Refer to the exhibit.

What two results would occur if the hub were to be replaced with a switch that is configured
with one Ethernet VLAN? (Choose two.)

A.
The number of collision domains would remain the same.

B.
The number of collision domains would decrease.

C.
The number of collision domains would increase.

D.
The number of broadcast domains would remain the same.

E.
The number of broadcast domains would decrease.

F.
The number of broadcast domains would increase.

Explanation:
Basically, a collision domain is a network segment that allows normal network traffic to flow
back and forth. In the old days of hubs, this meant you had a lot of collisions, and the old
CSMA/CD would be working overtime to try to get those packets re-sent every time there
was a collision on the wire (since ethernet allows only one host to be transmitting at once
without there being a traffic jam). With switches, you break up collision domains by switching
packets bound for other collision domains. These days, since we mostly use switches to
connect computers to the network, you generally have one collision domain to a PC.
Broadcast domains are exactly what they imply: they are network segments that allow
broadcasts to be sent across them. Since switches and bridges allow for broadcast traffic to
go unswitched, broadcasts can traverse collision domains freely. Routers, however, don’t
allow broadcasts through by default, so when a broadcast hits a router (or the perimeter of a
VLAN), it doesn’t get forwarded. The simple way to look at it is this way: switches break up
collision domains, while routers (and VLANs) break up collision domains and broadcast
domains. Also, a broadcast domain can contain multiple collision domains, but a collision
domain can never have more than one broadcast domain associated with it.
Collision Domain: A group of Ethernet or Fast Ethernet devices in a CSMA/CD LAN that are
connected by repeaters and compete for access on the network. Only one device in the
collision domain may transmit at any one time, and the other devices in the domain listen to
the network in order to avoid data collisions. A collision domain is sometimes referred to as
an Ethernet segment.
Broadcast Domain: Broadcasting sends a message to everyone on the local network
(subnet). An example for Broadcasting would be DHCP Request from a Client PC. The
Client is asking for a IP Address, but the client does not know how to reach the DHCP
Server. So the client sends a DHCP Discover packet to EVERY PC in the local subnet
(Broadcast). But only the DHCP Server will answer to the Request.
How to count them?
Broadcast Domain:
No matter how many hosts or devices are connected together, if they are connected with a
repeater, hub, switch or bridge, all these devices are in ONE Broadcast domain (assuming a
single VLAN). A Router is used to separate Broadcast-Domains (we could also call them
Subnets – or call them VLANs).
So, if a router stands between all these devices, we have TWO broadcast domains.
Collision Domain:
Each connection from a single PC to a Layer 2 switch is ONE Collision domain. For
example, if 5 PCs are connected with separate cables to a switch, we have 5 Collision
domains. If this switch is connected to another switch or a router, we have one collision
domain more.
If 5 Devices are connected to a Hub, this is ONE Collision Domain. Each device that is
connected to a Layer 1 device (repeater, hub) will reside in ONE single collision domain.