Refer to the exhibit.
As shown in the figure, RTA, RTB, RTC, and RTD are connected through a switch. From small to large in order of the MAC address, the four routers are arranged as follows:
RTB, RTA, RTD, and RTC. The Level-2 DIS priority is set to 100 on RTB and RTD, and IS-IS BFD is enabled on all these routers. When the links of RTB are down, how should IS-IS BFD sessions be set up?
Select an option, then click Submit answer.
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Level 1 and level 2 IS-IS BFD sessions are set up among RTA, RTC, and RTD.
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Level 2 IS-IS BFD sessions are set up among RTA, RTC, and RTD, and a level 1 IS-IS BFD session is set up between RTC and RTD.
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Level 2 IS-IS BFD sessions are set up between RTD and RTA as well as between RTD and RTC, and a level 1 IS-IS BFD session is set up between RTC and RTD.
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Level 1 and level 2 IS-IS BFD sessions are set up only between RTC and RTD
