100-105 Exam - Cisco Interconnecting Cisco Networking Devices Part 1 (ICND1 v3.0)

certleader.com

Q1. - (Topic 7) 

When enabled, which feature prevents routing protocols from sending hello messages on an interface'? 

A. virtual links 

B. passive-interface 

C. directed neighbors 

D. OSPF areas 

Answer:

Explanation: You can use the passive-interface command in order to control the advertisement of routing information. The command enables the suppression of routing updates over some interfaces while it allows updates to be exchanged normally over other interfaces. With most routing protocols, the passive-interface command restricts outgoing advertisements only. But, when used with Enhanced Interior Gateway Routing Protocol (EIGRP), the effect is slightly different. This document demonstrates that use of the passive-interface command in EIGRP suppresses the exchange of hello packets between two routers, which results in the loss of their neighbor relationship. This stops not only routing updates from being advertised, but it also suppresses incoming routing updates. This document also discusses the configuration required in order to allow the suppression of outgoing routing updates, while it also allows incoming routing updates to be learned normally from the neighbor. 

Q2. - (Topic 5) 

Refer to the exhibit. 

After the power-on-self test (POST), the system LED of a Cisco 2950 switch turns amber. What is the status of the switch? 

A. The POST was successful. 

B. The switch has a problem with the internal power supply and needs an external power supply to be attached. 

C. POST failed and there is a problem that prevents the operating system from being loaded. 

D. The switch has experienced an internal problem but data can still be forwarded at a slower rate. 

E. The switch passed POST, but all the switch ports are busy. 

Answer:

Explanation: 

http://www.cisco.com/en/US/products/hw/switches/ps607/products_tech_note09186a00801 25913.shtml 

Each time you power up the switch, eight Power-On Self Tests (POSTs) run automatically. POSTs check the most important system components before the switch begins to forward packets. When the switch begins the POST, the port status LEDs display amber for two seconds, and then display green. As each test runs, the port status LEDs go out. 1x is the first to go out. The port status LEDs for ports 2x through 8x go out sequentially as the system completes a test. When the POST completes successfully, the port status LEDs go out. This indicates that the switch is operational. If a test fails, the port status LED associated with the test displays amber. The system LED also displays amber. Not E: From Cisco IOS Software Release 11.2(8.5) SA6 onwards, the port and system LEDs both remain amber after a POST failure. In the earlier Cisco IOS Software Releases, only the LEDs of failed linked ports remained amber. 

Q3. - (Topic 3) 

If an Ethernet port on a router was assigned an IP address of 172.16.112.1/20, what is the maximum number of hosts allowed on this subnet? 

A. 1024 

B. 2046 

C. 4094 

D. 4096 

E. 8190 

Answer:

Explanation: 

Each octet represents eight bits. The bits, in turn, represent (from left to right): 128, 64, 32 , 16 , 8, 4, 2, 1 Add them up and you get 255. Add one for the all zeros option, and the total is 256. Now, take away one of these for the network address (all zeros) and another for the broadcast address (all ones). Each octet represents 254 possible hosts. Or 254 possible networks. Unless you have subnet zero set on your network gear, in which case you could conceivably have 255. The CIDR addressing format (/20) tells us that 20 bits are used for the network portion, so the maximum number of networks are 2^20 minus one if you have subnet zero enabled, or minus 2 if not. You asked about the number of hosts. That will be 32 minus the number of network bits, minus two. So calculate it as (2^(32-20))-2, or (2^12)-2 = 4094 

Q4. - (Topic 3) 

Which two of these functions do routers perform on packets? (Choose two.) 

A. Examine the Layer 2 headers of inbound packets and use that information to determine the next hops for the packets 

B. Update the Layer 2 headers of outbound packets with the MAC addresses of the next hops 

C. Examine the Layer 3 headers of inbound packets and use that information to determine the next hops for the packets 

D. Examine the Layer 3 headers of inbound packets and use that information to determine the complete paths along which the packets will be routed to their ultimate destinations 

E. Update the Layer 3 headers of outbound packets so that the packets are properly directed to valid next hops 

F. Update the Layer 3 headers of outbound packets so that the packets are properly directed to their ultimate destinations 

Answer: B,C 

Explanation: 

This is the basic function of the router to receive incoming packets and then forward them to their required destination. This is done by reading layer 3 headers of inbound packets and update the info to layer 2 for further hopping. 

