In an OSPF network, an algorithm is used to prevent loops within an area, but loops may occur between areas. Therefore, OSPF defines a loop prevention mechanism for inter-area routes. Which of the…

IPv4 Routing Technologies

Question

In an OSPF network, an algorithm is used to prevent loops within an area, but loops may occur between areas. Therefore, OSPF defines a loop prevention mechanism for inter-area routes. Which of the following statements are true about the loop prevention mechanism? A. Inter-area routes cannot be directly transmitted between non-backbone areas. B. All non-backbone areas must be connected to backbone area 0. C. Inter-area routes need to be forwarded through area 0. D. An OSPF router inject Type 3 LSAs that describe routes to a network segment in an area back to the same area.

Explanation

The provided correct answer is 'ABCD', implying A, B, C, and D are all true. Based on the explanation, 'Strict adherence to hierarchical area design' and 'Prohibition of direct inter-area route exchanges between non-backbone areas' are key mechanisms. This directly supports statement A. The principle of hierarchical design and area 0 backbone's role implies B and C. Statement D, concerning Type 3 LSAs, typically describes routes into an area, not back to the same area for loop prevention in the sense of inter-area routing.

Topics

#OSPF inter-area routing#backbone area#Type 3 LSA#loop prevention

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