[单项选择] Router R1 sits inside OSPF area 1. Router R2 redistributes an E1 route into OSPF for prefix 2.2.2.0/24, with external metric 20. Router R22 redistributes an E2 route for the same prefix/length, external metric 10. Under what conditions will R1 choose as it s best route the route through R22?（）
A. R1 will always choose the route through R22.
B. As long as R1's best internal OSPF cost to reach R22 is less than 10.
C. As long as R1's best internal OSPF cost to reach R22 is less than 20.
D. R1 will never choo se the route through R22 if the E1 route through R2 is available.

[多项选择] Routers R1 and R2, OSPF neighbors in area 0 over their Fa0/0 interfaces (respectively), currently both successfully use OSPF MD5 authentication. The OSPF configuration includes the area 0 authentication command under the router ospf 1 command. Which of the following commands must have been configur ed on R1's Fa0/0 interface?（）
A. ip ospf authentication null
B. ip ospf authentication message - digest
C. ip ospf authentication -key whatever- it - is
D. ip ospf message - digest - key 1 md5 whatever - it - is
E. ip ospf md5 1 key whatever - it - is

[多项选择]The maximum number of routers per OSPF area typically depends on which three factors?（）
A. the kind of OSPF areas being implemented
B. the number of external LSAs in the network
C. the number of DRs and BDRs in the areas
D. the number of virtual links in the areas
E. how well the areas can be summarized
F. the use of LSA filters

[多项选择]To make OSPF area 4 totally stubby, the following command was issued on the ABR in router configuration mode: area 4 stub.Which two things need to be done to finish making area 4 a totally stubby area?（）
A. Apply the area 4  stub command to all routers in the area
B. On the ABR, use the area 4 stub command with the no - summary keyword
C. On the ABR, specify a default cost for the area with the area default - cost command
D. On the ABR, use the default - information originate  command to inject a default route into area 4
E. Use the auto - cost command on each router in the area to automatically determine the cost to other OSPF areas

[单项选择]Which OSPF area type allows for the flooding of a Type 7 LSA?（）
A. stub
B. transit
C. border
D. not-so-stubby

[单项选择]Which of the following is true about an OSPF area border router (ABR)?（）
A. The ABR must have multiple interfaces connected to the backbone areA
B. An ABR is a router with two interfaces, each connected to a different nonbackbone areA
C. The only requirement to be considered an  ABR is at least one interface connected to the backbone areA
D. An ABR must have at least one interface in the backbone area plus at least one other interface in a nonbackbone areA

[多项选择]What are two benefits of using a single OSPF area network design?（）
A. it reduces the number of required OSPF neighbor adjacencies
B. It reduces the types of LSAs that are generated
C. It is less CPU intensive for routers in the single area
D. It increases LSA response times.
E. It removes the need for virtual links

[多项选择] Routers R1 and R2 are OSPF neighbors using their Fa0/0 interfaces, respectively, using default settings for all timers. An engineer ad ds the ip ospf hello - interval 6 command to R1's Fa0/0 configuration. Which of the following is true regarding the results from this change?（）
A. The show ip ospf neighbor command on R1 lists the revised Hello timer
B. The show ip ospf interfac e brief command on R1 lists the revised Hello timer
C. The R1 - R2 neighborship fails due to Hello timer mismatcH
D. The show ip ospf interface command on R1 lists the revised Hello timer

[简答题]OSPF的域间路由通告行为？问R1能够将AREA 1通告给AREA 0的域间路由在通告回AREA 1吗？为什么？

[单项选择] Router R1 is redistributing between two OSPF processes. Given the configuration shown, which includes all commands in the route map named fred, which of the following answers is true regarding the redistribution into OSPF process 1?（） router ospf 1 redistribute ospf 2 external 2 route - map fred ! route - map fred permit 10 match ip address 1 set metric - type type - 1
A. No routes are redistributed because a route cannot be both E1 and E2.
B. Only OSPF E2 routes in the OSPF 2 domain will be considered for redistribution.
C. Inside the OSPF 2 domain, any formerly E2 routes will become E1 routes.
D. Routes permitted by ACL 1 will be redistributed, regardless of whether the routes are E1 or E2 routes.

