200-105 Exam - Interconnecting Cisco Networking Devices Part 2 (ICND2 v3.0)

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Q1. - (Topic 3) 

Which command allows you to verify the encapsulation type (CISCO or IETF) for a Frame Relay link? 

A. show frame-relay lmi 

B. show frame-relay map 

C. show frame-relay pvc 

D. show interfaces serial 

Answer:

Explanation: map will show frame relay encapsulation (cisco or ietf) http://www.cisco.com/en/US/docs/ios/12_2/wan/command/reference/wrffr4.html#wp102934 

"show frame-relay map" will show frame relay encapsulation type (CISCO or IETF) 

Q2. - (Topic 2) 

What does a router do if it has no EIGRP feasible successor route to a destination network and the successor route to that destination network is in active status? 

A. It routes all traffic that is addressed to the destination network to the interface indicated in the routing table. 

B. It sends a copy of its neighbor table to all adjacent routers. 

C. It sends a multicast query packet to all adjacent neighbors requesting available routing paths to the destination network. 

D. It broadcasts Hello packets to all routers in the network to re-establish neighbor adjacencies. 

Answer:

Explanation: 

Introduction to EIGRP Reference: 

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. 

Route States 

A topology table entry for a destination can have one of two states. A route is considered in the Passive state when a router is not performing a route recomputation. The route is in Active state when a router is undergoing a route recomputation. If there are always feasible successors, a route never has to go into Active state and avoids a route recomputation. 

When there are no feasible successors, a route goes into Active state and a route recomputation occurs. A route recomputation commences with a router sending a query packet to all neighbors. Neighboring routers can either reply if they have feasible successors for the destination or optionally return a query indicating that they are performing a route recomputation. While in Active state, a router cannot change the next-hop neighbor it is using to forward packets. Once all replies are received for a given query, the destination can transition to Passive state and a new successor can be selected. 

When a link to a neighbor that is the only feasible successor goes down, all routes through that neighbor commence a route recomputation and enter the Active state. 

Q3. - (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:

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 

Q4. - (Topic 2) 

Refer to the exhibit. 

When running EIGRP, what is required for RouterA to exchange routing updates with RouterC? 

A. AS numbers must be changed to match on all the routers 

B. Loopback interfaces must be configured so a DR is elected 

C. The no auto-summary command is needed on Router A and Router C 

D. Router B needs to have two network statements, one for each connected network 

Answer: A Explanation: 

Here we required same autonomous system between router A,B,C.Routing updated always exchange between in same EIGRP EIGRP autonomous system.you can configure more than one EIGRP autonomous system on the same router. This is typically done at a redistribution point where two EIGRP autonomous systems are interconnected. Individual router interfaces should only be included within a single EIGRP autonomous system. Cisco does not recommend running multiple EIGRP autonomous systems on the same set of interfaces on the router. If multiple EIGRP autonomous systems are used with multiple points of mutual redistribution, it can cause discrepancies in the EIGRP topology table if correct filtering is not performed at the redistribution points. If possible, Cisco recommends you configure only one EIGRP autonomous system in any single autonomous system. http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f07.shtml 

Q5. - (Topic 3) 

What does the frame-relay interface-dlci command configure? 

A. local DLCI on the subinterface 

B. remote DLCI on the main interface 

C. remote DCLI on the subinterface 

D. local DLCI on the main interface 

Answer:

Explanation: 

Frame Relay for ICND Exam http://www.ciscopress.com/articles/article.asp?p=100603&seqNum=3 

To assign a data-link connection identifier (DLCI) to a specified Frame Relay subinterface on the router or access server, or to assign a specific permanent virtual circuit (PVC) to a DLCI, or to apply a virtual template configuration for a PPP session, use the frame-relay interface-dlci interface configuration command Example 4-23 Example of frame-relay interface-dlci Command and the Output of show frame-relay map R4(config)#interface s1/2.403 point-to-point R4(config-subif)#frame-relay interface-dlci ? <16-1007> Define a switched or locally terminated DLCI R4(config-subif)#frame-relay interface-dlci 403 ? cisco Use CISCO Encapsulation ietf Use RFC1490/RFC2427 Encapsulation 

ppp Use RFC1973 Encapsulation to support PPP over FR protocol Optional protocol information for remote end <cr> R4#show frame-relay map Serial1/2.403 (up): point-to-point dlci, dlci 403(0xC9,0x3090), broadcast status defined, active R4# 

Q6. - (Topic 2) 

Which parameter would you tune to affect the selection of a static route as a backup, when a dynamic protocol is also being used? 

A. hop count 

B. administrative distance 

C. link bandwidth 

D. link delay 

E. link cost 

Answer:

Explanation: 

What Is Administrative Distance? 

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094195.shtml 

Administrative distance is the feature that routers use in order to select the best path. Administrative distance defines the reliability of a routing protocol. Each routing protocol is prioritized in order of most to least reliable (believable) with the help of an administrative distance value. Lowest Administrative distance will be chosen first. 

Q7. - (Topic 2) 

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: 

http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094e9e.sht ml#t6 

OSPF Cost 

The cost (also called metric) of an interface in OSPF is an indication of the overhead required to send packets across a certain interface. The cost of an interface is inversely proportional to the bandwidth of that interface. A higher bandwidth indicates a lower cost. There is more overhead (higher cost) and time delays involved in crossing a 56k serial line than crossing a 10M Ethernet line. The formula used to calculate the cost is: Cost= 10000 0000/bandwidth in bps 

For example, it will cost 10 EXP8/10 EXP7 = 10 to cross a 10M Ethernet line and will cost 10 EXP8/1544000 =64 to cross a T1 line. By default, the cost of an interface is calculated based on the bandwidth; you can force the cost of an interface with the ip ospf cost <value> interface sub configuration mode command. 

Q8. - (Topic 3) 

What occurs on a Frame Relay network when the CIR is exceeded? 

A. All TCP traffic is marked discard eligible. 

B. All UDP traffic is marked discard eligible and a BECN is sent. 

C. All TCP traffic is marked discard eligible and a BECN is sent. 

D. All traffic exceeding the CIR is marked discard eligible. 

Answer:

Explanation: 

Committed information rate (CIR): The minimum guaranteed data transfer rate agreed to by the Frame Relay switch. Frames that are sent in excess of the CIR are marked as discard eligible (DE) which means they can be dropped if the congestion occurs within the Frame Relay network. Note: In the Frame Relay frame format, there is a bit called Discard eligible (DE) bit that is used to identify frames that are first to be dropped when the CIR is exceeded. 

Q9. - (Topic 1) 

Which protocol provides a method of sharing VLAN configuration information between two Cisco switches? 

A. STP 

B. VTP 

C. 802.1Q 

D. RSTP 

Answer:

Explanation: 

Understanding VLAN Trunk Protocol (VTP) http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080094c52. shtml 

Introduction VLAN Trunk Protocol (VTP) reduces administration in a switched network. When you configure a new VLAN on one VTP server, the VLAN is distributed through all switches in the domain. This reduces the need to configure the same VLAN everywhere. VTP is a Cisco-proprietary protocol that is available on most of the Cisco Catalyst series products. 

Q10. - (Topic 2) 

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 R1 will be dropped. 

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

C. 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. 

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 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. 

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 so answers A, B and C are not correct. D is not correct too because 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.