MAC address table to overflow and prevent the host from communicating on the network. 3) *Manually configuring static ARP associations could facilitate ARP poisoning or MAC address spoofing. 4) On large networks with low bandwidth, multiple ARP broadcasts could cause data communication delays. 5) Network attackers could manipulate MAC address and IP address mappings in ARP messages with the intent of intercepting network traffic.
Which statement describes the treatment of ARP requests on the local link?
1) They must be forwarded by all routers on the local network. 2) *They are received and processed by every device on the local network.* 3) They are dropped by all switches on the local network. 4) They are received and processed only by the target device.
What statement describes a characteristic of MAC addresses?
1) They must be globally unique.* 2) They are only routable within the private network. 3) They are added as part of a Layer 3 PDU. 4) They have a 32-bit binary value.
What is auto-MDIX?
1) a type of Cisco switch 2) an Ethernet connector type 3) a type of port on a Cisco switch 4) *a feature that detects Ethernet cable type*
Which switching method uses the CRC value in a frame?
1) cut-through 2) fast-forward 3) fragment-free 4) store-and-forward*
What addressing information is recorded by a switch to build its MAC address table?
1) the destination Layer 3 address of incoming packets 2) the destination Layer 2 address of outgoing frames 3) the source Layer 3 address of outgoing packets 4) *the source Layer 2 address of incoming frames*
What happens to runt frames received by a Cisco Ethernet switch?
1)The frame is dropped.* 2) The frame is returned to the originating network device. 3)The frame is broadcast to all other devices on the same network. 4)The frame is sent to the default gateway.
What is the decimal equivalent of the hexadecimal value of 3F?
63
Fill in the blank using a number. The minimum Ethernet frame size is _____________________________ bytes. Anything smaller than that should be considered a "runt frame."
64
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
What statement illustrates a drawback of the CSMA/CD access method?
Collisions can decrease network performance.*
What is a characteristic of a contention-based access method?
It is a nondeterministic method.*
Which action is taken by a Layer 2 switch when it receives a Layer 2 broadcast frame?
It sends the frame to all ports except the port on which it received the frame.
A host is trying to send a packet to a device on a remote LAN segment, but there are currently no mappings in its ARP cache. How will the device obtain a destination MAC address?
It will send an ARP request for the MAC address of the default gateway.*
ill in the blank. The Ethernet _______________________________ sublayer is responsible for communicating directly with the physical layer.
MAC
Which address or combination of addresses does a Layer 3 switch use to make forwarding decisions?
MAC and IP addresses*
Fill in the blank. On a Cisco switch, ________________ memory buffering is used to buffer frames in queues linked to specific incoming and outgoing ports.
PORT BASED
Fill in the blank. A collision fragment, also known as a ____________________ frame, is a frame of fewer than 64 bytes in length.
RUNT
Fill in the blank. ARP ______________________ is a technique that is used to send fake ARP messages to other hosts in the LAN. The aim is to associate IP addresses to the wrong MAC addresses.
SPOOFING
A network administrator issues the following commands on a Layer 3 switch: DLS1(config)# interface f0/3 DLS1(config-if)# no switchport DLS1(config-if)# ip address 172.16.0.1 255.255.255.0 DLS1(config-if)# no shutdown DLS1(config-if)# end What is the administrator configuring?
a routed port*
What type of address is 01-00-5E-0A-00-02?
an address that reaches a specific group of hosts
Fill in the blank. On Ethernet networks, the hexadecimal address FF-FF-FF-FF-FF-FF represents the _____________________________ MAC
broacast
How does adding an Ethernet line card affect the form factor of a switch?
by expanding the port density*
What is the purpose of the preamble in an Ethernet frame?
is used for timing synchronization*
Fill in the blank. On a Cisco switch, ___________________________ memory buffering is used to buffer frames in queues linked to specific incoming and outgoing ports.
port-based
What is the primary purpose of ARP?
resolve IPv4 addresses to MAC addresses
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?
shared memory buffering
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?
shared memory buffering*
When a switch configuration includes a user-defined error threshold on a per-port basis, to which switching method will the switch revert when the error threshold is reached?
store-and-forward
When would a switch record multiple entries for a single switch port in its MAC address table?
when another switch is connected to the switch port*