[单项选择] 下列配置中，R1的OSPF路由器ID是（） R1（config）#interface  s0/0/0  R1（config-if）#ip add 192.168.2.1 255.255.255.252 R1（config）#int loopback 0  R1（config-if）#ip add 10.1.1.1 255.255.255.255 R1（config）#router ospf 1  R1（config-if）#network 192.168.2.0 0.0.3.255 area 0
A. 192.168.2.1
B. 10.1.1.1
C. 192.168.2.0
D. 255.255.255.255

[单项选择] R1 is internal to area 1, and R2 is internal to area 2. Subnet 10.1.1.0/24 exists in area 2 as a connected subnet off R2. ABR ABR1 connects area 1 to backbone area 0, and ABR2 c onnects area 0 to area 2. Which of the following LSAs must R1 use when calculating R1's best route for 10.1.1.0/24?（）
A. R2's Type 1 LSA
B. Subnet 10.1.1.0/24's Type 2 LSA
C. ABR1's Type 1 LSA in area 0
D. Subnet 10.1.1.0/24's Type 3 LSA in Area 0
E.   Subnet 10.1.1.0/24's Type 3 LSA in Area 1

[单项选择] 请问以下配置中，R1的OSPF路由器ID是什么（） R1（config）#interface s0/0/0  R1（config-if）#ip add 192.168.2.1 255.255.255.252 R1（config）#int loopback 0  R1（config-if）# ip add 10.1.1.1 255.255.255.255 R1（config）#router ospf 1  R1（config-if）#network 192.168.2.0 0.0.3.255 area 0
A. 192.168.2.1
B. 10.1.1.1
C. 192.168.2.0
D. 255.255.255.255

[多项选择] Router R1 sits at an Enterprise branch office, using both the Internet and a leased line to another Enterprise router for its two connectivity options back into the rest of the Enterprise network. The engineer planning for this branch decided to use the leased line for all Enterprise traffic, unless it fails, in which case the Internet connection should be used to pass traffic to the Enterprise. Which of the following is most likely to be useful on the branch router?（）
A. IPsec tunnel
B. GRE tunnel
C. Floating stati c route
D. An IGP

[单项选择] Router R1 sits at an Enterprise branch office, using the Internet for its only connectivity back to the rest of the EnterprisE. Which of the following is not a ben efit of using an IPsec tunnel for packets sent through the Internet, between R1 and the rest of the Enterprise?（）
A. Privacy
B. Authentication
C. Allows using an IGP between R1 and the Enterprise
D. Secure communications

[判断题]OSPF协议一定要有AREA0。

[填空题]如果一个OSPF中只有一个area，那么这个area的ID是（）

[单项选择]An OSPF non-backbone area allows external routes to be flooded within the area. These externalroutes are propagated into other areas. However, external routes from other areas are not allowed to enter this area. Which type of OSPF area does this describe?（）
A. stub area
B. transit area
C. border area
D. not-so-stubby area

[单项选择]If all OSPF routers in a single area are configured with the same priority value,what value dose a router use for the ODPF router ID in the absence of a loopback interface?（）
A. the IP address of the first Fast Ethernet interface
B. the IP address of the console management interface
C. the highest IP address among its active interfaces
D. the lowest IP address among its active interfaces
E. the priority value until a loopback interface is configured

[多项选择] R1, an ABR between backbone area 0 and area 1, has intra - area routes in area 0 for 10.1.1.0/24,10.1.2.0/24, and 10.1.3.0/24. These routes have metrics of 21, 22, and 23, respectively. An engineer then adds the area 0 r ange 10.1.0.0 255.255.0.0 command under the OSPF process of R1. Which of the following is true?（）
A. R1 loses and then re - establishes neighborships with all neighbors.
B. R1 no longer advertises 10.1.1.0/24 to neighbors into area 1.
C. R1 advertises a 1 0.1.0.0/16 route into area 1 with a metric of 23 (largest metric).
D. R1 advertises a 10.1.0.0/16 route into area 1 with metric of 21 (lowest metric).