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Q1. - (Topic 7) 

Which value is indicated by the next hop in a routing table? 

A. preference of the route source 

B. IP address of the remote router for forwarding the packets 

C. how the route was learned 

D. exit interface IP address for forwarding the packets 

Answer:

Explanation: 

The routing table contains network/next hop associations. These associations tell a router that a particular destination can be optimally reached by sending the packet to a specific router that represents the "next hop" on the way to the final destination. The next hop association can also be the outgoing or exit interface to the final destination. 

Q2. - (Topic 4) 

What happens when computers on a private network attempt to connect to the Internet through a Cisco router running PAT? 

A. The router uses the same IP address but a different TCP source port number for each connection. 

B. An IP address is assigned based on the priority of the computer requesting the connection. 

C. The router selects an address from a pool of one-to-one address mappings held in the lookup table. 

D. The router assigns a unique IP address from a pool of legally registered addresses for the duration of the connection. 

Answer:

Reference: 

http://www.cisco.com/en/US/docs/security/asa/asa82/configuration/guide/nat_staticpat.html 

Static PAT translations allow a specific UDP or TCP port on a global address to be translated to a specific port on a local address. That is, both the address and the port numbers are translated. 

Static PAT is the same as static NAT, except that it enables you to specify the protocol (TCP or UDP) and port for the real and mapped addresses. Static PAT enables you to identify the same mapped address across many different static statements, provided that the port is different for each statement. You cannot use the same mapped address for multiple static NAT statements. 

Port Address Translation makes the PC connect to the Internet but using different TCP source port. 

Q3. - (Topic 1) 

Refer to the exhibit. 

HostX is transferring a file to the FTP server. Point A represents the frame as it goes toward the Toronto router. What will the Layer 2 destination address be at this point? 

A. abcd.1123.0045 

B. 192.168.7.17 

C. aabb.5555.2222 

D. 192.168.1.1 

E. abcd.2246.0035 

Answer:

Explanation: 

For packets destined to a host on another IP network, the destination MAC address will be the LAN interface of the router. Since the FTP server lies on a different network, the host will know to send the frame to its default gateway, which is Toronto. 

Q4. - (Topic 3) 

What information can be used by a router running a link-state protocol to build and maintain its topological database? (Choose two.) 

A. hello packets 

B. SAP messages sent by other routers 

C. LSAs from other routers 

D. beacons received on point-to-point links 

E. routing tables received from other link-state routers 

F. TTL packets from designated routers 

Answer: A,C 

Explanation: 

Reference 1: http://www.ciscopress.com/articles/article.asp?p=24090&seqNum=4 

Link state protocols, sometimes called shortest path first or distributed database protocols, are built around a well-known algorithm from graph theory, E. W. Dijkstra'a shortest path algorithm. Examples of link state routing protocols are: Open Shortest Path First (OSPF) for IP The ISO's Intermediate System to Intermediate System (IS-IS) for CLNS and IP DEC's DNA Phase V Novell's NetWare Link Services Protocol (NLSP) Although link state protocols are rightly considered more complex than distance vector protocols, the basic functionality is not complex at all: 

1.

 Each router establishes a relationship—an adjacency—with each of its neighbors. 

2.

 Each router sends link state advertisements (LSAs), some 

3.

 Each router stores a copy of all the LSAs it has seen in a database. If all works well, the databases in all routers should be identical. 

4.

 The completed topological database, also called the link state database, describes a graph of the internetwork. Using the Dijkstra algorithm, each router calculates the shortest path to each network and enters this information into the route table. OSPF Tutorial 

Q5. - (Topic 3) 

What are two benefits of using a single OSPF area network design? (Choose two.) 

A. It is less CPU intensive for routers in the single area. 

B. It reduces the types of LSAs that are generated. 

C. It removes the need for virtual links. 

D. It increases LSA response times. 

E. It reduces the number of required OSPF neighbor adjacencies. 

Answer: B,C 

Explanation: 

OSPF uses a LSDB (link state database) and fills this with LSAs (link state advertisement). The link types are as follows: 

. LSA Type 1: Router LSA 

....... 

