Question 848 of 952 from exam 200-125: Cisco Certified Network Associate Exam
Question
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?
Answers
Explanations
C
The correct answer is C. 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
Explanation:
When connecting a Cisco router to a non-Cisco router, the encapsulation protocol used should be PPP (Point-to-Point Protocol). PPP is an industry-standard protocol that is widely used for connecting routers together over serial links.
The configuration steps to set up a serial link using PPP are as follows:
Enter global configuration mode: Main(config)#
Configure the serial interface: Main(config)# interface serial 0/0
Configure the IP address and subnet mask for the interface: Main(config-if)# ip address 172.16.1.1 255.255.255.252
Configure the encapsulation protocol as PPP: Main(config-if)# encapsulation PPP
Enable the interface: Main(config-if)# no shut
Option A is incorrect because the "ietf" encapsulation protocol is not supported on Cisco routers.
Option B is incorrect because it does not specify the encapsulation protocol. By default, the encapsulation protocol is Cisco's HDLC, which is not compatible with non-Cisco routers.
Option D is incorrect because it specifies the Frame Relay encapsulation protocol, which is not appropriate for a point-to-point link. Additionally, the authentication method specified (CHAP) is not necessary for a simple point-to-point link.
