单选题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 0B 1C 2D 3

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第2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3题：

While troubleshooting an EIGRP routing problem you notice that one of the routers have generated a large number of SIA messages. What are two possible causes for EIGRP Stuck - In -Active routes?（）

• A、Some quer y or reply packets are lost between the routers.
• B、The neighboring router starts receiving route updates from this router.
• C、A failure causes traffic on a link between two neighboring routers to flow in only one direction(unidirectional link).
• D、Th e neighboring router stops receiving ACK packets from this router.

第4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5题：

Routers A and B are connected with a point-to-point OC-3 interface. Each routers OC-3 interface is configured for both Level 1 and Level 2. The routers are configured in different areas. How many IS-IS adjacencies exist between the two routers?（）

• A、0
• B、1
• C、2
• D、3

第6题：

While troubleshooting an EIGRP routing problem you notice that one of the company routers havegenerated a large number of SIA messages. What are two possible causes for EIGRP Stuck-In-Active routes？（）

• A、Some query or reply packets are lost between the routers
• B、The neighboring router starts receiving route updates from this router
• C、A failure causes traffic on a link between two neighboring routers to flow in only one direction（unidirectional link）
• D、The neighboring router stops receiving ACK packets from this router

第7题：

Which two statements are correct regarding IS-IS？（）

• A、Routers maintain a single link-state database per area.
• B、Routers maintain a separate Level 1 link-state database.
• C、Routers maintain a separate Level 2 link-state database.
• D、Routers maintain a single Level 1 link-state database per area.

第8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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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：

Beginning with software version 4-0-0.rel，how many virtual routers canbe configured on the ERX Edge Router？（）

• A、32
• B、128
• C、256
• D、1000

第16题：

Which two are characteristics of link-state routing protocols?（） (Choose two.)

• A、Routers choose a best path for a destination based on the SPF algorithm.
• B、All routers in a given area or level build a consistent database describing the network's topology.
• C、Routers choose the best path for a destination based on the interface on which they received the link stateadvertisement with the lowest cost.
• D、All routers in a given area or level forward link state advertisements between interfaces in the same area or level, adding their metric to the link state advertisement's cost information when they forward it.

第17题：

Your ERX router is supporting 100 virtual routers. A specific line module supports IP interfaces in 5 virtual routers.How many routing tables are maintained on that module?（）

• A、0
• B、1
• C、5
• D、100

第18题：

What information does a router running a link-state protocol use to build and maintain its topological database？ （）

• A、 hello packets
• B、 SAP messages sent by other routers 
• C、 LSAs from other routers
• D、 beacons received on point-to-point links
• E、 routing tables received from other link-state routers
• F、 TTL packets from designated routers

第19题：

Routers A and B are connected with a point-to-point OC-3 interface. Each router’s OC-3 interface is configured for both Level 1 and Level 2. The routers are configured in different areas.How many IS-IS adjacencies exist between the two routers？（）

• A、0
• B、1
• C、2
• D、3

第20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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