Configuring VLANs

VLANs again:

Hosts in different VLANs can't communicate. To make it possible for hosts on two switches but in the same VLAN you have to configure a trunk port. But to configure this VLAN you first have to set them up. A VLAN needs a configured number (e.g. VLAN 20) and a name (e.g. Faculty).

It is important to tell the interfaces that they are now the ports for a VLAN.

To make a port a trunk port you have to change it's switchport mode to trunk.
 

One Lesson three exercises concerning VLAN

VLANs:

VLANs (Virtual Local Area Network) split a network into logical parts. This makes the networkadministration much easier. The splitting of the network takes part on switches, therefor on Layer 2. With using VLANs the network is splitted into many broadcast domains. If a host in a VLAN sends a broadcast the hosts of the other VLAN can not "hear" that broadcast. This needs less bandwith than sending the broadcast out to all the hosts and boosts the performance of the network.

Exercise 3.1.1.5 Who hears the broadcast?: 

In this exercise we had to test if the hosts are connected. (They were) Afterwards we had to test a broadcast in the simulation mode. You can see how the host, that sends the broadcast, sends it's broadcast packet to the switch. The switch duplicates it and sends it to the hosts, that are in the same VLAN as the first host.

1.     If a PC in VLAN 10 sends a broadcast message, which devices receive it?

 PC8 to PC15

2.     If a PC in VLAN 20 sends a broadcast message devices receive it?

 PC16 to PC23

3.     If a PC in VLAN 30 sends a broadcast message devices receive it?

 PC0 to PC7

4.     What happens to a frame sent from a PC in VLAN 10 to a PC in VLAN 30?

 It gets lost

5.     Which ports on the switch light up if a PC connected to port 11 sends a unicast message to a PC connected to port 13?

 Port 11 and Port 13

6.     Which ports on the switch light if a PC connected to port 2 sends a unicast message to a PC connected to port 23?

 Port 2

7.     In terms of ports, what are the collision domains on the switch?

 The area where frames can collide.

8.     In terms of ports, what are the broadcast domains on the switch?

 The area where you are able to recive a broadcast - VLANs.

3.1.2.7 Investigating a VLAN Implementatiton:

 

If hosts are in the same VLAN they are able to communicate even though they are in different subnets. If hosts are in different subnets, they are not able to communicate. To see that, we had to ping hosts in the same and hosts in different networks.