CCNA Review

Question 1

What are the DTE and DCE in frame relay?

Answer 1

DTE (data terminal equipment) are the routers that consume the frame relay. DCE (data communication equipment) are the frame relay switches that provide clocking and switching.

Question 2

What is the difference between SVCs and PVCs?

Answer 2

Switched virtual circuits (SVC) are setup when needed and then torn down. Private virtual circuits (PVC) are predefined and similar to a leased line.

Question 3

Define DLCI

Answer 3

Data-link connection identifiers (DLCI) are locally significant identifiers for logical circuits.

Question 4

What are static versus dynamic DLCIs?

Answer 4

Static DLCIs are configured manually. Dynamic DLCIs use inverse arp requests to ascertain the IP addresses of their neighbors.

Question 5

What is the command to configure a static DLCI?

Answer 5

frame-relay map ip 10.0.0.100 22 broadcast

Broadcast is used here so that routing protocols can overcome split-horizon (but it’s “pseudo-broadcast”, since updates will be sent unicast to each neighbor).

Question 6

What is a side-effect of adding a static frame-relay neighbor?

Answer 6

Inverse arp will be disabled for the protocol in the static map on that DLCI.

Question 7

Give the command for verifying a successful frame-relay topology?

Answer 7

show frame-relay map

Question 8

What is LMI?

Answer 8

Local management interface (LMI) is the signalling protocol used between the router and DCE, which includes keepalives as well as DLCI information.

Question 9

What is the default protocol on serial interfaces?

Answer 9

HDLC (High-level Data Link Control), which is a point-to-point protocol and does not support subinterfaces.

Question 10

Give the command to enable frame-relay on interface Serial0/0

Answer 10

interface Serial0/0

encapsulation frame-relay

Question 11

Give the command to determine whether frame-relay circuits are up

Answer 11

sh frame-relay pvc

Question 12

Under what circumstances can inverse arp function?

Answer 12

Only on physical interfaces, not on sub-interfaces.

Question 13

Give the command to map a static neighbor on frame-relay.

Answer 13

interface Serial0/0.100

frame-relay map ip X.X.X.X

Question 14

Give the command to see the frame-relay settings.

Answer 14

sh frame-relay map

Question 15

What is the clue that indicates a network type doesn’t use a DR or BDR?

Answer 15

If it starts with “point”, it doesn’t elect a DR or BDR.

Question 16

What is the clue that indicates a network type doesn’t perform dynamic discovery?

Answer 16

If it has the words “non-broadcast”, it requires static neighbor mappings.

Question 17

Which network types use the default timers?

Answer 17

Only the plainest two names - “broadcast” and “point-to-point” have times of 10 seconds / 40 seconds.