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Q241. Which two statements about route summarization are true? (Choose two.)

A. RIP, IGRP, and EIGRP can automatically summarize routing information at network address boundaries. 

B. EIGRP can automatically summarize external routes. 

C. The area range command can aggregate addresses on the ASBR. 

D. The summary-address command under the router process configures manual summarization on RIPv2 devices. 

E. The ip classless command enables classful protocols to select a default route to an unknown subnet on a network with other known subnets. 

Answer: A,E 


Q242. Which two statements about logging are true? (Choose two.) 

A. Log messages are sent to the console port by default. 

B. Log messages are displayed in a Telnet session by default. 

C. Interface status changes are logged at the Notification level. 

D. Interface status changes are logged at the Informational level. 

E. System restart messages are logged at the Critical level. 

F. Reload requests are logged at the Notification level. 

Answer: A,C 

Explanation: 

By default, switches send the output from system messages and debug privileged EXEC commands to a logging process. The logging process controls the distribution of logging messages to various destinations, such as the logging buffer, terminal lines, or a UNIX syslog server, depending on your configuration. The process also sends messages to the console. 

Table 29-3 Message Logging Level Keywords 

Level Keyword 

Level 

Description 

Syslog Definition 

emergencies 

System unstable 

LOG_EMERG 

alerts 

Immediate action needed 

LOG_ALERT 

critical 

Critical conditions 

LOG_CRIT 

errors 

Error conditions

LOG_ERR 

warnings 

Warning conditions 

LOG_WARNING 

notifications 

Normal but significant condition 

LOG_NOTICE 

informational 

Informational messages only 

LOG_INFO 

debugging 

Debugging messages 

LOG_DEBUG 

The software generates four other categories of messages: 

. Error messages about software or hardware malfunctions, displayed at levels warnings through emergencies. These types of messages mean that the functionality of the switch is affected. For information on how to recover from these malfunctions, see the system message guide for this release. 

. Output from the debug commands, displayed at the debugging level. Debug commands are typically used only by the Technical Assistance Center. 

Interface up or down transitions and system restart messages, displayed at the notifications level. This message is only for information; switch functionality is not affected. 

. Reload requests and low-process stack messages, displayed at the informational level. This message is only for information; switch functionality is not affected. 

References: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2950/software/release/12-

1_9_ea1/configuration/guide/scg/swlog.html

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960/software/release/12-2_55_se/configuration/guide/scg_2960/swlog.html 


Q243. Which three statements about EIGRP and BFD are true? (Choose three.) 

A. BFD is independent of the routing protocol, so it can be used as a generic failure detection mechanism for EIGRP. 

B. Some parts of BFD can be distributed to the data plane, so it can be less CPU-intensive than reduced timers, which exist wholly at the control plane. 

C. Reduced EIGRP timers have an absolute minimum detection timer of 1-2 seconds; BFD can provide sub-second failure detection. 

D. BFD is tied to specific routing protocols and can be used for generic fault detection for the OSPF, EIGRP, and BGP routing protocols. 

E. BFD is dependent on the EIGRP routing protocol, so it can be used as a specific failure detection mechanism. 

F. BFD resides on the control plane, so it is less CPU-intensive than if it resided on the data plane. 

Answer: A,B,C 

Explanation: 

There are several advantages to implementing BFD over reduced timer mechanisms for routing protocols: 

. Although reducing the EIGRP, IS-IS, and OSPF timers can result in minimum detection timer of one to two seconds, BFD can provide failure detection in less than one second. 

. Because BFD is not tied to any particular routing protocol, it can be used as a generic and consistent failure detection mechanism for EIGRP, IS-IS, and OSPF. 

. Because some parts of BFD can be distributed to the data plane, it can be less CPU-intensive than the reduced EIGRP, IS-IS, and OSPF timers, which exist wholly at the control plane. 

Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/fs_bfd.html 


Q244. An access switch at a remote location is connected to the spanning-tree root with redundant uplinks. A network engineer notices that there are issues with the physical cabling of the current root port. The engineer decides to force the secondary link to be the desired forwarding root port. Which action accomplishes this task? 

A. Adjust the secondary link to have a lower priority than the primary link. 

B. Change the link type to point-to-point. 

C. Apply a BPDU filter on the primary interface of the remote switches. 

D. Enable Rapid Spanning Tree to converge using the secondary link. 

Answer:


Q245. How does EIGRP derive the metric for manual summary routes? 

A. It uses the best composite metric of any component route in the topology table. 

B. It uses the worst composite metric of any component route in the topology table. 

C. It uses the best metric vectors of all component routes in the topology table. 

D. It uses the worst metric vectors of all component routes in the topology table. 

Answer:

Explanation: 

For example if your router has a routing table like this: 

D 192.168.8.0/24 [90/2632528] via 192.168.0.1, 00:00:12, Serial0/0 

D 192.168.9.0/24 [90/2323456] via 192.168.0.1, 00:00:12, Serial0/0 

D 192.168.10.0/24 [90/2195456] via 192.168.0.1, 00:00:12, Serial0/0 

D 192.168.11.0/24 [90/2323456] via 192.168.0.1, 00:00:12, Serial0/0 

Now suppose you want to manually summarize all the routes above, you can use this command (on the router that advertised these routes to our router): 

Router(config-if)#ip summary-address eigrp 1 192.168.8.0 255.255.248.0 

After that the routing table of your router will look like this: 

D 192.168.8.0/21 [90/2195456] via 192.168.0.1, 00:01:42, Serial0/0 

And we can see the manual summary route takes the smallest metric of the specific routes. 


Q246. Which two attributes were introduced with the Cisco IOS BGP 4-byte ASN feature? (Choose two.) 

A. AS4_AGGREGATOR 

B. AS4_PATH 

C. AS4_PLAIN 

D. AS4_DOT 

E. AS4_TRANS 

Answer: A,B 


Q247. Independent, multiple OSPF processes are entered on the same router, and the processes have the same destination route. Which OSPF process is used? 

A. The route with the fewest hops is used. 

B. Both processes are used to load balance the traffic. 

C. The first route process that places a route into the routing table is used. 

D. The route with the shortest prefix is used. 

Answer:


Q248. Which statement describes what it means if a router has an OSPF priority set to 0? 

A. A router with the OSPF priority set to 0 is one that can participate in the election of a DR. It has the highest priority. 

B. A router with the OSPF priority set to 0 is one that cannot participate in the election of a DR, but it can become a BDR 

C. A router with the OSPF priority set to 0 is one that cannot participate in the election of a DR. It can become neither a DR nor a BDR. 

D. A router with the OSPF priority set to 0 is one that cannot participate in the election of a BDR, but it can become a DR 

Answer:


Q249. When you migrate a network from PVST+ to rapid-PVST+, which two features become inactive? (Choose two.) 

A. Root guard 

B. Loop guard 

C. UplinkFast 

D. UDLD 

E. BackboneFast 

F. Bridge Assurance 

Answer: C,E 

Explanation: 

It is good to know the UplinkFast and BackboneFast behavior before you start the migration process. 

Here, the Access1 switch runs Cisco IOS. This output is taken before migration to the rapid-PVST+ mode: 

Access1#show spanning-tree vlan 10 

VLAN0010 

Spanning tree enabled protocol ieee 

Root ID Priority 24586 

Address 0015.63f6.b700 

Cost 3019 

Port 107 (FastEthernet3/0/1) 

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec 

Bridge ID Priority 49162 (priority 49152 sys-id-ext 10) 

