400-101 Exam - CCIE Routing and Switching (v5.0)

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Q1. Which three statements about IPsec VTIs are true? (Choose three.) 

A. IPsec sessions require static mapping to a physical interface. 

B. They can send and receive multicast traffic. 

C. They can send and receive traffic over multiple paths. 

D. They support IP routing and ACLs. 

E. They can send and receive unicast traffic. 

F. They support stateful failover. 

Answer: B,D,E 

Q2. Which three statements describe the characteristics of a VPLS architecture? (Choose three.) 

A. It forwards Ethernet frames. 

B. It maps MAC address destinations to IP next hops. 

C. It supports MAC address aging. 

D. It replicates broadcast and multicast frames to multiple ports. 

E. It conveys MAC address reachability information in a separate control protocol. 

F. It can suppress the flooding of traffic. 

Answer: A,C,D 

Explanation: 

As a VPLS forwards Ethernet frames at Layer 2, the operation of VPLS is exactly the same as that found within IEEE 802.1 bridges in that VPLS will self learn source MAC address to port associations, and frames are forwarded based upon the destination MAC address. Like other 802.1 bridges, MAC address aging is supported. 

Reference: http://www.cisco.com/en/US/products/hw/routers/ps368/products_white_paper09186a0080 1f6084.shtml 

Q3. Which three features require Cisco Express Forwarding? (Choose three.) 

A. NBAR 

B. AutoQoS 

C. fragmentation 

D. MPLS 

E. UplinkFast 

F. BackboneFast 

Answer: A,B,D 

Explanation: 

QoS Features That Require CEF 

These class-based QoS features are supported only on routers that run CEF. 

.Network Based Application Recognition (NBAR) provides intelligent network classification. For more information, refer to Network Based Application Recognition. 

. The AutoQoS -VoIP feature simplifies and speeds up the implementation and provisioning of QoS for VoIP traffic. This feature is enabled with the help of the auto qos voip command. CEF must be enabled at the interface or ATM PVC before the auto qos command can be used. For more information about this feature and its prerequisites, refer to AutoQoS -VoIP. 

From MPLS Fundamentals - Luc De Ghein 

Why Is CEF Needed in MPLS Networks? 

Concerning MPLS, CEF is special for a certain reason; otherwise, this book would not explicitly cover it. Labeled packets that enter the router are switched according to the label forwarding information base (LFIB) on the router. IP packets that enter the router are switched according to the CEF table on the router. Regardless of whether the packet is switched according to the LFIB or the CEF table, the outgoing packet can be a labeled packet or an IP packet 

Reference: http://www.cisco.com/c/en/us/support/docs/asynchronous-transfer-mode-atm/ip-to-atm-class-of-service/4800-cefreq.html 

Q4. In the DiffServ model, which class represents the lowest priority with the highest drop probability? 

A. AF11 

B. AF13 

C. AF41 

D. AF43 

Answer:

Explanation: 

Assured Forwarding (AF) Behavior Group 

Class 1 

Class 2 

Class 3 

Class 4 

Low Drop 

AF11 (DSCP 10) 

AF21 (DSCP 18) 

AF31 (DSCP 26) 

AF41 (DSCP 34) 

Med Drop 

AF12 (DSCP 12) 

AF22 (DSCP 20) 

AF32 (DSCP 28) 

AF42 (DSCP 36) 

High Drop 

AF13 (DSCP 14) 

AF23 (DSCP 22) 

AF33 (DSCP 30) 

AF43 (DSCP 38) 

Reference: http://en.wikipedia.org/wiki/Differentiated_services 

Q5. DRAG DROP 

Drag and drop the StackWise stack master election rule on the left into the correct priority order on the right. 

Answer:  

Q6. Which mechanism can be used on Layer 2 switches so that only multicast packets with downstream receivers are sent on the multicast router-connected ports? 

A. IGMP snooping 

B. Router Guard 

C. PIM snooping 

D. multicast filtering 

Answer:

Explanation: 

Ideally, the Layer 2 device should forward the multicast transmission only out ports to which receivers are connected and also out any ports that are connected to downstream multicast routers. This configuration requires a Layer 2 device to be able to determine the ports on which multicast routers and receivers for each separate (S,G) or (*,G) multicast group are located. To facilitate intelligent forwarding of multicast traffic on the LAN, Cisco Catalyst switches support two mechanisms: 

. IGMP snooping — The switch listens in or "snoops" IGMP communications between receivers and multicast routers. This snooping enables the switch to determine which ports are connected to receivers for each multicast group and which ports are connected to multicast routers. 

. Cisco Group Management Protocol (CGMP) — The switch communicates with multicasts routers, with multicast routers relaying group membership information to switches. 

Reference: https://www.informit.com/library/content.aspx?b=CCNP_Studies_Switching&seqNum=59 

Q7. Refer to the exhibit. 

Routers R1, R2, and R3 are configured as shown, and traffic from R2 fails to reach 172.29.168.3. 

Which action can you take to correct the problem? 

A. Correct the static route on R1. 

B. Correct the default route on R2. 

C. Edit the EIGRP configuration of R3 to enable auto-summary. 

D. Correct the network statement for 172.29.168.3 on R3. 

Answer:

Explanation: 

On R1 we see there is a wrongly configured static route: ip route 172.29.168.3 255.255.255.255 172.17.17.2. It should be ip route 172.29.168.3 255.255.255.255 10.17.12.3. 

Q8. DRAG DROP 

Drag and drop the NetFlow Export feature on the left to the NetFlow version that first supported it on the right. 

Answer:  

Q9. Which two statements about IPv4 and IPv6 networks are true? (Choose two.) 

A. In IPv6, hosts perform fragmentation. 

B. IPv6 uses a UDP checksum to verify packet integrity. 

C. In IPv6, routers perform fragmentation. 

D. In IPv4, fragmentation is performed by the source of the packet. 

E. IPv4 uses an optional checksum at the transport layer. 

F. IPv6 uses a required checksum at the network layer. 

Answer: A,B 

Q10. 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: