The following are functions of the access layer ________. (Choose one or more)

The description of NET in IS-IS is wrong.

As shown in the figure, 4 routers are connected to an Ethernet link. The router interface is a broadcast network type. Judging from the information in the figure, there are ________ IS-IS adjacencies on the Ethernet link.

In the network as shown in the figure, OSPF 100 runs on RTA, RTB, and RTC, and RTA and RTB establish EBGP neighbor relationships with RTD respectively.

AS 200 advertises route 10.10.10.0/24 to AS 100, and sets the MED value of the route advertised to RTA to 100, and the MED value of the route advertised to RTB is 200.
The main configurations of RTA and RTB are as follows:
RTA]
bgp 100
peerRTD as-number 200
peerRTB as-number 100
ospf 100
import-route bgp cost 10
RTB]
bgp 100
peerRTD as-number 200
peerRTA as-number 100
ospf 100
import-route bgp cost 20
The user wants RTC to prefer RTA when accessing 10.10.10.0/24, but it turns out that RTC chooses RTB for data forwarding.
How should the appeal issue be resolved?

In the IS-IS network as shown in the figure, RTA, RTC, RTD, and RTE establish a Level-2 adjacency relationship with each other; RTB establishes a Level-1 adjacency relationship with RTA, RTC. After the routing of each router is stable, when RTB accesses 192.168.14.1, it chooses the next hop as _________.
If RTA and RTC are added the following configuration at this time:
RTA-isis-1]import-route isis level-2 into level-1
RTC-isis-1]import-route isis level-2 into level-1
Then RTB selects the next hop as ________ when accessing 192.168.14.1.