Collisions can decrease network performance.
It is more complex than non-deterministic protocols.
CSMA/CD LAN technologies are only available at slower speeds than other LAN technologies.
Deterministic media access protocols slow network performance.
a routed port
a switched virtual interface
a trunk interface
a Cisco Express Forwarding instance
In an attempt to conserve bandwidth and not forward useless
frames, Ethernet devices drop frames that are considered to
be runt (less than 64 bytes) or jumbo (greater than 1500 bytes)
The frame is returned to the originating network device.
The frame is sent to the default gateway.
The frame is dropped.
The frame is broadcast to all other devices on the same network.
The minimum Ethernet frame is 64 bytes. The maximum
Ethernet frame is 1518 bytes. A network technician must know
the minimum and maximum frame size in order to recognize
runt and jumbo frames.
Ethernet is the most common LAN protocol in the world. It
operates at Layer 1 and 2, but is not required for Internet
communication. The OSI model is used to describe how
networks operate. A WAN connects multiple sites located in
It connects multiple sites such as routers located in different countries.
It defines a standard model used to describe how networking works.
It is the required Layer 1 and 2 standard for Internet communication.
It defines the most common LAN type in the world.
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).
Logical link control is implemented in software.
The LLC sublayer adds a header and a trailer to the data.
The LLC sublayer is responsible for the placement and retrieval of frames on and off the media.
The data link layer uses LLC to communicate with the upper layers of the protocol suite.
Logical link control is specified in the IEEE 802.3 standard.
Any vendor selling Ethernet devices must register with the
IEEE to ensure the vendor is assigned a unique 24-bit code,
which becomes the first 24 bits of the MAC address. The last
24 bits of the MAC address are generated per hardware
device. This helps to ensure globally unique addresses for
each Ethernet device.
They are only routable within the private network.
They have a 32-bit binary value.
They must be globally unique.
They are added as part of a Layer 3 PDU.
A MAC address is composed of 6 bytes. The first 3 bytes are
used for vendor identification and the last 3 bytes must be
assigned a unique value within the same OUI. MAC addresses
are implemented in hardware. A NIC needs a MAC address to
communicate over the LAN. The IEEE regulates the MAC
MAC addresses are implemented by software.
The ISO is responsible for MAC addresses regulations.
The first three bytes are used by the vendor assigned OUI.
A NIC only needs a MAC address if connected to a WAN.
The purpose of an ARP request is to find the MAC address of
the destination host on an Ethernet LAN. The ARP process
sends a Layer 2 broadcast to all devices on the Ethernet LAN.
The frame contains the IP address of the destination and the
broadcast MAC address, FFFF.FFFF.FFFF.
A switch builds a MAC address table by inspecting incoming
Layer 2 frames and recording the source MAC address found
in the frame header. The discovered and recorded MAC
address is then associated with the port used to receive the
the destination Layer 2 address of outgoing frames
the source Layer 3 address of outgoing packets
the source Layer 2 address of incoming frames
the destination Layer 3 address of incoming packets
The MAC address of PC3 is not present in the MAC table of
the switch. Because the switch does not know where to send
the frame that is addressed to PC3, it will forward the frame to
all the switch ports, except for port 4, which is the incoming
The switch will forward the frame to all ports.
The switch will forward the frame to all ports except port 4.
The switch will discard the frame.
The switch will forward the frame only to port 2.
The switch will forward the frame only to ports 1 and 3.
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
Auto-MDIX is a feature that is enabled on the latest Cisco
switches and that allows the switch to detect and use whatever
type of cable is attached to a specific port.
a type of Cisco switch
a feature that detects Ethernet cable type
a type of port on a Cisco switch
an Ethernet connector type
When a network device wants to communicate with another
device on the same network, it sends a broadcast ARP
request. In this case, the request will contain the IP address of
PC2. The destination device (PC2) sends an ARP reply with its
RT1 will send an ARP reply with the PC2 MAC address.
SW1 will send an ARP reply with the PC2 MAC address.
SW1 will send an ARP reply with its Fa0/1 MAC address.
PC2 will send an ARP reply with its MAC address.
RT1 will send an ARP reply with its Fa0/0 MAC address.
to associate IP addresses to the wrong MAC address
to flood the network with ARP reply broadcasts
to overwhelm network hosts with ARP requests
to fill switch MAC address tables with bogus addresses
選擇要在Apple App Store上查看的Topgrade應用程序。