[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] 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] 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).

[判断题]电阻R1，R2并联，已知R1＞＞R2，并联后的等值电阻近似等于R1，即R≈R1。

[填空题]电阻R₁和R₂串联，已知R₂＝4R₁，若R₂两端电压U₂=16V，则R₁两端电压U₁＝（）。

[单项选择]ABR R1 has been configured with an area 1 stub no - summary command. Which stubby area type is area 1?（）
A. Stub
B. Totally stubby
C. NSSA
D. Totally NSSA

[单项选择]设关系R1有r1个元组，关系R2有r2个元组，则关系R1和R2连接后的结果关系的元组数目是 ______ 个。
A. r1+r2
B. ri*r2
C. ≤r1*r2
D. ≥r1*r2

[多项选择] Routers R1 and R2 are EIGRP neighbors. R1 has been configured with the eigrp stub connected command. Which of the following is true as a result？（）
A. R1 can learn EIGRP routes from R2, but R2 cannot learn EIGRP routes from R1
B. R1 can send IP packets to R2, but R2 cannot send IP packets to R1
C. R2 no longer learns EIGRP routes from R1 for routes not connected to R1
D. R1 no longer replies to R2's Query messages
E. R2n o longer sends to R1 Query messages

[单项选择]在电路中R1和R2并联，R1＝2Ω，R2＝4Ω，则它们的电流比I1：I2＝（）。
A. 1：2
B. 1：4
C. 2：1
D. 4：1

[判断题]表达式"R1=R2+R3*SIN（R4）"的运算次序依次为SIN（R4），R3*SIN（R4），R2+R3*SIN（R4）（SIEMENS系统）。

[单项选择] 在电路中R₁和R₂并联，R₁=2Ω，R₂=4Ω，则它们的电流比I₁：I₂=（）。
A. 1∶2
B. 1∶4
C. 2∶1
D. 4∶1

[单项选择]如下两个关系R1和R2，它们进行何种运算后得到R3R1

[单项选择] Router B1, an internal router in area 1, displays the following output. The only two ABRs connected to area 1 are performing Type 3 LSA filterinG. Which of the following answers is true based on the information in the output from B1?（） R1# show ip route 10.1.0.0 255.255.0.0 longer - prefixes ! Legend lines omitted for brevity 10.0.0.0/8 is variably subnetted, 17 subnets, 3 masks O 10.1.2.0/24 [110/658] via 10.10.13.1, 00:00:32, Serial0/0/0.1 O IA 10.1.1.0/24 [110/658] via 10.10.23.2, 00:41:39, Ser ial0/0/0.2 O IA 10.1.3.0/24 [110/658] via 10.10.23.2, 00:41:39, Serial0/0/0.2
A. A Type 3 LSA for 10.2.2.0/24 was filtered by both ABRs
B. A Type 3 LSA for 10.1.2.0/24 was not filtered by both ABRs
C. A Type 3 LSA for 10.1.3.0/24 was not filtered by  at least one ABR
D. A Type 3 LSA for 10.1.1.0/24 filtered by both ABRs

[单项选择]在电路中R1和R2并联，R1=2Ω，R4=4Ω，则它们电流比I1： I2=（）。
A. 1：2
B. 1：4
C. 2：1
D. 4：1

[单项选择] A network de sign shows area 1 with three internal routers, area 0 with four internal routers, and area 2 with five internal routers. Additionally, one ABR (ABR1) connects areas 0 and 1, plus a different ABR (ABR2) connects areas 0 and 2. How many Type 1 LSAs would b e listed in ABR2's LSDB?（）
A. 6
B. 7
C. 15
D. 12
E. None of the other answers is correct.

[判断题]已知R1=5Ω，R2=10Ω，把R1、R2串联起来，并在其两端加15V的电压，此时R1所消耗的功率是5W。

[单项选择]R₁和R₂并联，其功率之比P₁：P₂=1：2，并联的等效电阻为2Ω，则R₁=（）。
A. 6Ω
B. 7Ω
C. 8Ω
D. 9Ω

[多项选择] Routers R1, R2, R3, and R4 connect to the same 10.10.10.0/24 LAN- based subnet. OSPF is fully working in the subnet. Later, R5, whose OSPF priority is higher than the other four routers, joins the subnet. Which of the following are true about the OSPF database exchange process over this subnet at this point?（）
A. R5 will send its DD, LSR, and LSU packets to the 224.0.0.5 all - DR - routers multicast address.
B. R5 will send its DD, LSR, and LSU pack ets to the 224.0.0.6 all - DR - routers multicast address.
C. The DR will inform R5 about LSAs by sending its DD, LSR, and LSU packets to the 224.0.0.6 all- SPF - routers multicast address.
D. The DR will inform R5 about LSAs by sending its DD, LSR, and LSU pa ckets to the 224.0.0.5 all- SPF - routers multicast address.