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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. Name the OSI Layers
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical

2. Rip: What is the command to enable Ripv2?
Layer 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)#
R1(config)#router rip - R1(config-router)#version 2
Session

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

4. EIGRP: What packet is used to propagate routing information?
Physical
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
Every 128 ip's
Router(config)# router rip - Router(config-router)# passive-interface fa0/0

5. EIGRP: How do you view if there are any successor routes?
Show ip eigrp topology
1 - everything hooked to the hub is in the same collision domain
120
R

6. Rip: What does v2 have that v1 does not?
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
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 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

7. IEEE Standards: Fast Ethernet
2 hosts
IEEE 802.3u
180 seconds
Session

8. OSPF: What is the process used by OSPF to build a routing table (step by step)
2 hosts
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
1:O/W - 2:Orange - 3:G/W - 4:Blue - 5:B/W - 6:Green - 7:Brown/W - 8:Brown
180

9. OSPF: What does OSPF use for its metric?
255.255.192.0
Every 32 ip's
R3(config)#router rip - R3(config-router)#network 192.168.1.2
The metric is called cost - and refers to the speed of the port - IE 56kps = 1785 where Fast Ethernet = 1

10. EIGRP: What is the range of Autonomous System numbers?
255.255.192.0
1:O/W - 2:Orange - 3:G/W - 4:Blue - 5:B/W - 6:Green - 7:Brown/W - 8:Brown
1-65535
Show ip eigrp topology

11. Subnetting: How many hosts per network if the subnet mask is 255.255.255.252
Physical
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization
2 hosts
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.

12. Subnetting: What is a /16 in Decimal
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
255.255.0.0
Bandwidth - Delay - reliability and Load
Periodic Updates of their routing table

13. What is the metric for EIGRP
Bandwidth - Delay - reliability and Load
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
DCE
126 per network

14. What is the Network PDU called?
255.255.192.0
Presentation
Packets
30 per network

15. Rip Timers: How long is the default for Holddown timer.
Segments
180
14 per network
IEEE 802.3ab

16. RIP: What is the default Administrative Distance?
255.255.0.0
IEEE 802.3ab
120
/22

17. IEEE Standards: Ethernet
IEEE 802.3
255.255.255.224
IEEE 802.3u
DCE

18. Rip: What causes a triggered update?
255.255.0.0
Pins 1+2 swap places with pins 3+6
126 per network
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.

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

20. Using the magic number how to you figure the broadcast?
/22
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
Add the magic number to the network minus 1
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)#

21. Command for a static route with 'Next Hop' Address
Closest multiple of the magic number that is not over the interesting octets number.
Router(config)#ip route {network address} {subnet-mask}
255.255.255.128
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0

22. What is Layer 6 in the OSI Model?
DUAL: Difusing Update Algorithm
Packets
Presentation
Switch forwards frame after receiving the 1st 64bytes to insure no errors.

23. What is Layer 1 in the OSI Model?
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.
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
Session

24. What is the boot sequence for Cisco Routers?
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)
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)#
Application

25. IEEE Standards: Gibabit Ethernet (Copper)
IEEE 802.3ab
Session
Hop Count
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

26. Subnetting: What is a /27 in Decimal
255.255.255.224
Frames
Query and other router responds with a REPLY packet.
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization

27. What is Layer 2 in the OSI Model?
255.255.0.0
Data-Link
Add the magic number to the network minus 1
Packets

28. Subnetting: What is a 255.128.0.0 in prefix notation
255.255.255.128
/9
D
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical

29. Using the magic number how to you figure the network?
Network
Segments
Packets
Closest multiple of the magic number that is not over the interesting octets number.

30. OSPF: how do you change the cost of an interface for OSPF?
62 per network
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change
IEEE 802.3
Transport

31. Rip and EIGRP use what to keep other routers aware of their status?
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
Periodic Updates of their routing table
255.255.255.128
D

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

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

34. What is the layer 2 PDU called?
Frames
Segments
Every 64 ip's
/22

35. Rip Timers: How long is the default for Invalid timer.
/28
IEEE 802.3u
180 seconds
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE

36. Subnetting: How many hosts per network if the subnet mask is 255.255.255.240
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)
Bandwidth - Delay - reliability and Load
14 per network

37. What is the Data-Link PDU called?
Frames
180
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
Packets

38. What is the layer 3 PDU called?
Packets
IEEE 802.3
/9
110

39. Command for a static route with exit interface
Application
Pins 1+2 swap places with pins 3+6
IEEE 802.3ab
Router(config)#ip route {exit-interface}

40. Symbol for EIGRP on a Show ip route
/9
180
D
The metric is called cost - and refers to the speed of the port - IE 56kps = 1785 where Fast Ethernet = 1

41. What is Layer 4 in the OSI Model?
Transport
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
Query and other router responds with a REPLY packet.
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

42. How do you find the magic number for subnetting?
Transport
Shortest path first - (SPF)
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240

43. Switching Methods: What is Cut-through?
Switch forwards the frame as soon as it can
/9
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
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.

44. Subnetting: How many hosts per network if the subnet mask is 255.255.255.224
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
IEEE 802.3ab
255.255.255.252
30 per network

45. CABLES: What is the difference between T568A and T568B?
30 per network
/24
Pins 1+2 swap places with pins 3+6
Bellman-Ford

46. Rip Timers: How long is the default for Flush timer.
255.255.0.0
60
Switch forwards frame once it completely receives it
R3(config)#router rip - R3(config-router)#network 192.168.1.2

47. CABLES: What is the T568A Pinout Standard?
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.
DUAL: Difusing Update Algorithm
1:G/W - 2:Green - 3:O/W - 4:Blue - 5:B/W - 6:Orange - 7:Brown/W - 8:Brown
Add the magic number to the network minus 1

48. What is the metric for RIP
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
Every 32 ip's
Hop Count
2 hosts

49. What is Layer 5 in the OSI Model?
Presentation
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
Session
Segments

50. OSPF: How does OSPF calulate the cost of each route - to figure out which way to go?
120
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
R3(config)#router rip - R3(config-router)#network 192.168.1.2
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization