ICND2 Chapter 14

Question 1

PPP LCP Feature: Magic Number

Answer 1

Looped Link detection; Detects if the link is looped and disables the interface; allowing rerouting over a working route.

Question 2

PPP LCP Feature: Link Quality Monitoring (LQM)

Answer 2

Error detection; Disables an interface that exceeds an error percentage threshold; allowing rerouting over better routes.

Question 3

PPP LCP Feature: Multilink PPP

Answer 3

Multilink Support; Load-balances traffic over multiple parallel links.

Question 4

PPP LCP Feature: PAP and CHAP

Answer 4

Authentication; Exchanges names and passwords so that each device can verify the identity of the device on the other end of the link.

Question 5

Serial Status: Admin down/Down; Likely reason

Answer 5

Interface is shut down

Question 6

Serial Status: Down/Down; Likely reason

Answer 6

Layer 1

Question 7

Serial Status: Up/Down; Likely reason

Answer 7

Layer 2

Question 8

Serial Status: Up/Up; Likely reason

Answer 8

Layer 3

Question 9

Serial Link: Up/Down (stable) on both ends

Answer 9

Mismatched encapsulation commands or PAP/CHAP authentication failure

Question 10

Serial Link: Up/Down (stable) on one end; flapping between up and down on the other

Answer 10

Mismatched encapsulation commands

Question 11

Serial Link: Up/Down on one end; up on the other

Answer 11

Keepalive is disabled on the end in an up state

Question 12

Symptoms When IP addresses on a Serial Link Are In Different Subnets: Does a Ping of the other router’s serial IP address work? (HDLC/PPP)

Answer 12

HDLC No; PPP Yes

Question 13

Symptoms When IP addresses on a Serial Link Are In Different Subnets: Can routing protocols exchange routes over the link? (HDLC/PPP)

Answer 13

HDLC No; PPP No