Open Shortest Path First (OSPF) was designed as an （ ） gateway protocol, for use in an autonomous system such as a local area network (LAN). It implements Dijkstra's algorithm, also known as the （ ） path first algorithm. As a link-state routing protocol it was based on the link-state algorithm developed for the ARPANET in 1980 and the IS-IS routing protocol. OSPF was first standardised in 1989 as RFC 1131, which is now known as OSPF version 1.Routing protocols like OSPF calculate the shortest route to a destination through the network based on an algorithm. The first routing protocol that was widely implemented, the （请作答此空）, calculated the shortest route based on hops, that is the number of routers that an IP packet had to traverse to reach the destination host. RIP successfully implemented dynamic routing, where routing tables change if the network topology changes. But RIP did not adapt its routing according to changing network conditions, such as data-transfer rate. Demand grew for a dynamic routing protocol that could calculate the fastest route to a destination. （ ） was developed so that the shortest path through a network was calculated based on the cost of the route, taking into account bandwidth, delay and load. Therefore OSPF undertakes route cost calculation on the basis of link-cost parameters, which can be weighted by the administrator. OSPF was quickly adopted because it became known for reliably calculating routes through large and complex local area networks.As a link state routing protocol, OSPF maintains link state （ ）, which are really network topology maps, on every router on which it is implemented. The state of a given route in the network is the cost, and OSPF algorithm allows every router to calculate the cost of the routes to any given reachable destination. Unless the administrator has made a configuration, the link cost of a path connected to a router is determined by the bit rate (1 Gbit/s, 10 Gbit/s, etc) of the interface. A router interface with OSPF will then advertise its link cost to neighbouring routers through multicast, known as the hello procedure. All routers with OSPF implementation keep sending hello packets, and thus changes in the cost of their links become known to neighbouring routers. The information about the cost of a link, that is the speed of a point to point connection between two routers, is then cascaded through the network because OSPF routers advertise the information they receive from one neighbouring router to all other neighbouring routers. This process of flooding link state information through the network is known as synchronisation. Based on this information, all routers with OSPF implementation continuously update their link state databases with information about the network topology and adjust their routing tables.OSPF has become a popular dynamic routing protocol. Other commonly used dynamic routing protocols are the RIP and the Border Gateway Protocol (BGP). Today routers support at least one interior gateway protocol to advertise their routing tables within a local area network. Frequently implemented interior gateway protocols besides OSPF are RIP, IS-IS, and the proprietary Interior Gateway Routing Protocol (IGRP) by Cisco.A.OSPFB.RIPC.IS-ISD.EIGRP
Open Shortest Path First (OSPF) was designed as an （ ） gateway protocol, for use in an autonomous system such as a local area network (LAN). It implements Dijkstra's algorithm, also known as the （ ） path first algorithm. As a link-state routing protocol it was based on the link-state algorithm developed for the ARPANET in 1980 and the IS-IS routing protocol. OSPF was first standardised in 1989 as RFC 1131, which is now known as OSPF version 1.Routing protocols like OSPF calculate the shortest route to a destination through the network based on an algorithm. The first routing protocol that was widely implemented, the （请作答此空）, calculated the shortest route based on hops, that is the number of routers that an IP packet had to traverse to reach the destination host. RIP successfully implemented dynamic routing, where routing tables change if the network topology changes. But RIP did not adapt its routing according to changing network conditions, such as data-transfer rate. Demand grew for a dynamic routing protocol that could calculate the fastest route to a destination. （ ） was developed so that the shortest path through a network was calculated based on the cost of the route, taking into account bandwidth, delay and load. Therefore OSPF undertakes route cost calculation on the basis of link-cost parameters, which can be weighted by the administrator. OSPF was quickly adopted because it became known for reliably calculating routes through large and complex local area networks.As a link state routing protocol, OSPF maintains link state （ ）, which are really network topology maps, on every router on which it is implemented. The state of a given route in the network is the cost, and OSPF algorithm allows every router to calculate the cost of the routes to any given reachable destination. Unless the administrator has made a configuration, the link cost of a path connected to a router is determined by the bit rate (1 Gbit/s, 10 Gbit/s, etc) of the interface. A router interface with OSPF will then advertise its link cost to neighbouring routers through multicast, known as the hello procedure. All routers with OSPF implementation keep sending hello packets, and thus changes in the cost of their links become known to neighbouring routers. The information about the cost of a link, that is the speed of a point to point connection between two routers, is then cascaded through the network because OSPF routers advertise the information they receive from one neighbouring router to all other neighbouring routers. This process of flooding link state information through the network is known as synchronisation. Based on this information, all routers with OSPF implementation continuously update their link state databases with information about the network topology and adjust their routing tables.OSPF has become a popular dynamic routing protocol. Other commonly used dynamic routing protocols are the RIP and the Border Gateway Protocol (BGP). Today routers support at least one interior gateway protocol to advertise their routing tables within a local area network. Frequently implemented interior gateway protocols besides OSPF are RIP, IS-IS, and the proprietary Interior Gateway Routing Protocol (IGRP) by Cisco.
