You are a network administrator for your organization. Your organization has two Virtual LANs, named Marketing and Production. All switches in the network have
both VLANs configured on them. Switches A, C, F, and G have user machines connected for both VLANs, whereas switches B, D, and E have user machines
connected to the Production VLAN only. (Click the Exhibit(s) button to view the network diagram.)
To meet a new requirement, Marketing VLAN users must communicate with Production VLAN users and vice versa. What changes would be required for the
network in this scenario?
A.
Disable VTP pruning.
B.
Convert all switch ports into trunk ports.
C.
Create an access list with permit statements.
D.
Install a routing device or enable Layer 3 routing on a switch.
Explanation:
In this scenario, either a Layer 3 device or Layer 3 routing on a switch would be required to implement inter-VLAN routing. Although you could use multiple physical
interfaces for the VLAN traffic, using trunk links between the switches and an external router would make more efficient use of the physical interfaces that you have.
Only trunk links can carry traffic from multiple VLANs. These data frames must be frame tagged over the trunk link to identify the VLAN that sourced the frame. The
receiving switch sees the VLAN ID, and uses this information to forward the frame appropriately. Additionally, the cables used to connect the router to the switches
must be a straight-through cable and not a crossover cable.
When trunks links do not appear to be operating, it is always a good idea to make sure the port used for the trunk link is set as a trunk link and not as an access
link. For example, the output below of the show interface fastethernet 0/15 switchport command indicates that Switch2 will not trunk because the port is set as an
access link. This is shown in line 5 of the output:
<<output omitted>>
Switch2#show Interface fastethernet 0/15 switchport
Name: Fa0/15
SwitchportEnabled
Administrative Mode: access
Operational Mode: access
<<output omitted>>
The VLAN Trunking Protocol (VTP) pruning feature restricts unnecessary broadcast traffic between multiple switches. It does not affect inter-VLAN traffic.
Therefore, disabling VTP pruning will not permit inter-VLAN communication between the Marketing and Production VLANs.
Converting all switch ports into trunk ports will permit traffic from multiple VLANs to traverse over these links. However, traffic from one VLAN will be restricted to
that VLAN only, and inter-VLAN communication will not be possible.
Access lists can permit or deny packets based on the packets’ source/destination IP address, protocol, or port number. However, access lists can manipulate interVLAN traffic only when inter-VLAN traffic is enabled using a Layer 3 device or Layer 3 routing. Therefore, creating access lists will not enable inter-VLAN routing
between the Marketing and Production VLANs.
Objective:
Network Fundamentals
Sub-Objective:
Describe the impact of infrastructure components in an enterprise network