Q1. On a broadcast interface, which two OSPF states support BFD sessions? (Choose two.)
A. DR
B. BDR
C. DROTHER
D. 2WAY
E. FULL
F. ACTIVE
Answer: A,B
Q2. Refer to the exhibit.
Which two statements about the R1 configuration are true? (Choose two.)
A. The IP TTL value is copied to the MPLS field during label imposition.
B. The structure of the MLPS network is hidden in a traceroute.
C. The LDP session interval and hold times are configured for directly connected neighbors.
D. R1 protects the session for 86400 seconds.
E. All locally assigned labels are discarded.
Answer: B,D
Q3. Which IP SLA operation type uses IP to measure the round-trip time between a router and a device?
A. HTTP
B. ICMP Echo
C. ICMP Path Jitter
D. UDP Jitter for VoIP
Answer: B
Q4. Which option describes the purpose of the leak-map keyword in the command eigrp stub connected leak-map EigrpLeak?
A. It allows the specified static routes to be advertised.
B. It allows exceptions to the route summarization that is configured.
C. It allows specified EIGRP-learned routes to be advertised.
D. It restricts specified connected routes from being advertised.
Answer: C
Explanation:
ExamplE. eigrp stub leak-map Command
In the following example, the eigrp stub command is issued with the leak-map name keyword-argument pair to configure the device to reference a leak map that identifies routes to be advertised that would have been suppressed otherwisE.
Device(config)# router eigrp 1
Device(config-router)# network 10.0.0.0
Device(config-router)# eigrp stub leak-map map1
Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_eigrp/configuration/15-mt/ire-15-mt-book/ire-eigrp-stub-rtg.html#GUID-FB899CA9-E9DE-48D8-8048-C971179E4E24
Q5. Which two statements about NPTv6 are true? (Choose two.)
A. The translation is invisible to applications that hard code IP information within the application logic.
B. It is a one-way stateful translation for the IPv6 address.
C. Translation is 1:1 at the network layer.
D. It is a two-way stateless translation for the network prefix.
Answer: C,D
Explanation:
This document describes a stateless, transport-agnostic IPv6-to-IPv6 Network Prefix Translation (NPTv6) function that provides the address-independence benefit associated with IPv4-to-IPv4 NAT (NAPT44) and provides a 1:1 relationship between addresses in the "inside" and "outside" prefixes, preserving end-to-end reachability at the network layer NPTv6 Translation is stateless, so a "reset" or brief outage of an NPTv6 Translator does not break connections that traverse the translation function, and if multiple NPTv6 Translators exist between the same two networks, the load can shift or be dynamically load shared among them. NPTv6 is defined to include a two-way, checksum-neutral, algorithmic translation function, and nothing else.
Reference: https://tools.ietf.org/html/rfc6296
Q6. What are two advantages to using Asynchronous mode instead of Demand mode for BFD? (Choose two.)
A. Asynchronous mode requires half as many packets as Demand mode for failure detection.
B. Asynchronous mode can be used in place of the echo function.
C. Asynchronous mode supports a larger number of BFD sessions.
D. Asynchronous mode requires one fourth as many packets as Demand mode for failure detection.
E. Asynchronous mode’s round-trip jitter is less than that of Demand mode.
Answer: A,B
Explanation:
Pure Asynchronous mode is advantageous in that it requires half as many packets to achieve a particular Detection Time as does the Echo function. It is also used when the Echo function cannot be supported for some reason.
Reference: https://tools.ietf.org/html/rfc5880
Q7. Which two statements about MLD are true? (Choose two.)
A. MLD is a subprotocol of ICMPv6.
B. When a single link supports multiple interfaces, only one interface is required to send MLD messages.
C. MLD is a subprotocol of PIMv6.
D. When a single link supports multiple interfaces, all supported interfaces are required to send MLD messages.
E. There are three subtypes of MLD query messages.
F. The code section in the MLD message is set to 1 by the sender and ignored by receivers.
Answer: A,B
Q8. Which two options are ways in which an OSPFv3 router handles hello packets with a clear address-family bit? (Choose two.)
A. IPv4 unicast packets are discarded.
B. IPv6 unicast packets are discarded.
C. IPv4 unicast packets are forwarded.
D. IPv6 unicast packets are forwarded.
Answer: A,D
Explanation:
A typical distance vector protocol saves the following information when computing the best path to a destination: the distance (total metric or distance, such as hop count) and the vector (the next hop). For instance, all the routers in the network in Figure 1 are running Routing Information Protocol (RIP). Router Two chooses the path to Network A by examining the hop count through each available path.
Since the path through Router Three is three hops, and the path through Router One is two hops, Router Two chooses the path through One and discards the information it learned through Three. If the path between Router One and Network A goes down, Router Two loses all connectivity with this destination until it times out the route of its routing table (three update periods, or 90 seconds), and Router Three re-advertises the route (which occurs every 30 seconds in RIP). Not including any hold-down time, it will take between 90 and 120 seconds for Router Two to switch the path from Router One to Router Three. EIGRP, instead of counting on full periodic updates to re-converge, builds a topology table from each of its neighbor's advertisements (rather than discarding the data), and converges by either looking for a likely loop-free route in the topology table, or, if it knows of no other route, by querying its neighbors. Router Two saves the information it received from both Routers One and Three. It chooses the path through One as its best path (the successor) and the path through Three as a loop-free path (a feasible successor). When the path through Router One becomes unavailable, Router Two examines its topology table and, finding a feasible successor, begins using the path through Three immediately.
Reference: http://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/16406-eigrp-toc.html
Q9. Which statement about the function of poison reverse in EIGRP is true?
A. It tells peers to remove paths that previously might have pointed to this router.
B. It tells peers to remove paths to save memory and bandwidth.
C. It provides reverse path information for multicast routing.
D. It tells peers that a prefix is no longer reachable.
Answer: A
Explanation:
Poison Reverse in EIGRP states: “Once you learn of a route through an interface, advertise it as unreachable back through that same interface”. For more information please read here. http://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/16406-eigrp-toc.html#splithorizon.
Q10. 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