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Quiz!
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Ethernet bridges give what two benefits |
Reduce the number of collisions in the network Add bandwidth to the network |
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definition of microsegmenetation |
the effect when a switch segments an Ethernet LAN into one collision domain per interface |
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Unicast address |
MAC address that identifies a single LAN interface card |
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Broadcast address |
All devices on the LAN should receive and process the frame |
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Multicast address |
used to allow a dynamic subset of devices on a LAN to communicate |
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STP |
Spanning Tree Protocol |
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Purpose of STP |
prevent switches from sending frames in an endless loop |
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Other names for the switch's MAC address table |
switching table |
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CAM stands for / refers to? |
Content Addressable Memory refers to the type of physical memory switches use to store the MAC address table |
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Difference between forwarding / filtering |
forwarding = frame is sent out one or all ports filtering = frame is discarded |
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The MAC address table consists of what columns |
MAC addresses, corresponding outgoing interfaces, time since that address last sent data through the switch |
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definition of "unknown unicast frame" |
frames whose destination MAC addresses are not yet in the bridging table |
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Definition of "flooding" |
Sending a frame out all interfaces except the one it came in on |
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Which types of frames are flooded by switches |
unknown unicast frames, broadcast frames, multicast frames (unless the switch has been configured to use some multicast optimization tools) |
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T/F: STP behaves identically for a transparent bridge and a switch |
True |
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STP causes each interface on a switch to settle into either a _______ state or a ______ state |
blocking, forwarding |
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Almost all of the more recently released switches use ________ processing |
store-and-forward |
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What are the three types of internal processing methods in Cisco switches? |
store-and-forward |
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With which type of internal switch processing does the switch forward the frame only after receiving the first 64 bytes and why does it do this? |
fragment-free 64 bytes is enough for CSMA/CD to detect if a collision has occured. this allows the switch to avoid forwarding garbage from collided frames |
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What is the advantage of store-and-forward processing? |
It allows the switch to check the FCS at the end of the frame before forwarding it. |
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Definition of "rate adaptation" |
Devices of different speeds can both communicate to the same switch |
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T/F: Hubs can support rate adaptation |
False |
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What does a switch do when it receives a frame from a MAC address which is already in the address table |
Its timer is reset to zero. |
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Only ______ stop the flow of broadcasts |
Routers (except when VLANs are used??) |
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What does the term "broadcast firewall" refer to? |
The fact that routers do not forward LAN broadcasts |
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A LAN consists of all devices in the same _________ |
broadcast domain |
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Cisco switches put all interfaces in which VLAN by default? |
VLAN 1 |
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What does the term "campus LAN" refer to? |
A LAN created to support larger buildings, or multiple buildings in somewhat close proximity to one another |
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What are the three terms to describe the different roles a switch can take in a campus LAN? |
access, distribution, core |
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access switches (should / should not) be expected to forward traffic between two other switches |
should not |
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purpose of access switches? |
send traffic to and from the end-user devices to which they are connected |
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purpose of distribution switches? |
provide a path through which the access switches can forward traffic to each other |
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Each access switch connects to how many distribution switches? |
at least one, usually 2 for redundancy |
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T/F: Small to medium campus LANs often forego the concept of core switches |
True |
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What are the two methods of generating light in fiber-optic cables? |
Laser and LED |
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Which type of fiber-optic cable is cheaper and supports shorter distances? (single-mode / multimode) |
multimode |
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Which type of fiber-optic cable is more expensive and supports longer distances? (single-mode / multimode) |
single-mode |
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LEDs are most often used with (single-mode / multimode) fiber optic cable |
multimode |
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Lasers are most often used with (single-mode / multimode) fiber optic cable |
single-mode |
