Test your basic knowledge |

CCENT

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Subnetting: What is a 255.255.255.0 in prefix notation
255.255.192.0
/24
By default - the flush timer is set for 240 seconds - which is 60 seconds longer than the invalid timer. When the flush timer expires - the route is removed from the routing table.
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE

2. Name the OSI Layers
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
IEEE 802.3z
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical

3. OSPF: What Algorithm is used?
Frames
2 hosts
DCE
Shortest path first - (SPF)

4. Subnetting: What is a 255.128.0.0 in prefix notation
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
/9
Frames
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change

5. How many Collision domains are there on a with 1 hub and 2 computers?
Packets
180
1 - everything hooked to the hub is in the same collision domain
120

6. What is the layer 4 PDU called?
/24
Segments
R
/9

7. RIP: What is the default Administrative Distance?
60
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)
120
Add the magic number to the network minus 1

8. RIP Timers: What is an Holddown Timer?
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
This timer stabilizes routing information and helps prevent routing loops during periods when the topology is converging on new information. Once a route is marked as unreachable - it must stay in holddown long enough for all routers in the topology
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet

9. Rip: What does v2 have that v1 does not?
Pins 1+2 swap places with pins 3+6
Presentation
255.255.0.0
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization

10. RIP: What Algorithm is used in RIP>
Bellman-Ford
/9
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical
The metric is called cost - and refers to the speed of the port - IE 56kps = 1785 where Fast Ethernet = 1

11. Rip Timers: How long is the default for Invalid timer.
Query and other router responds with a REPLY packet.
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
180 seconds
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization

12. RIP Timers: What is an Flush Timer?
/22
By default - the flush timer is set for 240 seconds - which is 60 seconds longer than the invalid timer. When the flush timer expires - the route is removed from the routing table.
Every 8 ip's
1:O/W - 2:Orange - 3:G/W - 4:Blue - 5:B/W - 6:Green - 7:Brown/W - 8:Brown

13. Subnetting: How many hosts per network if the subnet mask is 255.255.255.252
Segments
Router(config)#hostname R1 - R1(config)#line VTY 0 4 - R1(config-line)#login local - R1(config-line)#transport input telnet ssh - R1(config-line)#exit - R1(config)#username {user} password {pass} - R1(config)#ip domain-name {domainname} - R1(config)#
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
2 hosts

14. Subnetting: where do the networks break with a /25

15. What is the metric for RIP
2 - each port is it's own collision domain
Hop Count
1:G/W - 2:Green - 3:O/W - 4:Blue - 5:B/W - 6:Orange - 7:Brown/W - 8:Brown
It adds the cost of each jump - R1 to R2 over a t1 is a cost of 64 - R2 to computer is a cost of 1. Total cost of route is 65

16. EIGRP: What packet is used to search for networks?
Query and other router responds with a REPLY packet.
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
Closest multiple of the magic number that is not over the interesting octets number.
F an update has not been received to refresh an existing route after 180 seconds (the default) - the route is marked as invalid by setting the metric to 16. The route is retained in the routing table until the flush timer expires.

17. Subnetting: What is a 255.255.255.240 in prefix notation
/28
Every 8 ip's
Presentation
Hop Count

18. Subnetting: What is a /16 in Decimal
Presentation
30 per network
255.255.0.0
100

19. RIP Timers: What is an invalid Timer?
Periodic Updates of their routing table
F an update has not been received to refresh an existing route after 180 seconds (the default) - the route is marked as invalid by setting the metric to 16. The route is retained in the routing table until the flush timer expires.
Every 4 ip's
Router(config)#ip route {exit-interface}

20. Rip: how do hold down timers work?
2 hosts
1. Router receives update from neighbor indicating a route down - Router makes route as down and starts holddown timer - If router gets an update indicating route is back holddown is removed - If an update is received indicating route is down again i
180 seconds
Query and other router responds with a REPLY packet.

