Q1. - (Topic 2)
Which type of EIGRP route entry describes a feasible successor?
A. a backup route, stored in the routing table
B. a primary route, stored in the routing table
C. a backup route, stored in the topology table
D. a primary route, stored in the topology table
Answer: C
Explanation:
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. Feasible successor is a route whose Advertised Distance (AD) is less than the Feasible Distance (FD) of the current best path. A feasible successor is a backup route, which is not stored in the routing table but, stored in the topology table.
Q2. - (Topic 3)
Refer to the exhibit.
The show interfaces serial 0/1 command was issued on the R10-1 router. Based on the output displayed which statement is correct?
A. The cable connected to the serial 0/1 interface of the R10-1 router is a DTE cable.
B. The R10-1 router can ping the router interface connected to the serial 0/1 interface.
C. The clock rate used for interface serial 0/1 of the R10-1 router is 1,544,000 bits per second.
D. The CSU used with the serial 0/1 interface of the R10-1 router has lost connection to the service provider.
E. The interface of the remote router connected to the serial 0/1 interface of the R10-1 router is using the default serial interface encapsulation.
Answer: E
Explanation:
Cisco High-Level Data Link Controller (HDLC) is the Cisco proprietary protocol for Cisco HDLC is the default encapsulation type for the serial interfaces.
Q3. DRAG DROP - (Topic 2)
Answer:
Explanation:
Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco proprietary routing protocol, so it is vendor-specific. By default, EIGRP internal routes have an administrative distance value of 90. OSPF uses cost as its metric. By default, the cost of an interface is calculated based on bandwidth with the formula cost= 10000 0000/bandwidth (in bps). OSPF elects a DR on each broadcast and nonbroadcast multiaccess networks (like Ethernet and Frame Relay environments, respectively). It doesn’t elect a DR on point-to-point link (like a serial WAN).
Q4. - (Topic 2)
Which two are advantages of static routing when compared to dynamic routing? (Choose two.)
A. Configuration complexity decreases as network size increases.
B. Security increases because only the network administrator may change the routing table.
C. Route summarization is computed automatically by the router.
D. Routing tables adapt automatically to topology changes.
E. An efficient algorithm is used to build routing tables, using automatic updates.
F. Routing updates are automatically sent to neighbors.
G. Routing traffic load is reduced when used in stub network links.
Answer: B,G
Explanation:
When reading (or being lectured about) all the glorious details of dynamic routing protocols, it's hard not to come away with the impression that dynamic routing is always better than static routing. It's important to keep in mind that the primary duty of a dynamic routing protocol is to automatically detect and adapt to topological changes in the internetwork. The price of this "automation" is paid in bandwidth, security, and maybe queue space, in memory, and in processing time. A frequent objection to static routing is that it is hard to administer. This criticism may be true of medium to large topologies with many alternative routes, but it is certainly not true of small internetworks with few or no alternative routes. References: http://www.ciscopress.com/articles/article.asp?p=24090&seqNum=6 http://www.ciscopress.com/articles/article.asp?p=24090
Q5. - (Topic 3)
Refer to the exhibit.
A network associate has configured OSPF with the command: City(config-router)# network 192.168.12.64 0.0.0.63 area 0 After completing the configuration, the associate discovers that not all the interfaces are participating in OSPF. Which three of the interfaces shown in the exhibit will participate in OSPF according to this configuration statement? (Choose three.)
A. FastEthernet0 /0
B. FastEthernet0 /1
C. Serial0/0
D. Serial0/1.102
E. Serial0/1.103
F. Serial0/1.104
Answer: B,C,D
Explanation:
The “network 192.168.12.64 0.0.0.63 equals to network 192.168.12.64/26. This network has:Increment: 64 (/26= 1111 1111.1111 1111.1111 1111.1100 0000)Network address:
192.168.12.64 Broadcast address: 192.168.12.127Therefore all interface in the range of this network will join OSPF - B C D are correct.
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: B
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)
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: C
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.
Q8. - (Topic 2)
Refer to the exhibit.
The network associate is configuring OSPF on the Core router. All the connections to the branches should be participating in OSPF. The link to the ISP should NOT participate in OSPF and should only be advertised as the default route. What set of commands will properly configure the Core router?
A. Core(config-router)# default-information originate Core(config-router)# network 10.0.0.0 0.255.255.255 area 0 Core(config-router)# exit Core(config)# ip route 0.0.0.0 0.0.0.0 10.10.2.14
B. Core(config-router)# default-information originate Core(config-router)# network 10.10.2.13 0.0.0.242 area 0 Core(config-router)# exit Core(config)# ip route 0.0.0.0 0.0.0.0 10.10.2.14
C. Core(config-router)# default-information originate Core(config-router)# network 10.10.2.16 0.0.0.15 area 0 Core(config-router)# exit Core(config)# ip route 0.0.0.0 0.0.0.0 10.10.2.14
D. Core(config-router)# default-information originate Core(config-router)# network 10.10.2.32 0.0.0.31 area 0 Core(config-router)# exit Core(config)# ip route 0.0.0.0 0.0.0.0 10.10.2.14
Answer: C
Explanation:
There are two ways to inject a default route into a normal area.1. If the ASBR already has the default route in its routing table, you can advertise theexisting 0.0.0.0/0 into the OSPF domain with the default-information originate router configuration command.2. If the ASBR doesn’t have a default route, you can add the keyword always to the default-information originate command (default-information originate always).This command will advertise a default route into the OSPF domain, regardless of whether it has a route to 0.0.0.0. Another benefit of adding always keyword is that it can add stability to the internetwork. For example, if the ASBR is learning a default route from another routing domain such as RIP and this route is flapping, then without the always keyword, each time the route flaps, the ASBR will send a new Type 5 LSA into the OSPF domain causing some instability inside the OSPF domain. With the always keyword, the ASBR will advertise the default inside the OSPF domain always, In the example shown here, only choice C is correct as the wildcard mask correctly specifies the 10.10.2.16 0.0.0.15 networks, which include all IP addresses in the 10.10.2.16-10.10.2.31 range. In this question we were told that the ISP link should NOT be configured for OSPF, making choice A incorrect. http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801 ec9f0.shtml
Q9. - (Topic 3)
What is the purpose of Inverse ARP?
A. to map a known IP address to a MAC address
B. to map a known DLCI to a MAC address
C. to map a known MAC address to an IP address
D. to map a known DLCI to an IP address
E. to map a known IP address to a SPID
F. to map a known SPID to a MAC address
Answer: D
Explanation:
http://www.ciscopress.com/articles/article.asp?p=170741&seqNum=4
Frame-Relay (a Layer 2 protocol) uses Inverse-Arp to map a know Layer 2 Address (DLCI) to a unknow Layer 3 Address. Dynamic Mapping Dynamic address mapping relies on the Frame Relay Inverse Address Resolution Protocol (Inverse ARP), defined by RFC 1293, to resolve a next hop network protocol address to a local DLCI value. The Frame Relay router sends out Inverse ARP requests on its Frame Relay PVC to discover the protocol address of the remote device connected to the Frame Relay network. The responses to the Inverse ARP requests are used to populate an address-to-DLCI mapping table on the Frame Relay router or access server. The router builds and maintains this address-to-DLCI mapping table, which contains all resolved Inverse ARP requests, including both dynamic and static mapping entries. When data needs to be transmitted to a remote destination address, the router performs a lookup on its routing table to determine whether a route to that destination address exists and the next hop address or directly connected interface to use in order to reach that destination. Subsequently, the router consults its address-to-DLCI mapping table for the local DLCI that corresponds to the next hop address. Finally, the router places the frames targeted to the remote destination on its identified outgoing local DLCI. On Cisco routers, dynamic Inverse ARP is enabled by default for all network layer protocols enabled on the physical interface. Packets are not sent out for network layer protocols that are not enabled on the physical interface. For example, no dynamic Inverse ARP resolution is performed for IPX if ipx routing is not enabled globally and there is no active IPX address assigned to the interface. Because dynamic Inverse ARP is enabled by default, no additional Cisco IOS command is required to enable it on an interface. Example 4-16 shows the output of the show frame-relay map privileged EXEC mode command. The addressto-DLCI mapping table displays useful information. The output of the command shows that the next hop address 172.16.1.2 is dynamically mapped to the local DLCI 102, broadcast is enabled on the interface, and the interface's status is currently active.
NOTE After enabling Frame Relay on the interface, the Cisco router does not perform Inverse ARP until IP routing is enabled on the router. By default, IP routing is enabled on a Cisco router. If IP routing has been turned off, enable IP routing with the ip routing command in the global configuration mode. After IP routing is enabled, the router performs Inverse ARP and begins populating the address-to-DLCI mapping table with resolved entries.
Q10. - (Topic 2)
Refer to the exhibit.
The Lakeside Company has the internetwork in the exhibit. The administrator would like to reduce the size of the routing table on the Central router. Which partial routing table entry in the Central router represents a route summary that represents the LANs in Phoenix but no additional subnets?
