200-125 | Up to date 200-125 Exam Study Guides With New Update Exam Questions

Q1. Given an IP address 172.16.28.252 with a subnet mask of 255.255.240.0, what is the correct network address?

A. 172.16.16.0

B. 172.16.0.0

C. 172.16.24.0

D. 172.16.28.0

Answer: A

Explanation:

For this example, the network range is 172.16.16.1 - 172.16.31.254, the network address is 172.16.16.0 and the broadcast IP address is 172.16.31.255.

Q2. Refer to the exhibit.

Which two statements are true about interVLAN routing in the topology that is shown in the exhibit? (Choose two.)

A. Host E and host F use the same IP gateway address.

B. Router1 and Switch2 should be connected via a crossover cable.

C. Router1 will not play a role in communications between host A and host D.

D. The FastEthernet 0/0 interface on Router1 must be configured with subinterfaces.

E. Router1 needs more LAN interfaces to accommodate the VLANs that are shown in the exhibit.

F. The FastEthernet 0/0 interface on Router1 and the FastEthernet 0/1 interface on Switch2 trunk ports must be configured using the same encapsulation type.

Answer: D,F

Explanation:

In order for multiple VLANs to connect to a single physical interface on a Cisco router, subinterfaces must be used, one for each VLAN. This is known as the router on a stick configuration. Also, for any trunk to be formed, both ends of the trunk must agree on the encapsulation type, so each one must be configured for 802.1q or ISL.

Q3. Which switch would STP choose to become the root bridge in the selection process?

A. 32768: 11-22-33-44-55-66

B. 32768: 22-33-44-55-66-77

C. 32769: 11-22-33-44-55-65

D. 32769: 22-33-44-55-66-78

Answer: A

Explanation:

The root bridge of the spanning tree is the bridge with the smallest (lowest) bridge ID. Each bridge has a configurable priority number and a MAC Address; the bridge ID contains both numbers combined together - Bridge priority + MAC (32768.0200.0000.1111). The Bridge priority default is 32768 and can only be configured in multiples of 4096(Spanning tree uses the 12 bits extended system ID). To compare two bridge IDs, the priority is compared first, as if looking at a real number anything less than 32768...will become the target of being the root. If two bridges have equal priority then the MAC addresses are compared; for example, if switches A (MAC=0200.0000.1111) and B (MAC=0200.0000.2222) both have a priority of 32768 then switch A will be selected as the root bridge.

In this case, 32768: 11-22-33-44-55-66 would be the bridge because it has a lower priority and MAC address.

Q4. Which statements describe the routing protocol OSPF? (Choose three.)

A. It supports VLSM.

B. It is used to route between autonomous systems.

C. It confines network instability to one area of the network.

D. It increases routing overhead on the network.

E. It allows extensive control of routing updates.

F. It is simpler to configure than RIP v2.

Answer: A,C,E

Explanation:

The OSPF protocol is based on link-state technology, which is a departure from the Bellman-Ford vector based algorithms used in traditional Internet routing protocols such as RIP. OSPF has introduced new concepts such as authentication of routing updates, Variable Length Subnet Masks (VLSM), route summarization, and so forth.

OSPF uses flooding to exchange link-state updates between routers. Any change in routing information is flooded to all routers in the network. Areas are introduced to put a boundary on the explosion of link-state updates. Flooding and calculation of the Dijkstra algorithm on a router is limited to changes within an area.

Q5. Refer to the exhibit.

Given this output for SwitchC, what should the network administrator's next action be?

A. Check the trunk encapsulation mode for SwitchC's fa0/1 port.

B. Check the duplex mode for SwitchC's fa0/1 port.

C. Check the duplex mode for SwitchA's fa0/2 port.

D. Check the trunk encapsulation mode for SwitchA's fa0/2 port.

Answer: C

Explanation:

Here we can see that this port is configured for full duplex, so the next step would be to check the duplex setting of the port on the other switch. A mismatched trunk encapsulation would not result in input errors and CRC errors.

Q6. Which two protocols are used by bridges and/or switches to prevent loops in a layer 2 network? (Choose two.)

A. 802.1d

B. VTP

C. 802.1q

D. STP

E. SAP

Answer: A,D

Explanation:

This question is to examine the STP protocol. STP (802.1d) is used to prevent Layer 2 loops.

802.1q is a Frame Relay protocol which belongs to VLAN. SAP is a concept of the OSI model.

Q7. Users have been complaining that their Frame Relay connection to the corporate site is very slow. The network administrator suspects that the link is overloaded.

Based on the partial output of the Router# show frame relay pvc command shown in the graphic, which output value indicates to the local router that traffic sent to the corporate site is experiencing congestion?

A. DLCI = 100

B. last time PVC status changed 00:25:40

C. in BECN packets 192

D. in FECN packets 147

E. in DE packets 0

Answer: C

Explanation:

If device A is sending data to device B across a Frame Relay infrastructure and one of the intermediate Frame Relay switches encounters congestion, congestion being full buffers, over-subscribed port, overloaded resources, etc, it will set the BECN bit on packets being returned to the sending device and the FECN bit on the packets being sent to the receiving device.

Q8. Which statement describes VRRP object tracking?

A. It monitors traffic flow and link utilization.

B. It ensures the best VRRP router is the virtual router master for the group.

C. It causes traffic to dynamically move to higher bandwidth links.

D. It thwarts man-in-the-middle attacks.

Answer: B

Explanation:

Object tracking is the process of tracking the state of a configured object and uses that state to determine the priority of the VRRP router in a VRRP group.

Q9. Which command reveals the last method used to powercycle a router?

A. show reload

B. show boot

C. show running-config

D. show version

Answer: D

Explanation:

The u201cshow versionu201d command can be used to show the last method to powercycle (reset) a router.

Q10. Refer to the exhibit.

At the end of an RSTP election process, which access layer switch port will assume the discarding role?

A. Switch3, port fa0/1

B. Switch3, port fa0/12

C. Switch4, port fa0/11

D. Switch4, port fa0/2

E. Switch3, port Gi0/1

F. Switch3, port Gi0/2

Answer: C

Explanation:

In this question, we only care about the Access Layer switches (Switch3 & 4). Switch 3 has a lower bridge ID than Switch 4 (because the MAC of Switch3 is smaller than that of Switch4) so both ports of Switch3 will be in forwarding state. The alternative port will surely belong to Switch4.

Switch4 will need to block one of its ports to avoid a bridging loop between the two switches. But how does Switch4 select its blocked port? Well, the answer is based on the BPDUs it receives from Switch3. A BPDU is superior to another if it has:

1. A lower Root Bridge ID

2. A lower path cost to the Root

3. A lower Sending Bridge ID

4. A lower Sending Port ID

These four parameters are examined in order. In this specific case, all the BPDUs sent by Switch3 have the same Root Bridge ID, the same path cost to the Root and the same Sending Bridge ID. The only parameter left to select the best one is the Sending Port ID (Port ID = port priority + port index). In this case the port priorities are equal because they use the default value, so Switch4 will compare port index values, which are unique to each port on the switch, and because Fa0/12 is inferior to Fa0/1, Switch4 will select the port connected with Fa0/1 (of Switch3) as its root port and block the other port -> Port fa0/11 of Switch4 will be blocked (discarding role).