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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. OSPF: What is the process used by OSPF to build a routing table (step by step)
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
120
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
Application

2. Rip: What is the command to enable Ripv2?
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization
R1(config)#router rip - R1(config-router)#version 2
Every 32 ip's
120

3. What is Layer 1 in the OSI Model?
/9
Physical
126 per network
R3(config)#router rip - R3(config-router)#network 192.168.1.2

4. OSPF: What is the default administrative distance?
110
Every 128 ip's
Every 64 ip's
Switch forwards frame after receiving the 1st 64bytes to insure no errors.

5. Switching Methods: What is Store and Forward?
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE
Switch forwards frame once it completely receives it
180 seconds
Segments

6. What is the metric for RIP
62 per network
Router(config)#ip route {exit-interface}
Hop Count
Application

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

8. Symbol for Rip on a Show ip route
Add the magic number to the network minus 1
Application
R
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

9. What is Layer 3 in the OSI Model?
Network
Hop Count
Packets
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical

10. Switching Methods: What is Cut-through?
/24
Periodic Updates of their routing table
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
Switch forwards the frame as soon as it can

11. Subnetting: What is a 255.255.252.0 in prefix notation
D
/22
Data-Link
Segments

12. Subnetting: What is a 255.255.255.0 in prefix notation
Every 4 ip's
Every 8 ip's
180 seconds
/24

13. Subnetting: How many hosts per network if the subnet mask is 255.255.255.252
Every 128 ip's
2 hosts
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

14. OSPF: how do you change the cost of an interface for OSPF?
Add the magic number to the network minus 1
R3(config)#router rip - R3(config-router)#network 192.168.1.2
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change

15. Subnetting: What is a 255.128.0.0 in prefix notation
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE
/9
/28
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds

16. RIP Timers: What is an Holddown Timer?
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
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.
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
Shortest path first - (SPF)

17. RIP: What is the default Administrative Distance?
Segments
IEEE 802.3u
Pins 1+2 swap places with pins 3+6
120

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

19. RIP Timers: What is an Flush Timer?
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.
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
/9
IEEE 802.3ab

20. Rip and EIGRP use what to keep other routers aware of their status?
110
Every 128 ip's
Periodic Updates of their routing table
Hop Count

21. What is Layer 5 in the OSI Model?
Session
100
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
255.255.255.252

22. Switching Methods: What is Fragment-free?
Switch forwards frame after receiving the 1st 64bytes to insure no errors.
IEEE 802.3ab
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
1 - everything hooked to the hub is in the same collision domain

23. What is the metric for EIGRP
Bandwidth - Delay - reliability and Load
/28
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.
IEEE 802.3u

24. EIGRP: What is the name of the algorithm used for EIGRP?
DUAL: Difusing Update Algorithm
Presentation
2 hosts
Every 128 ip's

25. What gets the clock rate - DCE or DTE?
DCE
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
14 per network
Bellman-Ford

26. What is the Data-Link PDU called?
Frames
Query and other router responds with a REPLY packet.
255.255.192.0
Closest multiple of the magic number that is not over the interesting octets number.

27. What is the layer 3 PDU called?
Packets
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical
Shortest path first - (SPF)
Periodic Updates of their routing table

28. 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.
/24
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical
Query and other router responds with a REPLY packet.

29. Command for a static route with 'Next Hop' Address
/24
Segments
Router(config)#ip route {network address} {subnet-mask}
Periodic Updates of their routing table

30. What is Layer 7 in the OSI Model?
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
Application
/9
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)

31. Rip Timers: How long is the default for Invalid timer.
180 seconds
255.255.255.252
Pins 1+2 swap places with pins 3+6
Data-Link

32. What is Layer 4 in the OSI Model?
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
Router(config)#ip route {network address} {subnet-mask}
180
Transport

33. Subnetting: What is a 255.255.255.240 in prefix notation
Bellman-Ford
IEEE 802.3z
2 - each port is it's own collision domain
/28

34. Subnetting: How many hosts per network if the subnet mask is 255.255.255.240
Segments
62 per network
14 per network
60

35. What is the Transport PDU called?
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
Frames
2 - each port is it's own collision domain
Segments

36. Subnetting: where do the networks break with a /27

37. Rip: What causes a triggered update?
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change
IEEE 802.3z
/9

38. Subnetting: What is a /27 in Decimal
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
255.255.255.224
Query and other router responds with a REPLY packet.

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

40. Command for a static route with exit interface
255.255.255.224
Router(config)#ip route {exit-interface}
Router(config)#ip route {network address} {subnet-mask}
Packets

41. OSPF: How does OSPF calulate the cost of each route - to figure out which way to go?
/24
Switch forwards the frame as soon as it can
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
Packets

42. IEEE Standards: Ethernet
Every 128 ip's
IEEE 802.3
60
/9

43. OSPF: Commands to enable OSPF area 0 and advertise network 10.1.1.1 /28
Every 16 ip's
Layer 2
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
255.255.255.252

44. What is the Network PDU called?
Packets
14 per network
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
Application

45. Subnetting: What is a /18 in Decimal
255.255.192.0
Pins 1+2 swap places with pins 3+6
Every 64 ip's
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical

46. Rip: Command to prevent rip updates on an interface
Every 4 ip's
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
Frames
Presentation

47. What is the layer 4 PDU called?
Segments
Layer 2
2 - the bridge separates the collision domain
1-65535

48. Using the magic number how to you figure the broadcast?
Add the magic number to the network minus 1
IEEE 802.3z
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical
Frames

49. How do you find the magic number for subnetting?
Frames
Shortest path first - (SPF)
Network
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240

50. Subnetting: How many hosts per network if the subnet mask is 255.255.255.128
2 - the bridge separates the collision domain
126 per network
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
Every 16 ip's