A. 10.0.0.0/22 is subnetted, 1 subnets D 10.0.0.0 [90/20514560] via 10.2.0.2, 6w0d, Serial0/1
B. 10.0.0.0/28 is subnetted, 1 subnets D 10.2.0.0 [90/20514560] via 10.2.0.2, 6w0d, Serial0/1
C. 10.0.0.0/30 is subnetted, 1 subnets D 10.2.2.0 [90/20514560] via 10.2.0.2, 6w0d, Serial0/1
D. 10.0.0.0/22 is subnetted, 1 subnets D 10.4.0.0 [90/20514560] via 10.2.0.2, 6w0d, Serial0/1
E. 10.0.0.0/28 is subnetted, 1 subnets D 10.4.4.0 [90/20514560] via 10.2.0.2, 6w0d, Serial0/1
F. 10.0.0.0/30 is subnetted, 1 subnets D 10.4.4.4 [90/20514560] via 10.2.0.2, 6w0d, Serial0/1
Answer: D
Explanation:
All the above networks can be summarized to 10.0.0.0 network but the question requires to “represent the LANs in Phoenix but no additional subnets” so we must summarized to
10.4.0.0 network. The Phoenix router has 4 subnets so we need to “move left” 2 bits of “/24-> /22 is the best choice - D is correct.
Q11. - (Topic 3)
At which layer of the OSI model does PPP perform?
A. Layer 2
B. Layer 3
C. Layer 4
D. Layer 5
Answer: A
Explanation:
Point-to-Point Protocol (PPP) is a data link protocol commonly used in establishing a direct connection between two networking nodes. It can provide connection authentication, transmission encryption (using ECP, RFC 1968), and compression.
Q12. - (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: E
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.
Q13. - (Topic 3)
What command is used to verify the DLCI destination address in a Frame Relay static configuration?
A. show frame-relay pvc
B. show frame-relay lmi
C. show frame-relay map
D. show frame relay end-to-end
Answer: C
Explanation:
Cisco Frame Relay Configurations http://www.ciscopress.com/articles/article.asp?p=170741&seqNum=9 show frame-relay map The show frame-relay map privileged EXEC mode command shows the contents of the next hop protocol address to DLCI mapping table on the router. The table contains both dynamic mapped and static mapped entries. The below example shows a sample output of the show frame-relay map command. Router#show frame-relay map Serial1/2 (up): ip 172.16.1.4 dlci 401(0x191,0x6410), dynamic, broadcast,, status defined, active Serial1/2 (up): ip 172.16.1.5 dlci 501(0x1F5,0x7C50), dynamic, broadcast,, status defined, active Serial1/2 (up): ip 172.16.1.2 dlci 301(0x12D,0x48D0), dynamic, broadcast,, status defined, active
Q14. - (Topic 2)
What are two enhancements that OSPFv3 supports over OSPFv2? (Choose two.)
A. It requires the use of ARP.
B. It can support multiple IPv6 subnets on a single link.
C. It supports up to 2 instances of OSPFv3 over a common link.
D. It routes over links rather than over networks.
Answer: B,D Explanation:
Here is a list of the differences between OSPFv2 and OSPFv3:
They use different address families (OSPFv2 is for IPv4-only, OSPFv3 can be used for IPv6-only or both protocols OSPFv3 introduces new LSA types OSPFv3 has different packet format OSPFv3 uses different flooding scope bits (U/S2/S1) OSPFv3 adjacencies are formed over link-local IPv6 communications OSPFv3 runs per-link rather than per-subnet OSPFv3 supports multiple instances on a single link, Interfaces can have multiple IPv6 addresses OSPFv3 uses multicast addresses FF02::5 (all OSPF routers), FF02::6 (all OSPF DRs) OSPFv3 Neighbor Authentication done with IPsec (AH) OSPFv2 Router ID (RID) must be manually configured, still a 32-bit number
Reference: http://www.networkworld.com/article/2225270/cisco-subnet/ospfv3-for-ipv4-and-ipv6.html
Q15. - (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: A
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#
Q16. - (Topic 3)
What are three reasons that an organization with multiple branch offices and roaming users might implement a Cisco VPN solution instead of point-to-point WAN links? (Choose three.)
A. reduced cost
B. better throughput
C. broadband incompatibility
D. increased security
E. scalability
F. reduced latency
Answer: A,D,E
Explanation: Cisco VPN solutions provide exceptional security through encryption and authentication technologies that protect data in transit from unauthorized access and attacks. A Cisco VPN helps you: Use highly secure communications, with access rights tailored to individual users Quickly add new sites or users, without significantly expanding your existing infrastructure Improve productivity by extending corporate networks, applications, and collaboration tools Reduce communications costs while increasing flexibility