Q1. Refer to the exhibit.
Which two statements are true? (Choose two.)
A. This is the output of the show ip ospf command.
B. This is the output of the show ip protocols command.
C. This router is an ABR.
D. This router is an ASBR.
E. Authentication is not configured for the area.
Answer: A,E
Explanation:
The following is sample output from the show ip ospf command when entered without a specific OSPF process ID with no authentication.
Router# show ip ospf
Routing Process "ospf 201" with ID 10.0.0.1 and Domain ID 10.20.0.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
LSA group pacing timer 100 secs
Interface flood pacing timer 55 msecs
Retransmission pacing timer 100 msecs
Number of external LSA 0. Checksum Sum 0x0
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 2. 2 normal 0 stub 0 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 2
Area has no authentication
SPF algorithm executed 4 times
Area ranges are
Number of LSA 4. Checksum Sum 0x29BEB
Number of opaque link LSA 0. Checksum Sum 0x0
Number of DCbitless LSA 3 Number of indication LSA 0
Number of DoNotAge LSA 0 Flood list length 0
Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_ospf/command/iro-cr-book/ospf-s1.html#wp8749965360
Q2. Refer to the exhibit.
Which feature can R1 use to fail over from R2 to R3 if the address for R2 becomes unavailable?
A. object tracking
B. HSRP
C. GLBP
D. LACP
Answer: A
Explanation:
The object tracking feature allows you to create a tracked object that multiple clients can use to modify the client behavior when a tracked object changes. Several clients register their interest with the tracking process, track the same object, and take different actions when the object state changes.
Clients include the following features:
. Embedded Event Manager (EEM)
. Gateway Load Balancing Protocol (GLBP)
. Hot Standby Redundancy Protocol (HSRP)
. Virtual port channel (vPC)
. Virtual Router Redundancy Protocol (VRRP)
The object tracking monitors the status of the tracked objects and communicates any changes made to interested clients. Each tracked object is identified by a unique number that clients can use to configure the action to take when a tracked object changes state.
Reference: http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/5_x/nx-os/unicast/configuration/guide/l3_cli_nxos/l3_object.html
Q3. Which algorithm heavily influenced the algorithm used by path-vector protocols?
A. Bellman-Ford
B. SPF
C. DUAL
D. Spanning-Tree
E. Adaptive
F. Deflection
Answer: A
Explanation:
A path vector protocol is a computer network routing protocol which maintains the path information that gets updated dynamically. Updates which have looped through the network and returned to the same node are easily detected and discarded. This algorithm is sometimes used in Bellman–Ford routing algorithms to avoid "Count to Infinity" problems.
Reference: http://en.wikipedia.org/wiki/Path_vector_protocol
Q4. Which statement about the NHRP network ID is true?
A. It is sent from the spoke to the hub to identify the spoke as a member of the same NHRP domain.
B. It is sent from the hub to the spoke to identify the hub as a member of the same NHRP domain.
C. It is sent between spokes to identify the spokes as members of the same NHRP domain.
D. It is a locally significant ID used to define the NHRP domain for an interface.
Answer: D
Explanation:
The NHRP network ID is used to define the NHRP domain for an NHRP interface and differentiate between multiple NHRP domains or networks, when two or more NHRP domains (GRE tunnel interfaces) are available on the same NHRP node (router). The NHRP network ID is used to help keep two NHRP networks (clouds) separate from each other when both are configured on the same router. The NHRP network ID is a local only parameter. It is significant only to the local router and it is not transmitted in NHRP packets to other NHRP nodes. For this reason the actual value of the NHRP network ID configured on a router need not match the same NHRP network ID on another router where both of these routers are in the same NHRP domain. As NHRP packets arrive on a GRE interface, they are assigned to the local NHRP domain in the NHRP network ID that is configured on that interface.
Reference:
http://www.cisco.com/c/en/us/td/docs/ios/12_4/ip_addr/configuration/guide/hadnhrp.html
Q5. DRAG DROP
Drag and drop the TACACS+ configuration command on the left to the correct function it performs on the right.
Answer:
Q6. Which three capabilities are provided by MLD snooping? (Choose three.)
A. dynamic port learning
B. IPv6 multicast router discovery
C. user-configured ports age out automatically
D. a 5-minute aging timer
E. flooding control packets to the egress VLAN
F. a 60-second aging timer
Answer: A,B,D
Explanation:
Like IGMP snooping, MLD snooping performs multicast router discovery, with these characteristics:
. Ports configured by a user never age out.
. Dynamic port learning results from MLDv1 snooping queries and IPv6 PIMv2 packets.
. If there are multiple routers on the same Layer 2 interface, MLD snooping tracks a single multicast router on the port (the router that most recently sent a router control packet).
. Dynamic multicast router port aging is based on a default timer of 5 minutes; the multicast router is deleted from the router port list if no control packet is received on the port for 5 minutes.
. IPv6 multicast router discovery only takes place when MLD snooping is enabled on the switch.
Reference: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_55_se/configuration/guide/scg3750/swv6mld.pdf
Q7. Which three statements about EIGRP wide metrics are true? (Choose three.)
A. The maximum metric is 65536.
B. The default delay is 1,000,000 picoseconds.
C. They allow up to 100 hops.
D. They allow up to 256 hops.
E. The default delay is 1,000,000 milliseconds.
F. The maximum metric is 51200.
Answer: A,B,C
Q8. Which two technologies are supported by EIGRP? (Choose two.)
