John is a new network administrator. One of his engineers has put in a request to implement an ISDN line, but the company already has an established WAN link. Why would the engineer suggest this?
A.
Out of band communication
B.
Signaling channel for control information
C.
Single point of failure
D.
Extranet communication
Explanation:
For WAN connections, a failover option should be configured to enable
an ISDN to be available if the WAN router fails. ISDN is just one type of technology
that can be implemented for this situation.