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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. 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
Network
255.255.255.128
Router(config)#ip route {network address} {subnet-mask}

2. Subnetting: How many hosts per network if the subnet mask is 255.255.255.240
/24
IEEE 802.3
14 per network
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3

3. Rip: Command to prevent rip updates on an interface
Switch forwards frame once it completely receives it
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
Data-Link

4. IEEE Standards: Ethernet
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 802.3
Show ip eigrp topology
Session

5. How many Collision domains are there on a with 1 hub and 2 computers?
2 - each port is it's own collision domain
/28
1 - everything hooked to the hub is in the same collision domain
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.

6. 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
Segments
Closest multiple of the magic number that is not over the interesting octets number.
255.255.255.224

7. EIGRP: What packet is used to propagate routing information?
126 per network
Every 128 ip's
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.

8. IEEE Standards: Gibabit Ethernet (Copper)
Every 64 ip's
Periodic Updates of their routing table
IEEE 802.3ab
Frames

9. OSPF: How does OSPF calulate the cost of each route - to figure out which way to go?
2 - each port is it's own collision domain
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
/24
Frames

10. Rip and EIGRP use what to keep other routers aware of their status?
180 seconds
Periodic Updates of their routing table
Segments
Presentation

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

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12. What gets the clock rate - DCE or DTE?
/9
Switch forwards the frame as soon as it can
Segments
DCE

13. Subnetting: What is a 255.255.255.0 in prefix notation
Segments
2 - each port is it's own collision domain
Query and other router responds with a REPLY packet.
/24

14. Command for a static route with 'Next Hop' Address
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE
255.255.255.252
Router(config)#ip route {network address} {subnet-mask}
Transport

15. OSPF: What Algorithm is used?
Shortest path first - (SPF)
180 seconds
/24
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical

16. OSPF: What is the default administrative distance?
110
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)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical
60

17. What is the boot sequence for Cisco Routers?
/9
D
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)
Pins 1+2 swap places with pins 3+6

18. What is Layer 1 in the OSI Model?
30 per network
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the 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.
Physical

19. OSPF: how do you change the cost of an interface for OSPF?
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change
Switch forwards the frame as soon as it can
/24
110

20. Rip Timers: How long is the default for Holddown timer.
180
Application
/9
255.255.255.252

21. Subnetting: How many hosts per network if the subnet mask is 255.255.255.128
D
126 per network
30 per network
Every 16 ip's

22. IEEE Standards: Gibabit Ethernet (Fibre)
IEEE 802.3
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
Shortest path first - (SPF)
IEEE 802.3z

23. Subnetting: How many hosts per network if the subnet mask is 255.255.255.192
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
2 hosts
Segments
62 per network

24. What is Layer 6 in the OSI Model?
Every 8 ip's
/9
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
Presentation

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

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26. Using the magic number how to you figure the broadcast?
Every 8 ip's
Transport
Add the magic number to the network minus 1
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.

27. Subnetting: What is a 255.255.255.240 in prefix notation
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.
/28
Physical
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0

28. Symbol for Rip on a Show ip route
Every 128 ip's
255.255.255.224
R
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet

29. Subnetting: What is a /27 in Decimal
Transport
Frames
255.255.255.224
Frames

30. 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.
Presentation
IEEE 802.3u
110

31. Subnetting: How many hosts per network if the subnet mask is 255.255.255.252
2 hosts
D
Transport
Switch forwards frame after receiving the 1st 64bytes to insure no errors.

32. What is the layer 4 PDU called?
Network
Segments
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.
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. CABLES: What is the T568A Pinout Standard?
255.255.0.0
Periodic Updates of their routing table
1:G/W - 2:Green - 3:O/W - 4:Blue - 5:B/W - 6:Orange - 7:Brown/W - 8:Brown
Hop Count

34. What is the layer 3 PDU called?
100
Segments
Packets
Switch forwards frame after receiving the 1st 64bytes to insure no errors.

35. EIGRP: What is the name of the algorithm used for EIGRP?
DUAL: Difusing Update Algorithm
255.255.255.252
The metric is called cost - and refers to the speed of the port - IE 56kps = 1785 where Fast Ethernet = 1
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.

36. RIP Timers: What is an invalid Timer?
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
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.
Packets
Packets

37. RIP: What Algorithm is used in RIP>
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
Bellman-Ford
DCE
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)#

38. Subnetting: What is a 255.255.252.0 in prefix notation
Bellman-Ford
/22
DCE
Every 8 ip's

39. Subnetting: How many hosts per network if the subnet mask is 255.255.255.224
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change
DCE
Presentation
30 per network

40. Rip: What does v2 have that v1 does not?
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
Every 16 ip's
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization
Bandwidth - Delay - reliability and Load

41. What is the Network PDU called?
Bellman-Ford
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
Packets

42. IEEE Standards: Fast Ethernet
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
IEEE 802.3u
120
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database

43. What is Layer 2 in the OSI Model?
Segments
Switch forwards frame once it completely receives it
255.255.255.252
Data-Link

44. OSPF: Commands to enable OSPF area 0 and advertise network 10.1.1.1 /28
R
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
Switch forwards frame after receiving the 1st 64bytes to insure no errors.
255.255.0.0

45. Rip: how do hold down timers work?
120
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
Every 128 ip's
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.

46. EIGRP: What is the commands to enable EIGRP for autonomous area 7 and to route network 192.168.1.0 /30
Packets
Segments
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
Every 4 ip's

47. What Layer does CDP operate at?
Closest multiple of the magic number that is not over the interesting octets number.
Layer 2
Use command bandwidth {bandwidth in KPS} or the command ip ospf cost {amount} both in the interface you want to change
Transport

48. What is the metric for RIP
Every 16 ip's
255.255.0.0
Hop Count
Switch forwards the frame as soon as it can

49. EIGRP: What is the hello packet used for?
2 - the bridge separates the collision domain
Add the magic number to the network minus 1
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds

50. Rip: What is the command to enable Ripv2?
IEEE 802.3ab
/22
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