A. clear-text authentication
B. MD5 authentication
C. stub routing
D. multiple areas
Answer: B,C
Explanation:
The IP Enhanced IGRP Route Authentication feature provides MD5 authentication of routing updates from the EIGRP routing protocol. The MD5 keyed digest in each EIGRP packet prevents the introduction of unauthorized or false routing messages from unapproved sources. The EIGRP stub routing feature improves network stability, reduces resource utilization, and simplifies the stub device configuration. Stub routing is commonly used in hub-and-spoke network topologies. In a hub-and-spoke network, one or more end (stub) networks are connected to a remote device (the spoke) that is connected to one or more distribution devices (the hub). The remote device is adjacent to one or more distribution devices. The only route for IP traffic to reach the remote device is through a distribution device.
References: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_eigrp/configuration/15-s/ire-15-s-book/ire-rte-auth.html http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_eigrp/configuration/15-s/ire-15-s-book/ire-eigrp-stub-rtg.html
Q9. Which two functions are performed by the DR in OSPF? (Choose two.)
A. The DR originates the network LSA on behalf of the network.
B. The DR is responsible for the flooding throughout one OSPF area.
C. The DR forms adjacencies with all other OSPF routers on the network, in order to synchronize the LSDB across the adjacencies.
D. The DR is responsible for originating the type 4 LSAs into one area.
Answer: A,C
Explanation:
The DR originates the network LSA (LSA Type 2) which lists all the routers on the segment it is adjacent to -> A is correct. Types 2 are ooded within its area only; does not cross ABR -> B is incorrect. The broadcast and non-broadcast network types elect a DR/BDR. They form adjacencies to all other OSPF routers on the network and help synchronize the Link State Database (LSDB) across the adjacencies -> C is correct. LSAs Type 4 are originated by the ABR to describe an ASBR to routers in other areas so that routers in other areas know how to get to external routes through that ASBR -> D is incorrect.
Q10. DRAG DROP
Drag each AF class on the left to its matching DSCP binary value on the right.
Answer:
Q11. Which two statements about device access control are true? (Choose two.)
A. The AUX port is displayed as type tty in the output of the show line command.
B. VTY lines are associated with physical interfaces on a network device.
C. MPP restricts device-management access to interfaces that are configured under the control plane host configuration.
D. The enable password command sets an MD5 one-way encrypted password.
E. The console port supports hardware flow control
Answer: C,E
Q12. Which two statements are true about a 6to4 tunnel connecting two IPv6 islands over the IPv4 Internet? (Choose two.)
A. It embeds the IPv6 packet into the IPv4 payload with the protocol type set to 51.
B. It works by appending the private IPv4 address (converted into hexadecimal format) to the 2002::/16 prefix.
C. It embeds the IPv6 packet into the IPv4 payload with the protocol type set to 41.
D. It works by appending the public IPv4 address (converted into hexadecimal format) to the 2002::/16 prefix.
Answer: C,D
Explanation:
6to4 embeds an IPv6 packet in the payload portion of an IPv4 packet with protocol type 41. To send an IPv6 packet over an IPv4 network to a 6to4 destination address, an IPv4
header with protocol type 41 is prepended to the IPv6 packet. The IPv4 destination address for the prepended packet header is derived from the IPv6 destination address of the inner packet (which is in the format of a 6to4 address), by extracting the 32 bits immediately following the IPv6 destination address's 2002::/16 prefix. The IPv4 source address in the prepended packet header is the IPv4 address of the host or router which is sending the packet over IPv4. The resulting IPv4 packet is then routed to its IPv4 destination address just like any other IPv4 packet.
Reference: http://en.wikipedia.org/wiki/6to4
Q13. A GRE tunnel is down with the error message %TUN-5-RECURDOWN: Tunnel0 temporarily disabled due to recursive routing error.
Which two options describe possible causes of the error? (Choose two.)
A. Incorrect destination IP addresses are configured on the tunnel.
B. There is link flapping on the tunnel.
C. There is instability in the network due to route flapping.
D. The tunnel mode and tunnel IP address are misconfigured.
E. The tunnel destination is being routed out of the tunnel interface.
Answer: C,E
Explanation:
The %TUN-5-RECURDOWN: Tunnel0 temporarily disabled due to recursive routing error message means that the generic routing encapsulation (GRE) tunnel router has discovered a recursive routing problem. This condition is usually due to one of these causes:
. A misconfiguration that causes the router to try to route to the tunnel destination address using the tunnel interface itself (recursive routing)
. A temporary instability caused by route flapping elsewhere in the network
Reference: http://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/22327-gre-flap.html
Q14. Which congestion-avoidance or congestion-management technique can cause global synchronization?
A. Tail drop
B. Random early detection
C. Weighted random early detection
D. Weighted fair queuing
Answer: A
Explanation:
Tail Drop
Tail drop treats all traffic equally and does not differentiate between classes of service. Queues fill during periods of congestion. When the output queue is full and tail drop is in effect, packets are dropped until the congestion is eliminated and the queue is no longer full.
Weighted Random Early Detection
WRED avoids the globalization problems that occur when tail drop is used as the congestion avoidance mechanism on the router. Global synchronization occurs as waves of congestion crest only to be followed by troughs during which the transmission link is not fully utilized. Global synchronization of TCP hosts, for example, can occur because packets are dropped all at once. Global synchronization manifests when multiple TCP hosts reduce their transmission rates in response to packet dropping, then increase their transmission rates once again when the congestion is reduced.
Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_2/qos/configuration/guide/fqos_c/qcfconav.ht ml#wp1002048
Q15. Which command sets the maximum segment size for a TCP packet initiated from a router?
A. ip mtu
B. ip tcp adjust-mss
C. ip tcp mss
D. ip tcp window-size
Answer: C