Correct Answer: A

LFA Tie-Breaking Rules

When there are multiple candidate LFAs for a given primary path, EIGRP uses a tie-breaking rule to select one LFA per primary path per prefix. A tie-breaking rule considers LFAs that satisfy certain conditions or have certain attributes.

EIGRP uses the following four attributes to implement tie-breaking rules:

Interface-disjoint-Eliminates LFAs that share the outgoing interface with the protected path.

Linecard-disjoint-Eliminates LFAs that share the line card with the protected path.

Lowest-repair-path-metric-Eliminates LFAs whose metric to the protected prefix is high. Multiple LFAs with the same lowest path metric may remain in the routing table after this tie-breaker is applied.

- Shared Risk Link Group (SRLG)-disjoint-Eliminates LFAs that belong to any of the protected path SRLGs. SRLGs refer to situations where links in a network share a common fiber (or a common physical attribute). If one link fails, other links in the group may also fail. Therefore, links in a group share risks.

Source : https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_eigrp/configuration/xe-3s/asr1000/ire-xe-3s-asr1000/ire-ipfrr.html

Correct Answer: C

Correct Answer: A

Reference: https://www.cisco.com/c/en/us/td/docs/routers/7600/ios/15S/configuration/guide/7600_15_0s_book/ifindx.pdf

Correct Answer: C

The mapping was created through an NHRP registration request, as indicated by the flag setting registered. Next Hop Resolution Protocol (NHRP) can be used in place of static IP address to NBMA address mappings to allow the spoke

routers in an mGRE hub-and-spoke configuration to discover one another's physical IP addresses.

When the output of the show nhrp detail command shows the registered flag listed, it means that the mapping was created dynamically and was learned through a registration request to the next hop server (NHS).

The mapping was not created statically. Had it been created statically, the Type field would not be listed as dynamic. It would say static.

The NHRP information DID come from the next hop server (NHS). That is indicated by the presence of the authoritative flag. The NHS is the next hop to the destination as indicated by the routing table.

The device at 10.1.1.2 is not necessarily behind a NAT router. The presence of the nat flag in the output indicates that the device at 10.1.1.2 supports the NHRP NAT extension type for supporting dynamic spoke-to- spoke tunnels to or from

spokes behind a NAT router. This flag does not mean that the spoke (NHS client) is behind a NAT router.

Objective:

VPN Technologies

Sub-Objective:

Describe DMVPN (single hub)

References:

Home > Support > Product support > Cisco IOS and NX-OS software > Cisco IOS software releases 12.4 mainline > Configure > Feature Guides > NHRP

Correct Answer: C

The correct answer is area 1 default-cost 25. Even though another option (area 1 default 25) is a configurable abbreviation for the command, the more correct answer explicitly specifies the default-cost parameter. The correct syntax for the area default-cost command is shown below:

Router(config-router)# area area-id default-cost cost

If you have multiple border routers between two areas, you might prefer one exit-point router over the other for that area. By configuring one with a lower cost than the other, it will become the preferred exit point. If that router or its links were to fail, then the routers interior to the area would route through the second-best exit point. You could also set the default costs to values that are close to achieve better load balancing. The default default-cost is 1. Please see the network shown in the graphic.

Objective:

Layer 3 Technologies

Sub-Objective:

Configure and verify OSPF path preference

References:

Cisco IOS Master Command List, Release 12.4 > a through b > area default-cost