A.OSPF
B.RIP
C.IS-IS
D.EIGRP
B.RIP
C.IS-IS
D.EIGRP
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●In the following essay，each blank has four choices．Choose the most suitable one from the four choices and write down in the answer sheet．Open Shortest Path First(OSPF)is a (66) routing algorithm that (67) work done on the OSI IS-IS intradomain routing protocol．This routing，as compared to distance-vector routing，requires (68) processing power．The Dijkstra algorithm is used to calculate (69) OSPF routing table updates only take place when necessary， (70) at regular intervals．(66) A．distance-vectorB．link-stateC．flow-basedD．selective flooding(67) A．derived fromB．deviated fromC．was derived fromD．was deviated from(68) A．moreB．lessC．sameD．most(69) A．routesB．roadC．distanceD．cost(70) A．but ratherB．rather tooC．rather thanD．rather that
根据下面的文字资料回答 71～75 题 n the following essay，each blank has four choices．Choose the most suitable one from the four choices and write down in the answer sheet．Open Shortest Path First(OSPF)is a（ 1 ）routing algorithm that（ 2 ）work done on the OSI IS-IS intradomain routing protocol．This routing，as compared to distance-vector routing，requires（ 3 ）processing power．The Dijkstra algorithm is used to calculate（ 4 ）OSPF routing table updates only take place when necessary，（ 5 ）at regular intervals．第6题：文中（ 1 ）处正确的答案是（ ）。A．distance-vectorB．link-stateC．flow-basedD．selective flooding
●Border Gateway Protocol(BGP) is inter-autonomous system (71) protocol. BGP is based on a routing method called path vector routing. Distance vector routing is not a good candidate for inter-autonomous system routing because there are occasions on which the route with the smallest (72) count is not the preferred route. For example, we may not want a packet through an not secure even though it is the shortest route. Also, distance vector routing is unstable due to the fact that the routers announce only the number of hop counts to the destination without actually defining the path that leads to that (73) ．A router that recevives a distance vector advertisement packet may be fooled if the shortest path is actually calculated through the receiving router itself. Link (74) routing is also not a good candidate for inter-autonomous system routing because an Internet is usually too big for this routing method. To use link state routing for the whole internet would require each routex to have a huge link state database. It would also take a long time for each router to calculate its rousting (75) using the Dijkstra algorism.（71）A. routingB. switchingC. transmittingD. receiving(72)A. pathB. hop `C. routeD. packet(73）A. connectionB. windowC. sourceD. destination(74)A. statusB. searchC. stateD. research(75）A. tableB. stateC. metricD. cost
OSPF is a link-state routing protocol。It is designed to be run internal to a single __（71__system。Each OSPF router maintains an identical __（72）__ describing the autonomous system’s topology。From this database，a routing table is calculated by constructing a shortest-path __（73）__。OSPF recalculates routes quickly in the face of topological changes，utilizing a minimum of routing __（74）__ traffic。OSPF provides support for equal-cost multipath。An area routing capability is provided，enabling an additional level of routing protection and a reduction in routing protocol __（75）__。A.autonomousB.networkC.computerD.server
OSPF is a link-state routing protocol。It is designed to be run internal to a single __（71）__system。Each OSPF router maintains an identical __（72）__ describing the autonomous system’s topology。From this database，a routing table is calculated by constructing a shortest-path __（73）__。OSPF recalculates routes quickly in the face of topological changes，utilizing a minimum of routing __（74）__ traffic。OSPF provides support for equal-cost multipath。An area routing capability is provided，enabling an additional level of routing protection and a reduction in routing protocol__（75）__。71A.autonomousB.networkC.computerD.server
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 secondsB. OSPF sends triggered updates when a network change occursC. 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 addressD. OSPF sends summaries of individual link- state entries every 30 minutes to ensure LSDB synchronization
Which command displays the number of times that the OSPF Shortest Path First (SPF) algorithm has been executed?() A. show ip protocolB. show ip ospfC. sho w ip ospf databaseD. show ip ospf interface
Into which two types of areas would an area border router (ABR) inject a default route?() A. stubB. the autonomous system of an exte rior gateway protocol (EGP)C. NSSAD. totally stubbyE. the autonomous system of a different interior gateway protocol (IGP)F. area 0
Distribution layer: This layer includes LAN－based routers and layer 3 switches . When is a first－hop redundancy protocol needed in the distribution layer?() A. OSPF is not supported by the designB. HSRP is not supported by the designC. preempt tuning of the default gateway is neededD. the design implements Layer 3 between the access switch and the distribution switch
OSPF is a link-state routing protocol。It is designed to be run internal to a single （71）system。Each OSPF router maintains an identical （）describing the autonomous system’s topology。From this database，a routing table is calculated by constructing a shortest-path （）。OSPF recalculates routes quickly in the face of topological changes，utilizing a minimum of routing （） traffic。OSPF provides support for equal-cost multipath。An area routing capability is provided，enabling an additional level of routing protection and a reduction in routing protocol （）。A.autonomous B.network C.computer D.server
What does the command clear ipv6 ospf process accomplish?（）A、The shortest path first (SPF) algorithm is performed on the LSA database.B、The OSPF adjacencies are cleared and initiated again.C、The OSPF database is repopulated. Then the shortest path first (SPF) algorithm is performed.D、The route table is cleared. Then the OSPF neighbors are reformed.
