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

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Q1. Refer to the exhibit. 

While reviewing a log file on a router with this NTP configuration, you note that the log entries of the router display a different time than the NTP time. 

Which action can you take to correct the problem? 

A. Add the localtime keyword to the service timestamps log datetime statement. 

B. Add the msec keyword to the service timestamps log datetime statement. 

C. Add the statement ntp broadcast to the NTP configuration of the neighboring router. 

D. Configure the router to be the NTP master. 

E. Remove the datetime keyword from the service timestamps log datetime statement. 

Answer:

Q2. DRAG DROP 

Drag and drop each STP port role on the left to the matching statement on the right. 

Answer:  

Q3. Which data plane protocol does EIGRP Over the Top use? 

A. MPLS 

B. GRE 

C. LISP 

D. IP-in-IP 

Answer:

Explanation: 

The EIGRP Over the Top solution can be used to ensure connectivity between disparate Enhanced Interior Gateway Routing Protocol (EIGRP) sites. This feature uses EIGRP on the control plane and Locator ID Separation Protocol (LISP) encapsulation on the data plane to route traffic across the underlying WAN architecture. EIGRP is used to distribute routes between customer edge (CE) devices within the network, and the traffic forwarded across the WAN architecture is LISP encapsulated. Therefore, to connect disparate EIGRP sites, you must configure the neighbor command with LISP encapsulation on every CE in the network. 

Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_eigrp/configuration/xe-3s/ire-xe-3s-book/ire-eigrp-over-the-top.html 

Q4. Which two statements about OSPFv3 are true? (Choose two.) 

A. It supports unicast address families for IPv4 and IPv6. 

B. It supports unicast address families for IPv6 only. 

C. It supports only one address family per instance. 

D. It supports the use of a cluster ID for loop prevention. 

E. It supports multicast address families for IPv4 and IPv6. 

F. It supports multicast address families for IPv6 only. 

Answer: A,C 

Q5. Which action does route poisoning take that serves as a loop-prevention method? 

A. It immediately sends routing updates with an unreachable metric to all devices. 

B. It immediately sends routing updates with a metric of 255 to all devices. 

C. It prohibits a router from advertising back onto the interface from which it was learned. 

D. It advertises a route with an unreachable metric back onto the interface from which it was learned. 

E. It poisons the route by tagging it uniquely within the network. 

Answer:

Explanation: 

With route poisoning, when a router detects that one of its connected routes has failed, the router will poison the route by assigning an infinite metric to it and advertising it to neighbors. 

Q6. Which two statements about IBGP multipath are true? (Choose two.) 

A. The IGP metric of the BGP next hop can be different from the best-path IGP metric if you configure the router for unequal-cost IBGP multipath. 

B. The IGP metric of the BGP next hop must be the same as the best-path IGP metric. 

C. The equivalent next-hop-self is performed on the best path from among the IBGP multipaths before it is forwarded to external peers. 

D. The path should be learned from an external neighbor. 

E. The router BGP process must learn the path from a confederation-external or external neighbor. 

F. The router BGP process must learn the path from an internal neighbor. 

Answer: A,F 

Q7. Refer to the exhibit. 

Which IP packets will be accepted from EBGP neighbor 10.1.1.1? 

A. IP packets with a TTL count in the header that is equal to or greater than 253 

B. IP packets with a TTL count in the header that is equal to 253 

C. IP packets with a TTL count in the header that is equal to or greater than 2 

D. IP packets with a TTL count in the header that is equal to 2 

Answer:

Explanation: 

neighbor ip-address ttl-security hops hop-count 

ExamplE. 

Router(config-router)# neighbor 10.1.1.1 ttl-security hops 2 

Configures the maximum number of hops that separate two peers. 

. The hop-count argument is set to number of hops that separate the local and remote peer. 

If the expected TTL value in the IP packet header is 254, then the number 1 should be configured for the hop-count argument. The range of values is a number from 1 to 254. 

. When this feature is enabled, BGP will accept incoming IP packets with a TTL value that is 

equal to or greater than the expected TTL value. Packets that are not accepted are silently discarded. 

. The example configuration sets the expected incoming TTL value to at least 253, which is 255 minus the TTL value of 2, and this is the minimum TTL value expected from the BGP peer. The local router will accept the peering session from the 10.1.1.1 neighbor only if it is 1 or 2 hops away. 

Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_2s/feature/guide/fs_btsh.html 

Q8. Refer to the exhibit. 

You have just created a new VRF on PE3. You have enabled debug ip bgp vpnv4 unicast updates on PE1, and you can see the route in the debug, but not in the BGP VPNv4 table. 

Which two statements are true? (Choose two.) 

A. VPNv4 is not configured between PE1 and PE3. 

B. address-family ipv4 vrf is not configured on PE3. 

C. After you configure route-target import 999:999 for a VRF on PE3, the route will be accepted. 

D. PE1 will reject the route due to automatic route filtering. 

E. After you configure route-target import 999:999 for a VRF on PE1, the route will be accepted. 

Answer: D,E 

Explanation: 

The route target extended community for VPLS auto-discovery defines the import and export policies that a VPLS instance uses. The export route target sets an extended community attribute number that is appended to all routes that are exported from the VPLS instance. The import route target value sets a filter that determines the routes that are accepted into the VPLS instance. Any route with a value in its import route target contained in its extended attributes field matching the value in the VPLS instance’s import route target are accepted. Otherwise the route is rejected. 

Q9. Which three values can be used to tag external EIGRP routes? (Choose three.) 

A. The router ID of the router that redistributed the route 

B. The administrative distance of the external protocol 

C. The protocol ID of the external protocol 

D. The cost to reach the router that redistributed the route 

E. The metric from the external protocol F. The router ID of the router from which the external protocol route was learned 

Answer: A,C,E 

Explanation: 

EIGRP has the notion of internal and external routes. Internal routes are ones that have been originated within an EIGRP autonomous system (AS). Therefore, a directly attached network that is configured to run EIGRP is considered an internal route and is propagated with this information throughout the EIGRP AS. External routes are ones that have been learned by another routing protocol or reside in the routing table as static routes. These routes are tagged individually with the identity of their origination. External routes are tagged with the following information: 

The router ID of the EIGRP router that redistributed the route. 

The AS number where the destination resides. 

A configurable administrator tag. 

Protocol ID of the external protocol. 

The metric from the external protocol. 

Bit flags for default routing. 

Reference: http://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/13669-1.html#route_tagging 

Q10. Which technology can be affected when switches are used that do not support jumbo frames? 

A. 802.1x 

B. BFD 

C. OSPFv3 

D. 802.1q 

Answer:

Explanation: 

The 802.1Q tag is 4 bytes. Therefore, the resulting Ethernet frame can be as large as 1522 bytes. If jumbo frames are not supported, then typically the MTU on an Ethernet link needs to be lowered to 1496 to support this extra 802.1Q tag.