Q5. - (Topic 2) 

Refer to the exhibit. 

The ports that are shown are the only active ports on the switch. The MAC address table is shown in its entirety. The Ethernet frame that is shown arrives at the switch. 

What two operations will the switch perform when it receives this frame? (Choose two.) 

A. The MAC address of 0000.00aa.aaaa will be added to the MAC address table. 

B. The MAC address of 0000.00dd.dddd will be added to the MAC address table. 

C. The frame will be forwarded out of port fa0/3 only. 

D. The frame will be forwarded out of fa0/1, fa0/2, and fa0/3. 

E. The frame will be forwarded out of all the active ports. 

Answer: A,D 

Explanation: 

If the switch already has the MAC address in its table for the destination, it will forward the frame directly to the destination port. If it was not already in its MAC table, then they frame would have been flooded out all ports except for the port that it came from. It will also add the MAC address of the source device to its MAC address table 

Q6. - (Topic 5) 

Refer to the exhibit. 

A user cannot reach any web sites on the Internet, but others in the department are not 

having a problem. 

What is the most likely cause of the problem? 

A. IP routing is not enabled. 

B. The default gateway is not in the same subnet. 

C. A DNS server address is not reachable by the PC. 

D. A DHCP server address is not reachable by the PC. 

E. NAT has not been configured on the router that connects to the Internet. 

Answer:

Explanation: 

Answer C is only answer that makes sense. IP routing does not need to be enabled on PC’s, this is a router function. We can see from the output that the PC and default gateway are on the same subnet. DHCP has not been enabled on this PC so it has been configured with a static address so reaching the DHCP server is not the issue. Finally, NAT must be configured correctly or the other users in the department would also be having issues. 

Q7. - (Topic 3) 

Refer to the exhibit. 

If the router Cisco returns the given output and has not had its router ID set manually, what value will OSPF use as its router ID? 

A. 192.168.1.1 

B. 172.16.1.1 

C. 1.1.1.1 

D. 2.2.2.2 

Answer:

Explanation: 

If a router-id is not configured manually in the OSPF routing process the router will automatically configure a router-id determined from the highest IP address of a logical interface (loopback interface) or the highest IP address of an active interface. If more than one loopback interfaces are configured, the router will compare the IP addresses of each of the interfaces and choose the highest IP address from the loopbacks. 

Q8. - (Topic 5) 

What is the bandwidth on the WAN interface of Router 1? 

A. 16 Kbit/sec 

B. 32 Kbit/sec 

C. 64 Kbit/sec 

D. 128 Kbit/sec 

E. 512 Kbit/sec 

F. 1544 Kbit/sec 

Answer:

Explanation: 

Use the “show interface s0/0” to see the bandwidth set at 16 Kbit/sec. The show interface s0/0 command results will look something like this and the bandwidth will be represented by the "BW" on the fourth line as seen below where BW equals 1544 Kbits/sec. R2#show interface serial 0/0 Serial0/0 is up, line protocol is down Hardware is GT96K Serial Internet address is 10.1.1.5/30 MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 uses. 

Q9. - (Topic 3) 

Refer to the exhibit. 

Which default gateway address should be assigned to HostA? 

A. 192.168.1.1 

B. 192.168.1.65 

C. 192.168.1.66 

D. 192.168.1.129 

E. 10.1.1.1 

F. 10.1.1.2 

Answer:

Explanation: 

The default gateway will be the IP address of the router that it connects to, not the switch. 

Q10. - (Topic 3) 

Which parameter or parameters are used to calculate OSPF cost in Cisco routers? 

A. Bandwidth 

B. Bandwidth and Delay 

C. Bandwidth, Delay, and MTU 

D. Bandwidth, MTU, Reliability, Delay, and Load 

Answer:

Explanation: 

The well-known formula to calculate OSPF cost is Cost = 108/ Bandwidth