You have a router running BGP for the MPLS network and OSPF for the local LAN network at the sales office. A route is being learned from the MPLS network that also exists on the OSPF local network. It is important that the router chooses the local LAN route being learned from the downstream switch running OSPF rather than the upstream BGP neighbor. Also， if the local OSPF route goes away， the BGP route needs to be used. What should be configured to make sure that the router will choose the LAN network as the preferred path？（）A、static route needs to be addedB、floating static route needs to be addedC、bgp backdoor commandD、ospf backdoor command
The command "clear ipv6 ospf process" was issued on a router. What does this commandaccomplish？（）A、The route table is cleared. Then the OSPF neighbors are reformedB、The OSPF adjacencies are cleared and initiated againC、The OSPF database is repopulated and then the shortest path first （SPF） algorithm isperformed.D、The shortest path first （SPF） algorithm is performed on the LSA databaseE、None of the other alternatives apply
Distribution layer: This layer includes LAN-based routers and layer 3 switches . When is a first-hop redundancy protocol needed in the distribution layer?（）A、OSPF is not supported by the designB、HSRP is not supported by the designC、preempt tuning of the default gateway is neededD、the design implements Layer 3 between the access switch and the distribution switch
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 secondsB、OSPF sends triggered updates when a network change occursC、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 addressD、OSPF sends summaries of individual link- state entries every 30 minutes to ensure LSDB synchronization
A router has two paths to reach another network in a different autonomous system. Neither route was generated by the local router and both routes have the same default weight an d local preference values. Which statement is true about how BGP would select the best path?（）A、To influence one route to be preferred, its default local preference value will be changed via the use of the command bgp default local - preference 50B、Th e router will prefer the shortest autonomous system pathC、If the command bgp always - compare - med has been given, then the router will prefer the route with the highest MEDD、The router will prefer the route with the lower MED
What does a router do?（）A、Routes traffic down alternative paths and connects the local-area network (LAN) to the wide- area network (WAN)B、Reads Media Access Control (MAC) addresses to forward messages to the correct location and connects the local-area network (LAN) to the wide-area network (WAN)C、Stores data on the network and connects the local-area network (LAN) to the wide-area network (WAN)D、Broadcasts data to all devices that are connected to it across the local-area network (LAN) and wide-area network (WAN)
Into which two types of areas would an area border router (ABR) inject a default route?（）A、stubB、the autonomous system of an exte rior gateway protocol (EGP)C、NSSAD、totally stubbyE、the autonomous system of a different interior gateway protocol (IGP)F、area 0
多选题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?（）AOSPF sends updates every 10 secondsBOSPF sends triggered updates when a network change occursCWhen 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 addressDOSPF sends summaries of individual link- state entries every 30 minutes to ensure LSDB synchronization
多选题Into which two types of areas would an area border router (ABR) inject a default route?（）AstubBthe autonomous system of an exte rior gateway protocol (EGP)CNSSADtotally stubbyEthe autonomous system of a different interior gateway protocol (IGP)Farea 0
单选题You have a router running BGP for the MPLS network and OSPF for the local LAN network at the sales office. A route is being learned from the MPLS network that also exists on the OSPF local network.It is important that the router chooses the local LAN route being learned from the downstream switch running OSPF rather than the upstream BGP neighbor. Also，if the local OSPF route goes away，the BGP route needs to be used. What should be configured to make sure that the router will choose the LAN network as the preferred path？（）Astatic route needs to be addedBfloating static route needs to be addedCbgp backdoor commandDospf backdoor command
单选题A router has two paths to reach another network in a different autonomous system. Neither route was generated by the local router and both routes have the same default weight an d local preference values. Which statement is true about how BGP would select the best path?（）ATo influence one route to be preferred, its default local preference value will be changed via the use of the command bgp default local - preference 50BTh e router will prefer the shortest autonomous system pathCIf the command bgp always - compare - med has been given, then the router will prefer the route with the highest MEDDThe router will prefer the route with the lower MED
单选题The command "clear ipv6 ospf process" was issued on a router. What does this commandaccomplish？（）AThe route table is cleared. Then the OSPF neighbors are reformedBThe OSPF adjacencies are cleared and initiated againCThe OSPF database is repopulated and then the shortest path first （SPF） algorithm isperformed.DThe shortest path first （SPF） algorithm is performed on the LSA databaseENone of the other alternatives apply
单选题Which command displays the number of times that the OSPF Shortest Path First (SPF) algorithm has been executed?（）Ashow ip protocolBshow ip ospfCsho w ip ospf databaseDshow ip ospf interface