Q1. DRAG DROP
Drag each statement about EtherChannel protocols on the left to the matching EtherChannel protocol on the right.
Answer:
Q2. Refer to the exhibit.
IPv6 SLAAC clients that are connected to the router are unable to acquire IPv6 addresses. What is the reason for this issue?
A. Router advertisements are not sent by the router.
B. Duplicate address detection is disabled but is required on multiaccess networks.
C. The interface is configured to support DHCPv6 clients only.
D. The configured interface MTU is too low for IPv6 to be operational.
Answer: A
Q3. DRAG DROP
Drag and drop each step of the Unicast RPF process on the left into the correct order on the right.
Answer:
Q4. DRAG DROP
Drag and drop each description of IPv6 transition technology on the left to the matching IPv6 transition technology category on the right.
Answer:
Q5. Which configuration sets a minimum quality of service on a Layer 2 access switch?
A. mls qos cos override
mls qos cos 2
B. mls qos cos 2
C. mls qos trust cos
mls qos cos 2
D. mls qos trust cos
E. mls qos trust dscp
Answer: A
Explanation:
The mls qos cos override interface command must be used to ensure that untrusted CoS values are explicitly set 0 (default).
Reference: http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/Qo S-SRND-Book/QoSDesign.html
Q6. What is the function of an EIGRP sequence TLV packet?
A. to acknowledge a set of sequence numbers during the startup update process
B. to list the peers that should listen to the next multicast packet during the reliable multicast process
C. to list the peers that should not listen to the next multicast packet during the reliable multicast process
D. to define the initial sequence number when bringing up a new peer
Answer: C
Explanation:
EIGRP sends updates and other information between routers using multicast packets to 224.0.0.10. For example in the topology below, R1 made a change in the topology and it needs to send updates to R2 & R3. It sends multicast packets to EIGRP multicast address 224.0.0.10. Both R2 & R3 can receive the updates and acknowledge back to R1 using unicast. Simple, right? But what if R1 sends out updates, only R2 replies but R3 never does? In the case a router sends out a multicast packet that must be reliable delivered (like in this case), an EIGRP process will wait until the RTO (retransmission timeout) period has passed before beginning a recovery action. This period is calculated from the SRTT (smooth round-trip time). After R1 sends out updates it will wait for this period to expire. Then it makes a list of all the neighbors from which it did not receive an Acknowledgement (ACK). Next it sends out a packet telling these routers stop listening to multicast until they are been notified that it is safe again. Finally the router will begin sending unicast packets with the information to the routers that didn’t answer, continuing until they are caught up. In our example the process will be like this:
1. R1 sends out updates to 224.0.0.10
2. R2 responds but R3 does not
3. R1 waits for the RTO period to expire
4. R1 then sends out an unreliable-multicast packet, called a sequence TLV (Type-Length-Value) packet, which tells R3 not to listen to multicast packets any more
5. R1 continues sending any other muticast traffic it has and delivering all traffic, using unicast to R3, until it acknowledges all the packets
6. Once R3 has caught up, R1 will send another sequence TLV, telling R3 to begin listening to multicast again. The sequence TLV packet contains a list of the nodes that should not listen to multicast packets while the recovery takes place. But notice that the TLV packet in step 6 does not contain any nodes in the list.
Note. In the case R3 still does not reply in step 4, R1 will attempt to retransmit the unicast 16 times or continue to retransmit until the hold time for the neighbor in question expires. After this time, R1 will declare a retransmission limit exceeded error and will reset the neighbor.
(Reference: EIGRP for IP: Basic Operation and Configuration)
Q7. Which timer expiration can lead to an EIGRP route becoming stuck in active?
A. hello
B. active
C. query
D. hold
Answer: B
Explanation:
As noted above, when a route goes into the active state, the router queries its neighbors to find a path to the pertinent network. At this point, the router starts a three minute active timer by which time it must receive replies from all queried neighbors. If a neighbor has feasible successors for the route, it will recalculate its own local distance to the network and report this back. However, if a neighbor does not have a feasible successor, it also goes into active state. In some cases, multiple routers along multiple query paths will go into active state as routers continue to query for the desired route. In most cases, this process will yield responses from all queried routers and the sought after route will transition back into the passive state within the three minute SIA query timer. In the case that none of the queried routers can provide a feasible successor, the route is cleared. In some cases, a response is not received between two neighbor routers because of link failures, congestion or some other adverse condition in either the network or on the queried router, and the three minute active timer expires on the router originating the query. When this happens, the querying router that did not receive a response logs a “DUAL-3-SIA” or “stuck-in-active” error for the route and then drops and restarts its adjacency with the non-responding router
Reference: http://www.packetdesign.com/resources/technical-briefs/diagnosing-eigrp-stuck-active
Q8. Which two statements about the assert process in LAN-based PIM are true? (Choose two.)
A. If the metrics are the same, the router with the lowest advertised routing protocol metric for that route is elected.
B. If the metrics are the same, the router with the highest IP address on the LAN is elected.
C. If the metrics are the same, the router with the highest advertised routing protocol metric for that route is elected.
D. If the metrics are the same, the router with the lowest IP address on the LAN is elected.
Answer: A,B
Q9. Refer to the exhibit.
At which location will the benefit of this configuration be observed?
A. on Router A and its upstream routers B. on Router A and its downstream routers
C. on Router A only
D. on Router A and all of its ARP neighbors
Answer: B
Explanation:
The following example shows how to configure the router (and downstream routers) to drop all options packets that enter the network: Router(config)# ip options drop
Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/sel_drop.html
Q10. Refer to the exhibit.
Which configuration must you apply to router R2 to enable BFD?
A)
B)
C)
D)
A. Exhibit A
B. Exhibit B
C. Exhibit C
D. Exhibit D
Answer: A