LSA Type 2: Network LSA 

LSA Type 3: Summary LSA 

LSA Type 4: Summary ASBR LSA 

LSA Type 5: Autonomous system external LSA 

LSA Type 6: Multicast OSPF LSA 

LSA Type 7: Not-so-stubby area LSA 

LSA Type 8: External attribute LSA for BGP 

If all routers are in the same area, then many of these LSA types (Summary ASBR LSA, external LSA, etc) will not be used and will not be generated by any router. 

All areas in an Open Shortest Path First (OSPF) autonomous system must be physically connected to the backbone area (Area 0). In some cases, where this is not possible, you can use a virtual link to connect to the backbone through a non-backbone area. You can also use virtual links to connect two parts of a partitioned backbone through a non-backbone area. The area through which you configure the virtual link, known as a transit area, must have full routing information. The transit area cannot be a stub area. Virtual links are not ideal and should really only be used for temporary network solutions or migrations. However, if all locations are in a single OSPF area this is not needed. 

Q6. - (Topic 3) 

What is the network address for the host with IP address 192.168.23.61/28? 

A. 192.168.23.0 

B. 192.168.23.32 

C. 192.168.23.48 

D. 192.168.23.56 

E. 192.168.23.60 

Answer:

Explanation: 

Convert bit-length prefix to quad-dotted decimal representation, then from it find the number of bits used for subnetting you can find previously calculated number of subnets by separating subnets each having value of last bit used for subnet masking Find that your IP address is in which subnet, that subnet's first address is network address and last address is broadcast address. Based on above steps the answer is option C 

Q7. - (Topic 3) 

Refer to the exhibit. 

Assume that all router interfaces are operational and correctly configured. In addition, assume that OSPF has been correctly configured on router R2. How will the default route configured on R1 affect the operation of R2? 

A. Any packet destined for a network that is not directly connected to router R2 will be dropped immediately. 

B. Any packet destined for a network that is not referenced in the routing table of router R2 will be directed to R1. R1 will then send that packet back to R2 and a routing loop will occur. 

C. Any packet destined for a network that is not directly connected to router R1 will be dropped. 

D. The networks directly connected to router R2 will not be able to communicate with the 172.16.100.0, 172.16.100.128, and 172.16.100.64 subnetworks. 

E. Any packet destined for a network that is not directly connected to router R2 will be dropped immediately because of the lack of a gateway on R1. 

Answer:

Explanation: 

First, notice that the more-specific routes will always be favored over less-specific routes regardless of the administrative distance set for a protocol. In this case, because we use OSPF for three networks (172.16.100.0 0.0.0.3, 172.16.100.64 0.0.0.63, 172.16.100.128 0.0.0.31) so the packets destined for these networks will not be affected by the default route. The default route configured on R1 “ip route 0.0.0.0 0.0.0.0 serial0/0 will send any packet whose destination network is not referenced in the routing table of router R1 to R2, it doesn’t drop anything. These routes are declared in R1 and the question says that “OSPF has been correctly configured on router R2, so network directly connected to router R2 can communicate with those three subnetworks. As said above, the default route configured on R1 will send any packet destined for a network that is not referenced in its routing table to R2; R2 in turn sends it to R1 because it is the only way and a routing loop will occur. 

Q8. - (Topic 7) 

Which component of the routing table ranks routing protocols according to their preferences? 

A. administrative distance 

B. next hop 

C. metric 

D. routing protocol code 

Answer:

Explanation: 

Administrative distance - This is the measure of trustworthiness of the source of the 

route. If a router learns about a destination from more than one routing protocol, 

administrative distance is compared and the preference is given to the routes with lower 

administrative distance. In other words, it is the believability of the source of the route. 

Q9. - (Topic 4) 

What is the best practice when assigning IP addresses in a small office of six hosts? 

A. Use a DHCP server that is located at the headquarters. 

B. Use a DHCP server that is located at the branch office. 

C. Assign the addresses by using the local CDP protocol. 

D. Assign the addresses statically on each node. 

Answer:

Explanation: 

Its best to use static addressing scheme where the number of systems is manageable rather than using a dynamic method such as DHCP as it is easy to operate and manage. 

Q10. - (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.