Q61. - (Topic 3) 

What is the subnet address for the IP address 172.19.20.23/28? 

A. 172.19.20.0 

B. 172.19.20.15 

C. 172.19.20.16 

D. 172.19.20.20 

E. 172.19.20.32 

Answer:

Explanation: 

From the /28 we can get the following: 

Increment: 16 (/28 = 11111111.11111111.11111111.11110000) 

Network address: 172.19.20.16 (because 16 < 23) 

Broadcast address: 172.16.20.31 (because 31 = 16 + 16 – 1) 


Q62. - (Topic 7) 

When a router makes a routing decision for a packet that is received from one network and destined to another, which portion of the packet does if replace? 

A. Layer 2 frame header and trailer 

B. Layer 3 IP address 

C. Layer 5 session 

D. Layer 4 protocol 

Answer:

Explanation: 

Router Switching Function (1.2.1.1)A primary function of a router is to forward packets toward their destination. This is accomplished by using a switching function, which is the process used by a router to accept a packet on one interface and forward it out of another interface. A key responsibility of the switching function is to encapsulate packets in the appropriate data link frame type for the outgoing data link. NOTE In this context, the term “switching” literally means moving packets from source to destination and should not be confused with the function of a Layer 2 switch. After the router has determined the exit interface using the path determination function, the router must encapsulate the packet into the data link frame of the outgoing interface. What does a router do with a packet received from one network and destined for another network? The router performs the following three major steps: 

. Step 1. De-encapsulates the Layer 3 packet by removing the Layer 2 frame header and trailer. . Step 2. Examines the destination IP address of the IP packet to find the best path in the routing table. . Step 3. If the router finds a path to the destination, it encapsulates the Layer 3 packet into a new Layer 2 frame and forwards the frame out the exit interface. 


Q63. - (Topic 1) 

Which network device functions only at Layer 1 of the OSI model? A. Option A 

B. Option B 

C. Option C 

D. Option D 

E. Option E 

Answer:

Explanation: 

Most hubs are amplifying the electrical signal; therefore, they are really repeaters with several ports. Hubs and repeaters are Layer 1 (physical layer) devices. 


Q64. - (Topic 3) 

The network manager has requested a 300-workstation expansion of the network. The workstations are to be installed in a single broadcast domain, but each workstation must have its own collision domain. The expansion is to be as cost-effective as possible while still meeting the requirements. 

Which three items will adequately fulfill the request? (Choose three). 

A. One IP subnet with a mask of 255.255.254.0 

B. Two IP subnets with a mask of 255.255.255.0 

C. Seven 48-port hubs 

D. Seven 48-port switches 

E. One router interface 

F. Seven router interfaces 

Answer: A,D,E 

Explanation: 

To support 300 workstations in a single broadcast domain, we need to use a subnet mask 

which supports 512 hosts = 29-> /23 or 255.255.254.0 in decimal form -> A is correct. 

If we use 48-port switches we need 300/48 = 6.25 -> seven 48-port switches are enough 

because we also need trunking between them -> D is correct. 

We only need one router interface and it is connected with one of seven switches -> E is 

correct. 


Q65. - (Topic 5) 

An administrator has connected devices to a switch and, for security reasons, wants the dynamically learned MAC addresses from the address table added to the running configuration. 

What must be done to accomplish this? 

A. Enable port security and use the keyword sticky. 

B. Set the switchport mode to trunk and save the running configuration. 

C. Use the switchport protected command to have the MAC addresses added to the configuration. 

D. Use the no switchport port-security command to allow MAC addresses to be added to the configuration. 

Answer:

Explanation: 

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide 

/port_sec.pdf 

One can configure MAC addresses to be sticky. These can be dynamically learned or manually configured, stored in the address table, and added to the running configuration. If these addresses are saved in the configuration file, the interface does not need to dynamically relearn them when the switch restarts, hence enabling security as desired. 


Q66. - (Topic 3) 

Which characteristics are representative of a link-state routing protocol? (Choose three.) 

A. provides common view of entire topology 

B. exchanges routing tables with neighbors C. calculates shortest path 

D. utilizes event-triggered updates 

E. utilizes frequent periodic updates 

Answer: A,C,D 

Explanation: 

Each of routers running link-state routing protocol learns paths to all the destinations in its 

“area” so we can say although it is a bit unclear. 

Link-state routing protocols generate routing updates only (not the whole routing table) 

when a change occurs in the network topology so 

Link-state routing protocol like OSPF uses Dijkstra algorithm to calculate the shortest path -> . 

Unlike Distance vector routing protocol (which utilizes frequent periodic updates), link-state 

routing protocol utilizes event-triggered updates (only sends update when a change occurs) 

-> 


Q67. - (Topic 3) 

Which command enables IPv6 forwarding on a Cisco router? 

A. ipv6 host 

B. ipv6 unicast-routing 

C. ipv6 local 

D. ipv6 neighbor 

Answer:

Explanation: 

Enabling IPv6 on Cisco IOS Software Technology http://www.ciscopress.com/articles/article.asp?p=31948&seqNum=4 The first step of enabling IPv6 on a Cisco router is the activation of IPv6 traffic forwarding to forward unicast IPv6 packets between network interfaces. By default, IPv6 traffic forwarding is disabled on Cisco routers. The ipv6 unicast-routing command is used to enable the forwarding of IPv6 packets between interfaces on the router. The syntax for this command is as follows: Router(config)#ipv6 unicast-routing The ipv6 unicast-routing command is enabled on a global basis. 


Q68. - (Topic 3) 

Refer to the exhibit. 

If the resume command is entered after the sequence that is shown in the exhibit, which router prompt will be displayed? 

A. Router1> 

B. Router1# 

C. Router2> 

D. Router2# 

Answer:

Explanation: 

After resuming the telnet session by using the Enter key after it has been suspended, it will resume back to the telnet session so it will be back to the router2> prompt. 


Q69. - (Topic 5) 

Refer to the exhibit. 

Serial 0/0 does not respond to a ping request from a host on the FastEthernet 0/0 LAN. How can this problem be corrected? 

A. Enable the Serial 0/0 interface. 

B. Correct the IP address for Serial 0/0. 

C. Correct the IP address for FastEthernet 0/0 

D. Change the encapsulation type on Serial 0/0 

E. Enable autoconfiguration on the Serial 0/0 interface 

Answer:

Explanation: 

Serial 0/0 interface is administratively down therefore, you will have to run the "no shutdown" command to enable the interface for data. 


Q70. - (Topic 1) 

Which OSI layer header contains the address of a destination host that is on another network? 

A. application 

B. session 

C. transport 

D. network 

E. data link 

F. physical 

Answer:

Explanation: 

Only network address contains this information. To transmit the packets the sender uses network address and datalink address. But the layer 2 address represents just the address of the next hop device on the way to the sender. It is changed on each hop. Network address remains the same.