21. CABLES: What is the difference between T568A and T568B?
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
Pins 1+2 swap places with pins 3+6
1:G/W - 2:Green - 3:O/W - 4:Blue - 5:B/W - 6:Orange - 7:Brown/W - 8:Brown
Router(config)#ip route {exit-interface}

22. IEEE Standards: Gibabit Ethernet (Copper)
R
/9
Network
IEEE 802.3ab

23. What is Layer 2 in the OSI Model?
Segments
Data-Link
Switch forwards the frame as soon as it can
180

24. How do you find the magic number for subnetting?
255.255.255.128
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
Periodic Updates of their routing table

25. Rip Timers: How long is the default for Holddown timer.
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization
180
Frames
Every 32 ip's

26. OSPF: Commands to enable OSPF area 0 and advertise network 10.1.1.1 /28
Data-Link
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
IEEE 802.3z
Bandwidth - Delay - reliability and Load

27. How many Collision domains are there on a with 1 switch 2 computers?

28. Using the magic number how to you figure the broadcast?
Add the magic number to the network minus 1
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
It adds the cost of each jump - R1 to R2 over a t1 is a cost of 64 - R2 to computer is a cost of 1. Total cost of route is 65
Switch forwards frame once it completely receives it

29. What is the Data-Link PDU called?
Frames
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
IEEE 802.3ab
By default - the flush timer is set for 240 seconds - which is 60 seconds longer than the invalid timer. When the flush timer expires - the route is removed from the routing table.

30. Subnetting: where do the networks break with a /26

31. Switching Methods: What is Store and Forward?
Frames
Data-Link
Switch forwards frame once it completely receives it
Application

32. IEEE Standards: Fast Ethernet
14 per network
Every 4 ip's
IEEE 802.3u
Switch forwards frame once it completely receives it

33. What is Layer 5 in the OSI Model?
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
2 - the bridge separates the collision domain
Frames
Session

34. How many Collision domains are there on a with 1 hub and 1 bridge 2 computers?
255.255.0.0
2 - the bridge separates the collision domain
IEEE 802.3u
Every 64 ip's

35. EIGRP: What is the default administrative distance?
14 per network
100
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
Switch forwards frame after receiving the 1st 64bytes to insure no errors.

36. EIGRP: What is the range of Autonomous System numbers?
30 per network
1-65535
Every 128 ip's
/22

37. What gets the clock rate - DCE or DTE?
DCE
Transport
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
Every 16 ip's

38. Rip Timers: How long is the default for Flush timer.
Periodic Updates of their routing table
Every 8 ip's
Router(config)#ip route {network address} {subnet-mask}
60

39. Subnetting: What is a /27 in Decimal
Router(config)#ip route {network address} {subnet-mask}
/28
255.255.255.224
IEEE 802.3ab

40. Symbol for EIGRP on a Show ip route
It adds the cost of each jump - R1 to R2 over a t1 is a cost of 64 - R2 to computer is a cost of 1. Total cost of route is 65
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE
D

41. What Layer does CDP operate at?
Layer 2
Packets
60
Every 4 ip's

42. Subnetting: What is a /30 in Decimal
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
255.255.255.252

43. What is Layer 7 in the OSI Model?
Application
By default - the flush timer is set for 240 seconds - which is 60 seconds longer than the invalid timer. When the flush timer expires - the route is removed from the routing table.
Switch forwards the frame as soon as it can
1. Router receives update from neighbor indicating a route down - Router makes route as down and starts holddown timer - If router gets an update indicating route is back holddown is removed - If an update is received indicating route is down again i

44. IEEE Standards: Gibabit Ethernet (Fibre)
IEEE 802.3z
Session
Switch forwards frame once it completely receives it
1-65535

45. What is Layer 1 in the OSI Model?
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
Switch forwards frame once it completely receives it
Physical
R

46. Subnetting: where do the networks break with a /30

47. What is the Network PDU called?
Data-Link
Frames
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
Packets

48. Rip: What is the command to enable Ripv2?
Every 16 ip's
/9
R1(config)#router rip - R1(config-router)#version 2
Router(config)#hostname R1 - R1(config)#line VTY 0 4 - R1(config-line)#login local - R1(config-line)#transport input telnet ssh - R1(config-line)#exit - R1(config)#username {user} password {pass} - R1(config)#ip domain-name {domainname} - R1(config)#

49. OSPF: What does OSPF use for its metric?
The metric is called cost - and refers to the speed of the port - IE 56kps = 1785 where Fast Ethernet = 1
120
Packets
R3(config)#router rip - R3(config-router)#network 192.168.1.2

50. Rip: Command to prevent rip updates on an interface
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE
/28
Bandwidth - Delay - reliability and Load