Address 000f.f794.3d00 

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec 

Aging Time 300 

Uplinkfast enabled 

Interface Role Sts Cost Prio.Nbr Type 

Fa3/0/1 Root FWD 3019 128.107 P2p 

Fa3/0/2 Altn BLK 3019 128.108 P2p 

Access1#show spanning-tree summary 

Switch is in pvst mode 

Root bridge for: none 

Extended system ID is enabled 

Portfast Default is disabled 

PortFast BPDU Guard Default is enabled 

Portfast BPDU Filter Default is disabled 

Loopguard Default is disabled 

EtherChannel misconfig guard is enabled 

UplinkFast is enabled 

BackboneFast is enabled 

Configured Pathcost method used is short 

Name Blocking Listening Learning Forwarding STP Active 

VLAN0010 1 0 0 1 2 

VLAN0020 1 0 0 1 2 

2 vlans 2 0 0 2 4 

This output is taken after the mode is changed to rapid-PVST+: 

Access1#show spanning-tree vlan 10 

VLAN0010 

Spanning tree enabled protocol rstp 

Root ID Priority 24586 

Address 0015.63f6.b700 

Cost 3019 

Port 107 (FastEthernet3/0/1) 

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec 

Bridge ID Priority 49162 (priority 49152 sys-id-ext 10) 

Address 000f.f794.3d00 

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec 

Aging Time 300 

UplinkFast enabled but inactive in rapid-pvst mode 

Interface Role Sts Cost Prio.Nbr Type 

Fa3/0/1 Root FWD 3019 128.107 P2p 

Fa3/0/2 Altn BLK 3019 128.108 P2p 

Access1#show spanning-tree summary 

Switch is in rapid-pvst mode 

Root bridge for: none 

Extended system ID is enabled 

Portfast Default is disabled 

PortFast BPDU Guard Default is enabled 

Portfast BPDU Filter Default is disabled 

Loopguard Default is disabled 

EtherChannel misconfig guard is enabled 

UplinkFast is enabled but inactive in rapid-pvst mode 

BackboneFast is enabled but inactive in rapid-pvst mode 

Configured Pathcost method used is short 

Name Blocking Listening Learning Forwarding STP Active 

VLAN0010 1 0 0 1 2 

VLAN0020 1 0 0 1 2 

2 vlans 2 0 0 2 4 

You can see in the show spanning-tree summary command output that UplinkFast and BackboneFast are enabled, but are inactive in rapid-PVST mode. 

Reference: http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/72836-rapidpvst-mig-config.html#upback1 


Q250. Which two options describe two functions of a neighbor solicitation message? (Choose two.) 

A. It requests the link-layer address of the target. 

B. It provides its own link-layer address to the target. 

C. It requests the site-local address of the target. 

D. It provides its own site-local address to the target. 

E. It requests the admin-local address of the target. 

F. It provides its own admin-local address to the target. 

Answer: A,B 

Explanation: 

Neighbor solicitation messages are sent on the local link when a node wants to determine the link-layer address of another node on the same local link (see the figure below). When a node wants to determine the link-layer address of another node, the source address in a neighbor solicitation message is the IPv6 address of the node sending the neighbor solicitation message. The destination address in the neighbor solicitation message is the solicited-node multicast address that corresponds to the IPv6 address of the destination node. The neighbor solicitation message also includes the link-layer address of the source node. 

Figure 1. IPv6 Neighbor Discovery: Neighbor Solicitation Message 

After receiving the neighbor solicitation message, the destination node replies by sending a neighbor advertisement message, which has a value of 136 in the Type field of the ICMP packet header, on the local link. The source address in the neighbor advertisement message is the IPv6 address of the node (more specifically, the IPv6 address of the node interface) sending the neighbor advertisement message. The destination address in the neighbor advertisement message is the IPv6 address of the node that sent the neighbor solicitation message. The data portion of the neighbor advertisement message includes the link-layer address of the node sending the neighbor advertisement message. After the source node receives the neighbor advertisement, the source node and destination node can communicate. 

Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6_basic/configuration/xe-3s/ip6b-xe-3s-book/ip6-neighb-disc-xe.html