Chapter 7: Ethernet Lan Switching Concepts

Front 1

Ethernet bridges give what two benefits

Back 1

Reduce the number of collisions in the network

Add bandwidth to the network

Front 2

definition of microsegmenetation

Back 2

the effect when a switch segments an Ethernet LAN into one collision domain per interface

Front 3

Unicast address

Back 3

MAC address that identifies a single LAN interface card

Front 4

Broadcast address

Back 4

All devices on the LAN should receive and process the frame
(or, all devices in the same broadcast domain, right?)

Front 5

Multicast address

Back 5

used to allow a dynamic subset of devices on a LAN to communicate

Front 6

STP

Back 6

Spanning Tree Protocol

Front 7

Purpose of STP

Back 7

prevent switches from sending frames in an endless loop

Front 8

Other names for the switch's MAC address table

Back 8

switching table
bridging table
Content Addressable Memory

Front 9

CAM stands for / refers to?

Back 9

Content Addressable Memory

refers to the type of physical memory switches use to store the MAC address table

Front 10

Difference between forwarding / filtering

Back 10

forwarding = frame is sent out one or all ports

filtering = frame is discarded

Front 11

The MAC address table consists of what columns

Back 11

MAC addresses, corresponding outgoing interfaces, time since that address last sent data through the switch

Front 12

definition of "unknown unicast frame"

Back 12

frames whose destination MAC addresses are not yet in the bridging table

Front 13

Definition of "flooding"

Back 13

Sending a frame out all interfaces except the one it came in on

Front 14

Which types of frames are flooded by switches

Back 14

unknown unicast frames, broadcast frames, multicast frames (unless the switch has been configured to use some multicast optimization tools)

Front 15

T/F: STP behaves identically for a transparent bridge and a switch

Back 15

True

Front 16

STP causes each interface on a switch to settle into either a _______ state or a ______ state

Back 16

blocking, forwarding

Front 17

Almost all of the more recently released switches use ________ processing

Back 17

store-and-forward

Front 18

What are the three types of internal processing methods in Cisco switches?

Back 18

store-and-forward
cut-through
fragment-free

Front 19

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?

Back 19

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

Front 20

What is the advantage of store-and-forward processing?

Back 20

It allows the switch to check the FCS at the end of the frame before forwarding it.

Front 21

Definition of "rate adaptation"

Back 21

Devices of different speeds can both communicate to the same switch

Front 22

T/F: Hubs can support rate adaptation

Back 22

False

Front 23

What does a switch do when it receives a frame from a MAC address which is already in the address table

Back 23

Its timer is reset to zero.

Front 24

Only ______ stop the flow of broadcasts

Back 24

Routers (except when VLANs are used??)

Front 25

What does the term "broadcast firewall" refer to?

Back 25

The fact that routers do not forward LAN broadcasts

Front 26

A LAN consists of all devices in the same _________

Back 26

broadcast domain

Front 27

Cisco switches put all interfaces in which VLAN by default?

Back 27

VLAN 1

Front 28

What does the term "campus LAN" refer to?

Back 28

A LAN created to support larger buildings, or multiple buildings in somewhat close proximity to one another

Front 29

What are the three terms to describe the different roles a switch can take in a campus LAN?

Back 29

access, distribution, core

Front 30

access switches (should / should not) be expected to forward traffic between two other switches

Back 30

should not

Front 31

purpose of access switches?

Back 31

send traffic to and from the end-user devices to which they are connected

Front 32

purpose of distribution switches?

Back 32

provide a path through which the access switches can forward traffic to each other

Front 33

Each access switch connects to how many distribution switches?

Back 33

at least one, usually 2 for redundancy

Front 34

T/F: Small to medium campus LANs often forego the concept of core switches

Back 34

True

Front 35

What are the two methods of generating light in fiber-optic cables?

Back 35

Laser and LED

Front 36

Which type of fiber-optic cable is cheaper and supports shorter distances? (single-mode / multimode)

Back 36

multimode

Front 37

Which type of fiber-optic cable is more expensive and supports longer distances? (single-mode / multimode)

Back 37

single-mode

Front 38

LEDs are most often used with (single-mode / multimode) fiber optic cable

Back 38

multimode

Front 39

Lasers are most often used with (single-mode / multimode) fiber optic cable

Back 39

single-mode