Cisco Chapter Five
what is the layer 2 multicast address MAC address that corresponds to the Layer 3 IPv4 multicast address 224.139.34.56
01-00-5E-0B-22-38
binary number 0000 1010
0A hexadecimal
Address Resolution Protocol
ARP
Destination Address
Assists a host in determining if the frame received is addressed to it
LLC
Controls the network interface card through software drivers
Type
Describes which higher-level protocol has been used
Which two statements are correct about MAC and IP addresses during data transmission if NAT is not involved
Destination and source MAC addresses have local significance and change every time a frame goes from one LAN to another Destination IP addresses in a packet header remain constant along the entire path to a target host
Frame Check Sequence
Detects errors in an Ethernet frame
FCS
Frame Check Sequence
what address or combination of addresses does a Layer 3 switch use to make forwarding decisions?
MAC and IP addresses
Preamble
Notifies destinations to get ready for a new frame
PC1 issues an ARP request because it needs to send a packet to PC2. In this scenario, what will happen next?
PC2 will send an ARP request with its MAC address
SFD
Start Frame Delimiter
Start of Frame Delimiter
Synchronizes sending and receiving devices for frame delivery
Source Address
The frame's originating NIC or interface MAC address
802.2 Header and Data
Uses Pad to increase this frame field to at least 64 bytes
LLC
Works with the upper layers to add application information for delivery of data to higher level protocols
Which two statements describe a fixed configuration ethernet switch
a fixed configuration switch may be stackable the number of ports on the switch cannot be increased
store-and-forward
always stores the entire frame checks the CRC before forwarding checks the frame length before forwarding
full-duplex
bidirectional data flow where data can be sent and received at the same time. reduces the wait time between transmissions
how does adding an ethernet line card affect the form factor of a switch
by expanding the port density
what statement illustrates a drawback of the CSMA/CD access method?
collisions can decrease network performance
MAC
controls access to the media through signaling and physical media standards requirements
CRC
cyclic redundancy check
cut-through switching
forwards the frame before it is entirely received
cut-through forwarding
has low latency may forward runt frames begins forwarding when the destination address is received
What are two features of ARP?
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 If a device receiving an ARP request has the destination IPv4 address, it responds with an ARP reply
what is the purpose of the preamble in an ethernet frame
is used for timing synchronization
what is a characteristic of a contention-based access method
it is a nondeterministic method
which two statements describe features or functions of the logical link control sublayer in Ethernet standards
logical link control is implemented in software the data link layer uses LLC to communicate with the upper layers of the protocol suite
What are two potential netowrk problems that can result from ARP operation?
on large networks with low bandwidth, multiple ARP broadcasts could cause data communication delays Network attackers could manipulate MAC address and IP address mappings in ARP messages with the intent of intercepting network traffic
store-and-forward switching
receives the entire frame and computers the CRC before forwarding
LLC
remains relatively independent of physical equipment
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
MAC
supports Ethernet technology by using CSMA/CD or CSMA/CA
which statement is true about MAC addresses
the first three bytes are used by the vendor assigned OUI
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?
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 features will configure the interfaces eliminating the need for a crossover cable
half-duplex
unidirectional data flow where sending and receiving data are not performed at the same time (walkie-talkie)
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
MAC
works with hardware to support bandwidth requirements-checks for errors in bits sent and received
