A network administrator needs to configure a serial link between the main office and a remote
location. The router at the remote office is a non-Cisco router. How should the network
administrator configure the serial interface of the main office router to make the connection?

A.
Main(config)# interface serial 0/0 Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# no shut

B.
Main(config)# interface serial 0/0 Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation ppp Main(config-if)# no shut

C.
Main(config)# interface serial 0/0 Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation frame-relay Main(config-if)# authentication chap Main(config-if)# no
shut

D.
Main(config)# interface serial 0/0 Main(config-if)#ip address 172.16.1.1 255.255.255.252
Main(config-if)#encapsulation ietf Main(config-if)# no shut

Explanation:
Cisco High-Level Data Link Controller (HDLC) is the Cisco proprietary protocol for sending data over
synchronous serial links using HDLC. So HDLC runs only in Cisco router. PPP is not proprietary
protocol it’s a open source every cisco router and non-cisco router understand the PPP protocol.So
we need to configure the PPP protocol if connection is between cisco and non-cisco router.