Switch Sim

Refer to the topology

A customer network engineer has made configuration changes that have resulted in some loss of connectivity. You have been called in to evaluate a switch network and suggest resolutions to the problems.

Question 1

PC2 in VLAN 200 is unable to ping the gateway address 172.16.200.1; identify the issue.

A. VTP domain name mismatch on SW4
B. VLAN 200 not configured on SW1
C. VLAN 200 not configured on SW2
D. VLAN 200 not configured on SW4

Answer: D

Explanation

Check the interface E0/0 of SW4 via the “show running-config” command:

E0/0 is in access mode but no VLAN is associated with this interface so it belongs to VLAN 1 by default. Note: You can double check with the “show vlan” command to see no vlan 200 was created on SW4.

Question 2

Which of statement is true regarding STP issue identified with switches in the given topology?

A. Loopguard configured on the New_Switch places the ports in loop inconsistent state
B. Rootguard configured on SW1 places the ports in root inconsistent state
C. Bpduguard configured on the New_Switch places the access ports in error-disable
D. Rootguard configured on SW2 places the ports in root inconsistent state

Answer: A (?)

Explanation

We don’t have enough information to answer this question.. But under interface Ethernet2/1 of the New_Switch we see Loopguard is configured so answer A is correct. But it may not a STP issue if Ethernet2/1 is blocked because Loopguard should be placed on blocked/alternative ports to prevent unidirectional links.

Question 3

You have configured PVST+ load balancing between SW1 and the New_Switch in such a way that both the links E2/2 and E2/3 are utilized for traffic flow, which component of the configuration is preventing PVST+ load balancing between SW1 and SW2 links?

A. Port priority configuration on SW1
B. Port priority configuration on the New_Switch
C. Path cost configuration on SW1
D. Path cost configuration on the New_Switch

Answer: D

Explanation

Check interfaces E1/2 & E1/3 of New_Switch which are directly connected to SW1 with the “show running-config” command:

We can see the STP cost of E1/3 was configured to 250 so traffic will not go through this interface but E1/2 is still using the default value (STP cost of 100 for Ethernet port). If we use the default settings then traffic will go directly from SW1 to the New_Switch via E1/2. To force traffic to go through the links E2/2 and E2/3 of SW1 we can increase the cost of E1/2 (should be greater than 200 because by default the STP cost from SW1 -> SW2 -> New_Switch is 200).

Question 4

SW1 Switch Management IP address is not pingable from SW4. What could be the issue?

A. Management VLAN not allowed in the trunk links between SW1 and SW4
B. Management VLAN not allowed in the trunk links between SW1 and SW2
C. Management VLAN not allowed in the trunk link between SW2 and SW4
D. Management VLAN ip address on SW4 is configured in wrong subnet
E. Management VLAN interface is shutdown on SW4

Answer: D

Explanation

From the output of the “show vlan” (or “show running-config”) command on SW1, we learn VLAN 300 is named “Management_VLAN” so we need to check the connection of VLAN 300 between SW1 and SW4.

Issue the “show running-config” on SW1 & SW4 to check the IP addresses of their Interface VLAN:

We can see that the IP addresses of these two interfaces are not in the same subnets (192.168.10.1/24 & 192.168.100.4/24). We can double check the IP address of interface VLAN 30 on Sw2 to see it belongs to 192.168.10.0/24 subnet.