When verifying OSPF virtual link problems, which is an important item to check on the two transit OSPF routers?()A. OSPF process IDB. OSPF router IDC. OSPF network typeD. OSPF memory usageE. OSPF CPU utilizationF. OSPF stub area configurations

第1题：

第2题：

Which two features prevent routing loops between the OSPF sites of a customer when the sites aremultihomed or a backdoor link is used between the sites？ （）

• A、sham link
• B、down bit
• C、virtual link
• D、Site of Origin
• E、domain tag

第3题：

When verifying OSPF virtual link problems, which is an important item to check on the two transit OSPF routers?（）

• A、OSPF process ID
• B、OSPF router ID
• C、OSPF network type
• D、OSPF memory usage
• E、OSPF CPU utilization
• F、OSPF stub area configurations

第4题：

Several links have been broken so th at for the next day or two, what was formerly a contiguous area 0 has been broken into two parts. However, both parts of area 0 have working links into area 1 using routers with RID 1.1.1.1 and 2.2.2.2. Which answers list the command on the router with RID 1.1.1.1 to create a virtual link to help solve this temporary problem?（）

• A、area 0 virtual - link 2.2.2.2
• B、area 1 virtual - link 2.2.2.2
• C、area 0 source - rid 1.1.1.1 dest - rid 2.2.2.2
• D、virtual - link transit - area 1 RID 2.2.2.2

第5题：

You have completed an OSPF implementation, and you are verifying OSPF operation. During this verification, you notice that the OSPF route of 172.16.10.0 is repeatedly appearing and disappearing from the routing table. Further investigation finds that the OSPF CPU utilization is very high and the routers are constantly performing SPF calculations. You determine that 172.16.20.2 is the source of the 172.16.10.0 route. Using the show ip ospf database router 172.16.20.1 command, you notice that when this show command is performed repeatedly, the contents of the LSA change every few seconds. What could be the cause of this problem?（）

• A、OSPF authentication errors between some of the routers
• B、Two routers have the same OSPF router ID
• C、Issues with mistuned OSPF timers
• D、OSPF LSA pacing issues between some of the routers
• E、OSPF neighbor adjacency problems between some of the routers

第6题：

You are running OSPF between two ERX Edge Routers across an OC-12c link with HDLC encapsulation. How many designated routers are present for this link?（）

• A、0
• B、1
• C、2
• D、3

第7题：

What is the correct virtual link configuration on an OSPF router？（）

• A、area 0.0.0.0{ linkneighbor-id 172.168.18.2 transit-area 0.0.2.1；}
• B、area 0.0.0.0{ virtual-linkneighbor-id 172.168.18.2 transit-area 0.0.2.1；}
• C、area 0.0.0.1{ virtual-linkneighbor-id 172.168.18.2 transit-area 0.0.2.1；}
• D、area 0.0.2.1{ virtual-linkneighbor-id 172.168.18.2 transit-area 0.0.0.0；}

第8题：

Which routers must be configured with the same authentication string when configuring OSPF authentication？（）

• A、all routers on a link
• B、all routers in an area
• C、all external OSPF peers
• D、all routers in an OSPF domain

第9题：

Routers A and B have an OC12c and a GE link between them and are running OSPF over both ofthese links. Which statement is correct, assuming the default JUNOS software OSPF metric calculation?（）

• A、There are two equal cost paths between a and b.
• B、The ge link is the preferred path between a and b.
• C、The oc12c link is the preferred path between a and b.
• D、Manual metric assignment must be configured to determine the outcome

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第13题：

If the OSPF protocol is used to connect customer edge （CE） routers to service provider edge（PE） routers in the VPN backbone， which two options best describe the use of SHAM links？（）

• A、A sham-link is created between any twoo VPN sites that belong to the same OSPF area and share an OSPF backdoor link
• B、A sham-link is seen as an intra-area link between PE routers，an OSPF adjacency is created and data base is exchanged
• C、A SHAM link is created between two directly connected PE routers so that it is preferred over the low speed backdoor door
• D、A SHAM link is part of OSPF network of MPLS-VPN provider

第14题：

Which statement is correct about an OSPF sham-link？（）

• A、A sham-link is a logical link between PE routers that provides an OSPF adjacency between the PE routers and forwards customer traffic across it.
• B、A sham-link is a logical link between PE routers that provides an OSPF adjacency between the PE routers and carries OSPF LSAs.
• C、A sham-link is a logical link between PE routers that carries OSPF LSAs and forwards customer traffic across it.
• D、A sham-link is a point-to-multipoint link that provides an OSPF adjacency between the PE routers and carries OSPF LSAs.
• E、A sham-link is a point-to-multipoint link that provides an OSPF adjacency between the PE routers and forwards customer traffic across it.

第15题：

When verifying the OSPF link state database, which type of LSAs should you expect to see within the different OS PF area types?（）

• A、All OSPF routers in stubby areas can have type 3 LSAs in their database.
• B、All OSPF routers in stubby areas can have type 7 LSAs in their database.
• C、All OSPF routers in totally stubby areas can have type 3 LSAs in  their database.
• D、All OSPF routers in totally stubby areas can have type 7 LSAs in their database.
• E、All OSPF routers in NSSA areas can have type 3 LSAs in their database.
• F、All OSPF routers in NSSA areas can have type 7 LSAs in their database.

第16题：

OSPF stub areas are an important tool for the Network designer； which of the following two shouldbe considered when utilizing OSPF stub areas？ （）

• A、 OSPF stub areas increase the size of the LSDB with the addition of Type 3 and 5 LSAs
• B、 OSPF not so stubby areas are particularly useful as a simpler form of summarization
• C、 OSPF stub areas are always insulated from external changes
• D、 OSPF totally stubby cannot distinguish among ABRs for the best route to destinationsoutsidethe areas
• E、 OSPF stub areas can distinguish among ASBRs for destinations that are external to the OSPFdomain

第17题：

Open Shortes t Path First (OSPF) is a routing protocol developed for Internet Protocol (IP) networks by the Interior Gateway Protocol (IGP) working group of the Internet Engineering Task Force (IETF). Which two statements best describe the OSPF link - state routing pro tocol?（）

• A、OSPF sends updates every 10 seconds
• B、OSPF sends triggered updates when a network change occurs
• C、When a link state is changed, the router that detected the change creates a link - state advertisement (LSA) and propagates it  to all OSPF devices using the 224.0.0.6 multicast address
• D、OSPF sends summaries of individual link- state entries every 30 minutes to ensure LSDB synchronization

第18题：

Which two items should you know when configuring OSPF to dynamically learn routes? （）(Choose two.)

• A、OSPF area ID
• B、OSPF neighbor address
• C、OSPF loopback address
• D、OSPF authentication type

第19题：

A network planning diagram shows a large internetwork with many routers. The configurations show that OSPF has been enabled on all interfaces, I P addresses correctly configured, and OSPF workinG. For which of the following cases would you expect a router to create and flood a Type 2 LSA?（）

• A、When OSPF is enabled on a LAN interface, and the router is the only router connected to the subnet.
• B、  When OSPF is enabled on a point - to -point serial link, and that router has both the higher router ID and higher interface IP address on the link.
• C、When OSPF is enabled on a Frame Relay point - to - point subinterface, has the lower RID and lower subinterfa ce IP address, and otherwise uses default OSPF configuration on the interface.
• D、When OSPF is enabled on a working LAN interface on a router, and the router has been elected BDR.
• E、None of the other answers is correct.

第20题：

Routers A and B have an OC12c and a GE link between them and are running OSPF over both of these links.Which item is correct， assuming the default JUNOS software OSPF metric calculation？（）

• A、There are two equal cost paths between A and B
• B、The GE link is the preferred path between A and B
• C、The OC12c link is the preferred path between A and B
• D、Manual metric assignment must be configured to determine the outcome.

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