Which mechanism does External BGP use to prevent the formation of routing loops？（）A、AS pathB、Split horizonC、Poison reverseD、Unicast RPF check

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第3题：

Which of the following technologies can be used in distance vector routing protocols to prevent routing loops?（）

• A、Spanning Tree Protocol
• B、Shortest path first tree
• C、Link-state advertisements (LSA)
• D、Hold-down timers
• E、Split horizon
• F、VRP

正确答案:D,E

第4题：

Which BGP attribute is used by BGP to prevent routing loops?（）

• A、AS - path
• B、next - hop
• C、MED
• D、weight
• E、local preference
• F、origin

正确答案:A

第5题：

What is the purpose of the spanning-tree algorithm in a switched LAN?（）

• A、To provide a monitoring mechanism for networks in switched environments.
• B、To manage VLANs across multiple switches.
• C、To prevent switching loops in networks with redundant switched paths.
• D、To segment a network into multiple collision domains.
• E、To prevent routing loops in networks.

正确答案:C

第6题：

Within a BGP confederation how are routing loops avoided?（）

• A、split horizon
• B、the AS-path attribute
• C、the BGP cluster ID attribute
• D、the BGP originator ID attribute

正确答案:B

第7题：

Which mechanism does External BGP use to prevent the formation of routing loops?（）

• A、AS path
• B、Split horizon
• C、Poison reverse
• D、Unicast RPF check

正确答案:A

第8题：

Your MPLS implementation is currently using internal backdoor links. What can you do to minimize the impact of having these links？（）

• A、 use BGP as the CE-PE routing protocol
• B、 use OSPF as the CE-PE routing protocol
• C、 use EIGRP as the CE-PE routing protocol
• D、 use the SP to redistribute routes as external routes for OSPF and EIGRP
• E、 use route redistribution at each location to ensure external routes are imported into the IGP

正确答案:A

第9题：

Unicast Reverse Path Forwarding can perform all of these actions except which one？（）

• A、examine all packets received to make sure that the source addresses and source interfaces appear in the routing table and match the interfaces where the packets were received
• B、check to see if any packet received at a router interface arrives on the best return path
• C、combine with a configured ACL
• D、log its events，if you specify the logging options for the ACL entries used by the unicast rpf command
• E、inspect IP packets encapsulated in tunnels， such as GRE

正确答案:E

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第15题：

RIP version 2 is being used as the routing protocol within the Testking network.What does RIP version 2 use to prevent routing loops?（）

• A、CIDR
• B、Split horizon
• C、Authentication
• D、Classless masking
• E、Hold-down timers
• F、Multicast routing updates
• G、Path Vectoring

正确答案:B,E

第16题：

For which routes does LDP advertise a label binding？（）

• A、all routes in the routing table
• B、only the IGP and BGP routes in the routing table
• C、only the BGP routes in the routing table
• D、only the IGP routes in the routing table

正确答案:D

第17题：

Which configuration command allows the ERX Edge Router to perform Unicast Reverse Path Forwarding lookups on all packets received on an IP interface?（）

• A、ip sa-validate
• B、ip split-horizon
• C、ip access-routes
• D、ip filter-options

正确答案:A

第18题：

Which routing table stores IPv4 unicast routes and is used by multicast routing protocols to prevent loops?（）

• A、inet.0
• B、inet.1
• C、inet.2
• D、inet.3

正确答案:C

第19题：

In a switched LAN network, what is the Spanning-Tree algorithm used for?（）

• A、It is used to provide a mechanism for routing updates in switched environments.
• B、It is used to prevent routing loops in networks with redundant routes.
• C、It is used to prevent switching loops in networks with redundant switched routes.
• D、It is used to manage, the addition, deletion, and naming of VLANs across multiple switches.
• E、It is used to segment a network into multiple collision domains.
• F、None of the above.
• G、All of the above are functions of STP.

正确答案:C

第20题：

Which IOS features are used to avoid Routing loops when dynamic Routing protocols are used betweenPE and CE in MPLS-VPN networks？（）

• A、Site Of Origin SOO.
• B、SHAM links with OSPF
• C、BGP cost community
• D、BGP feature allow-as in
• E、RPF Reverse Path forwarding.
• F、Access-list Control in Distance Vector protocol like RIP and EIGRP.

正确答案:A,F

第21题：

Within a BGP confederation， how are routing loops avoided？（）

• A、Split horizon.
• B、AS confederation sequence.
• C、The BFP cluster ID attribute.
• D、The BGP originator ID attribute.

正确答案:B

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