2021 Apr 200-105 exams
Q11. - (Topic 1)
At which layer of the OSI model is RSTP used to prevent loops?
A. physical
B. data link
C. network
D. transport
Answer: B
Explanation: RSTP and STP operate on switches and are based on the exchange of Bridge Protocol Data Units (BPDUs) between switches. One of the most important fields in BPDUs is the Bridge Priority in which the MAC address is used to elect the Root Bridge , RSTP operates at Layer 2. http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cf a.shtml
Q12. - (Topic 2)
A router receives information about network 192.168.10.0/24 from multiple sources. What will the router consider the most reliable information about the path to that network?
A. an OSPF update for network 192.168.0.0/16
B. a static route to network 192.168.10.0/24
C. a static route to network 192.168.10.0/24 with a local serial interface configured as the next hop
D. a RIP update for network 192.168.10.0/24
E. a directly connected interface with an address of 192.168.10.254/24
F. a default route with a next hop address of 192.168.10.1
Answer: E
Explanation:
What Is Administrative Distance? http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094195.shtml
Select the Best Path Administrative distance is the first criterion that a router uses to determine which routing protocol to use if two protocols provide route information for the same destination. Administrative distance is a measure of the trustworthiness of the source of the routing information. Administrative distance has only local significance, and is not advertised in routing updates. Note: The smaller the administrative distance value, the more reliable the protocol. For example, if a router receives a route to a certain network from both Open Shortest Path First (OSPF) (default administrative distance - 110) and Interior Gateway Routing Protocol (IGRP) (default administrative distance - 100), the router chooses IGRP because IGRP is more reliable. This means the router adds the IGRP version of the route to the routing table.
Q13. - (Topic 2)
Refer to the exhibit.
What address is a feasible successor?
A. 172.16.4.0
B. 10.1.4.4
C. 10.1.2.2
D. 172.16.3.0
Answer: C Explanation:
The feasible condition states:
“To qualify as a feasible successor, a router must have an AD less than the FD of the current successor route”.
In this case, we see 10.1.2.2 shows an AD less than the current successor of 10.1.4.4
Q14. - (Topic 3)
Refer to the exhibit.
Which statement describes DLCI 17?
A. DLCI 17 describes the ISDN circuit between R2 and R3.
B. DLCI 17 describes a PVC on R2. It cannot be used on R3 or R1.
C. DLCI 17 is the Layer 2 address used by R2 to describe a PVC to R3.
D. DLCI 17 describes the dial-up circuit from R2 and R3 to the service provider.
Answer: C
Explanation:
DLCI stands for Data Link Connection Identifier. DLCI values are used on Frame Relay interfaces to distinguish between different virtual circuits. DLCIs have local significance because, the identifier references the point between the local router and the local Frame Relay switch to which the DLCI is connected.
Q15. - (Topic 2)
What can be done to secure the virtual terminal interfaces on a router? (Choose two.)
A. Administratively shut down the interface.
B. Physically secure the interface.
C. Create an access list and apply it to the virtual terminal interfaces with the access-group command.
D. Configure a virtual terminal password and login process.
E. Enter an access list and apply it to the virtual terminal interfaces using the access-class command.
Answer: D,E
Explanation:
It is a waste to administratively shut down the interface. Moreover, someone can still access the virtual terminal interfaces via other interfaces -> A is not correct.
We can not physically secure a virtual interface because it is “virtual” -> B is not correct.
To apply an access list to a virtual terminal interface we must use the “access-class” command. The “access-group” command is only used to apply an access list to a physical interface -> C is not correct; E is correct.
The most simple way to secure the virtual terminal interface is to configure a username & password to prevent unauthorized login -> D is correct.
Q16. - (Topic 2)
Which command is used to display the collection of OSPF link states?
A. show ip ospf link-state
B. show ip ospf lsa database
C. show ip ospf neighbors
D. show ip ospf database
Answer: D
Explanation:
http://www.cisco.com/en/US/docs/ios/iproute_ospf/command/reference/iro_osp3.html#wp1 01217 Examples The following is sample output from the show ip ospf database command when no arguments or keywords are used: Router# show ip ospf database OSPF Router with id(192.168.239.66) (Process ID 300)
Q17. - (Topic 2)
Which statements are true about EIGRP successor routes? (Choose two.)
A. A successor route is used by EIGRP to forward traffic to a destination.
B. Successor routes are saved in the topology table to be used if the primary route fails.
C. Successor routes are flagged as 'active' in the routing table.
D. A successor route may be backed up by a feasible successor route.
E. Successor routes are stored in the neighbor table following the discovery process.
Answer: A,D
Explanation:
Introduction to EIGRP http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f07.shtml
Feasible Successors A destination entry is moved from the topology table to the routing table when there is a feasible successor. All minimum cost paths to the destination form a set. From this set, the neighbors that have an advertised metric less than the current routing table metric are considered feasible successors.
Feasible successors are viewed by a router as neighbors that are downstream with respect to the destination.
These neighbors and the associated metrics are placed in the forwarding table.
When a neighbor changes the metric it has been advertising or a topology change occurs in the network, the set of feasible successors may have to be re-evaluated. However, this is not categorized as a route recomputation.
Q18. - (Topic 2)
Refer to the exhibit.
Host A pings interface S0/0 on router 3, what is the TTL value for that ping?
A. 253
B. 252
C. 255
D. 254
Answer: A
Explanation:
From the CCNA ICND2 Exam book: “Routers decrement the TTL by 1 every time they forward a packet; if a router decrements the TTL to 0, it throws away the packet. This prevents packets from rotating forever.” I want to make it clear that before the router forwards a packet, the TTL is still remain the same. For example in the topology above, pings to S0/1 and S0/0 of Router 2 have the same TTL.
The picture below shows TTL values for each interface of each router and for Host B.
Notice that Host A initializes ICMP packet with a TTL of 255:
Q19. - (Topic 2)
A network administrator is troubleshooting an EIGRP problem on a router and needs to confirm the IP addresses of the devices with which the router has established adjacency. The retransmit interval and the queue counts for the adjacent routers also need to be checked. What command will display the required information?
A. Router# show ip eigrp adjacency
B. Router# show ip eigrp topology
C. Router#show ip eigrp interfaces
D. Router#show ip eigrp neighbors
Answer: D
Explanation:
Implementing EIGRP http://www.ciscopress.com/articles/article.asp?p=1171169&seqNum=3Below is an example of the show ip eigrp neighbors command. The retransmit interval (Smooth Round Trip Timer – SRTT) and the queue counts (Q count, which shows the number of queued EIGRP packets) for the adjacent routers are listed: R1#show ip eigrp neighbors IP-EIGRP neighbors for process 1 H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num
0 10.10.10.2 Fa0/0 12 00:00:39 1282 5000 0 3
Q20. - (Topic 3)
The command show frame-relay map gives the following output:
Serial 0 (up): ip 192.168.151.4 dlci 122, dynamic, broadcast, status defined, active
Which statements represent what is shown?(Choose three.)
A. 192.168.151.4 represents the IP address of the remote router
B. 192.168.151.4 represents the IP address of the local serial interface
C. DLCI 122 represents the interface of the remote serial interface
D. DLCI 122 represents the local number used to connect to the remote address
E. broadcast indicates that a dynamic routing protocol such as RIP v1 can send packets across this PVC
F. active indicates that the ARP process is working
Answer: A,D,E
Explanation:
http://www.cisco.com/en/US/docs/ios/12_2/wan/command/reference/wrffr4.html#wp102934