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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. How many Collision domains are there on a with 1 hub and 2 computers?
Router(config)#ip route {network address} {subnet-mask}
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
1 - everything hooked to the hub is in the same collision domain
Every 32 ip's

2. 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
Transport
R
Bandwidth - Delay - reliability and Load

3. What is the layer 2 PDU called?
Frames
Layer 2
2 hosts
126 per network

4. Subnetting: where do the networks break with a /28

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5. Command for a static route with 'Next Hop' Address
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
Router(config)#ip route {network address} {subnet-mask}
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)#
Every 8 ip's

6. Rip and EIGRP use what to keep other routers aware of their status?
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
Periodic Updates of their routing table
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change
Physical

7. Rip: how do hold down timers work?
30 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
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.
IEEE 802.3ab

8. What is Layer 5 in the OSI Model?
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
110
Session
255.255.192.0

9. What is the Network PDU called?
IEEE 802.3u
126 per network
Packets
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)

10. Switching Methods: What is Cut-through?
Data-Link
Switch forwards the frame as soon as it can
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.

11. IEEE Standards: Ethernet
1:G/W - 2:Green - 3:O/W - 4:Blue - 5:B/W - 6:Orange - 7:Brown/W - 8:Brown
R3(config)#router rip - R3(config-router)#network 192.168.1.2
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)#
IEEE 802.3

12. OSPF: how do you change the cost of an interface for OSPF?
Frames
Segments
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change
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.

13. EIGRP: How do you view if there are any successor routes?
Show ip eigrp topology
Every 16 ip's
Every 128 ip's
255.255.192.0

14. RIP: What Algorithm is used in RIP>
62 per network
Bellman-Ford
Every 8 ip's
Data-Link

15. What Layer does CDP operate at?
Layer 2
Closest multiple of the magic number that is not over the interesting octets number.
Bandwidth - Delay - reliability and Load
Network

16. EIGRP: What packet is used to propagate routing information?
Shortest path first - (SPF)
110
Closest multiple of the magic number that is not over the interesting octets number.
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet

17. Subnetting: What is a /27 in Decimal
Every 128 ip's
255.255.255.224
The metric is called cost - and refers to the speed of the port - IE 56kps = 1785 where Fast Ethernet = 1
DCE

18. OSPF: Commands to enable OSPF area 0 and advertise network 10.1.1.1 /28
Every 32 ip's
IEEE 802.3
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0

19. OSPF: How does OSPF calulate the cost of each route - to figure out which way to go?
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
R
Data-Link
Every 32 ip's

20. Subnetting: What is a /16 in Decimal
Presentation
IEEE 802.3u
255.255.0.0
Every 32 ip's

21. Switching Methods: What is Fragment-free?
Query and other router responds with a REPLY packet.
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
Switch forwards frame after receiving the 1st 64bytes to insure no errors.
The metric is called cost - and refers to the speed of the port - IE 56kps = 1785 where Fast Ethernet = 1

22. RIP: What is the default Administrative Distance?
Layer 2
Frames
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization
120

23. Rip: Command to prevent rip updates on an interface
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
DUAL: Difusing Update Algorithm
Periodic Updates of their routing table
Every 64 ip's

24. IEEE Standards: Fast Ethernet
Every 32 ip's
IEEE 802.3u
Router(config)#ip route {network address} {subnet-mask}
Router(config)# router rip - Router(config-router)# passive-interface fa0/0

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

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26. EIGRP: What packet is used to search for networks?
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
Query and other router responds with a REPLY packet.
Presentation
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

27. OSPF: What Algorithm is used?
Shortest path first - (SPF)
180
Layer 2
Every 8 ip's

28. Subnetting: How many hosts per network if the subnet mask is 255.255.255.252
Packets
2 hosts
Router(config)#ip route {exit-interface}
Session

29. Subnetting: How many hosts per network if the subnet mask is 255.255.255.128
126 per network
Shortest path first - (SPF)
IEEE 802.3z
255.255.0.0

30. Command for a static route with exit interface
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
R
Every 4 ip's
Router(config)#ip route {exit-interface}

31. Rip Timers: How long is the default for Flush timer.
60
/22
Every 8 ip's
110

32. What is the Transport PDU called?
Hop Count
Segments
/22
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

33. Subnetting: where do the networks break with a /29

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34. Subnetting: What is a 255.255.252.0 in prefix notation
IEEE 802.3
60
Network
/22

35. Switching Methods: What is Store and Forward?
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
Packets
1-65535
Switch forwards frame once it completely receives it

36. RIP Timers: What is an invalid Timer?
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical
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.
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
Packets

37. How do you find the magic number for subnetting?
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
Segments
180 seconds

38. Rip Timers: How long is the default for Invalid timer.
R
180 seconds
Session
100

39. Rip Timers: How long is the default for Holddown timer.
180
Switch forwards frame after receiving the 1st 64bytes to insure no errors.
Every 128 ip's
Router(config)# router rip - Router(config-router)# passive-interface fa0/0

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

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41. Subnetting: How many hosts per network if the subnet mask is 255.255.255.192
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)#
Router(config)#ip route {network address} {subnet-mask}
62 per network
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.

42. EIGRP: What is the range of Autonomous System numbers?
Closest multiple of the magic number that is not over the interesting octets number.
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
1-65535
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical

43. RIP: Commands to enable ripv1 on a router and add a route to 192.168.1.2
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)#
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization
R3(config)#router rip - R3(config-router)#network 192.168.1.2
DCE

44. Subnetting: How many hosts per network if the subnet mask is 255.255.255.240
Switch forwards frame once it completely receives it
2 hosts
14 per network
Pins 1+2 swap places with pins 3+6

45. Rip: What causes a triggered update?
D
100
180 seconds
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.

46. What is the layer 4 PDU called?
1:G/W - 2:Green - 3:O/W - 4:Blue - 5:B/W - 6:Orange - 7:Brown/W - 8:Brown
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
Network
Segments

47. What is the metric for RIP
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.
Bellman-Ford
14 per network
Hop Count

48. Subnetting: What is a 255.255.255.240 in prefix notation
IEEE 802.3
R1(config)#router rip - R1(config-router)#version 2
/28
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds

49. Using the magic number how to you figure the broadcast?
Add the magic number to the network minus 1
14 per network
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
Switch forwards frame after receiving the 1st 64bytes to insure no errors.

50. EIGRP: What is the hello packet used for?
Show ip eigrp topology
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
1 - everything hooked to the hub is in the same collision domain
2 - each port is it's own collision domain