A network administrator cannot connect to a remote router by using SSH. Part of the show
interfaces command is shown.
router#show interfaces
Serial0/1/0 is up, line protocol is down
At which OSI layer should the administrator begin troubleshooting?
A.
physical
B.
data link
C.
network
D.
transport
Explanation:
The data link provides data transfer across the physical link.
Protocol examples – most forms of serial communication.
Layer 2 devices deliver frames using unique hardware addresses. A frame’s header contains source and destination addresses that indicate which device originated the frame and which device is expected to receive and process it. In contrast to the hierarchical and routable addresses of the network layer, layer-2 addresses are flat, meaning that no part of the address can be used to identify the logical or physical group to which the address belongs.
0
0
Start on the physical link
0
0