Ch. 6 Building Ethernet LANs With Switches Flashcards
______ separated devices into groups called collision domains, reduced the number of collisions that occurred in the network because the frames inside one collision domain did not collide with frames in another collision domain, increased bandwidth by giving each collision domain its own separate bandwidth with one sender at a time per collision domain
Bridges
Ethernet switches receive ethernet frames in one port and then Forward or _____ the frames out one or more other ports
Switch
Bridges separated devices into groups called ______ ________
Collision domains
CD
Collision domain
Bridges created ______ separate 10-baseT networks
2
_____ switches received ethernet frames and then make a switching decision either for the frame out some other port or ignore the frame
LAN
_____ Perform three actions: deciding when to forward a frame or when to filter the frame based on the destination Mac address, learning Mac addresses by examining the source Mac address of each frame received by the switch, creating a layer 2 loop free environment with other bridges By using spanning tree protocol
Bridges
STP
Spanning tree protocol
To decide whether to forward a frame a _____ uses a dynamically built a table that lists Mac addresses and outgoing interface
Switch
A Mac address table is also called a
Switching table
The second main function of a _____ is to learn the Mac addresses and interfaces to put in its address table
Switch
Switches build the address table by listening to incoming frames and examining the source _____ address
MAC
If a _____ enters the switch and the source Mac address is not on the Mac address table the switch creates an entry in the table
Frame
Switches keep a time of each entry in the Mac address table called _____ _____
Inactivity timer
when there is no matching entry in the table switches forward the frame out all interfaces using a process called ______
Flooding
The third primary feature of LAN switches is loop prevention as implemented by_____
STP (spanning tree protocol)
Without _____ any flooded frames would loop indefinite period of time
STP
To avoid layer 2 loops all switches need to use STP which causes each interface almost wish to settle into either a _______ or _______ state
Blocking or forwarding
When the interface cannot forward or receive data frames it is
Blocking
When the interface can send and receive data frames it is
Forwarding
____ _____ ______ _____ requires the switch to receive the entire frame before forwarding the first bit of the front
Store and forward processing
____ _____ and ______ ______ processing methods allow the switch to start forwarding the frame before the entire frame has been received
Cut through and fragment free
With ____ _____ processing the switch start sending the frame out the output port as soon as possible
Cut through
Cut through does not allow time for the ____
FCS (frame check sequence)
_____ ______ processing works similar to cut through but it tries to reduce the number of error frames that it forwards
Fragment free
_____ ______ processing works like Cut through processing but it waits to receive the first 64 bytes before forwarding the frame
Fragment free
Today switches primary use the _____ ____ ______ processing method
Store and forward
____ switches provide the following benefits: switch ports connected to a single device microsegment the LAN providing dedicated bandwidth to that single device and switches allow multiple simultaneous conversations between devices on different ports
LAN
____ _____ means that devices that use different ethernet speeds can communicate through the switch (hubs cannot)
Rate adaptation
VLAN
Virtual local area network
The term ____ _____ referred to an ethernet concept of all ports whose transmitted frames would cause a collision with frames sent by other devices in the collision domain
Collision domain
An Ethernet _____ _____ is the set of devices to which the broadcast is delivered when sent from a single device
Broadcast domain
Only _____ separate the lan into multiple broadcast domains
Routers
A ______ ______ is a set of network interface cards for which a frame sent by one NIC could result in a collision with a frame sent by any other NIC in the same collision domain
Collision domain
A ______ _____ is a set of NICs for which a broadcast frame sent by one NICs is received by all other NICs in the same broadcast domain
Broadcast domain
A _____ consists of all devices in the same broadcast domain
LAN
A _____ uses switch group interfaces to create different broadcast domains based on configuration
VLAN
You can create multiple broadcast domains using a single_____
Switch
The term _____ LAN refers to the LAN created to support larger buildings or multiple building somewhere in close proximity to one another
Campus
Cisco uses three terms to describe the role of each switch and the campus design ____ _____ and _____
Access, distribution, and core
_____ switches connect directly to end-users providing user device access to the LAN
Access
In larger campus LANs _______ switches provide a path through which the access switches can for traffic to each other
Distribution
_____ aggregates distributions switches in a very large campus LANs providing for very high forwarding rates
Core
The three most common types of ethernet today are:
10base-t
100base-t
1000base-t
_______ Defines the protocol that lets two UTP-based ethernet nodes on the link to negotiate so that they can choose to use the same speed and duplex settings
Autonegotiation
Cisco devices using autonegotiation rely on two pieces of logic to determine network standards
Speed and duplex
Sense the speed, if that’s fails use IEEE default which is the slowest supported speed (often 10 MB per second)
Speed
Use the IEEE defaults. If the speed equals 10 or 100 use half duplex otherwise use full-duplex
Duplex
LAN ____ impact how autonegotiation works, resulting in the IEEE default setting 10 Mbps and half duplex
Hubs
How does a switch decide to forward a frame destined for a known unicast MAC address
It compares the unicast source address to the bridging or Mac address table
A LAN switch decides to forward a frame destined for a broadcast MAC address by
Forwarding the frame out all interfaces in the same VLAN except for the incoming interface
A switch with the frame Destined for an unknown unicast address
Forwards out all interfaces in the same VLAN except for the incoming interface
What comparison does a switch make when deciding whether a new Mac address should be added to its Mac address table
It compares the unicast source address to the bridging or Mac address table
Which of the following devices would be in the same collision domain as PC1
PC2 separated from PC1 by an ethernet hub
PC3 which is separated from PC1 by a transparent bridge
PC4 separated from PC1 by an ethernet switch
PC5 which is separated from PC1 buy a router
PC2 which is separate from PC1 by an ethernet hub
Which of the following devices would be in the same broadcast Domain as PC1 (choose three)
PC2 which is separated from PC1 by an Ethernet hub
PC3 which is separated from PC1 by a transparent bridge
PC4 which is separated from PC1 by an ethernet switch
PC5 which is separated from PC1 Bya router
PC 2
PC 3
PC 4
Which of the following ethernet standard supports maximum cable length of longer than 100 m (choose two answers) 100base-t 1000base-lx 1000base-t 1000base-fx
1000base-lx
1000base-fx
A Cisco LAN switch connects three PCs (PC1 PC2 and PC3) Each directly using a cable that supports ethernet UTP speeds up through 1000 Mbps (1gps). PC1 uses a NIC that supports only 10base-t, while PC2 has a 10/100 NIC, and PC3 has a 10/100/1000 NIC. Assuming that the PCs and switch use IEEE autonegotiation which PCs will use half duplex
None of the PCs will use half duplex
