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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: How does OSPF calulate the cost of each route - to figure out which way to go?
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK 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
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
Packets

2. OSPF: What is the process used by OSPF to build a routing table (step by step)
1-65535
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
14 per network

3. Subnetting: What is a /18 in Decimal
126 per network
255.255.192.0
Segments
Data-Link

4. Rip: What causes a triggered update?
180 seconds
Physical
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
Periodic Updates of their routing table

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

6. How do you find the magic number for subnetting?
255.255.255.224
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
/22
IEEE 802.3ab

7. What is the metric for EIGRP
Bandwidth - Delay - reliability and Load
/24
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
IEEE 802.3z

8. What is the layer 3 PDU called?
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 16 ip's
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.
Packets

9. What is the Data-Link PDU called?
Pins 1+2 swap places with pins 3+6
Frames
2 - the bridge separates the collision domain
Show ip eigrp topology

10. Switching Methods: What is Store and Forward?
126 per network
Switch forwards frame once it completely receives it
Router(config)#ip route {network address} {subnet-mask}
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

11. What is the Transport PDU called?
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
DUAL: Difusing Update Algorithm
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
Segments

12. Name the OSI Layers
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical
Presentation
1 - everything hooked to the hub is in the same collision domain
Segments

13. What is the layer 4 PDU called?
Segments
14 per network
R
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240

14. Command for a static route with 'Next Hop' Address
Router(config)#ip route {network address} {subnet-mask}
Hop Count
Every 128 ip's
R1(config)#router rip - R1(config-router)#version 2

15. What are the comands to set the clock rate in a serial connection?
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE
Switch forwards the frame as soon as it can
30 per network
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240

16. What is the Network PDU called?
R3(config)#router rip - R3(config-router)#network 192.168.1.2
62 per network
R
Packets

17. Subnetting: What is a 255.128.0.0 in prefix notation
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization
/9
Physical
2 hosts

18. EIGRP: What is the hello packet used for?
Hop Count
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
Every 64 ip's

19. What Layer does CDP operate at?
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.
Query and other router responds with a REPLY packet.
Layer 2
Every 32 ip's

20. Subnetting: What is a /27 in Decimal
Hop Count
255.255.255.224
Data-Link
Every 32 ip's

21. 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
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
2 - each port is it's own collision domain
Segments

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

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

24. What are the commands to setup SSH?
180 seconds
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
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)#

25. What gets the clock rate - DCE or DTE?
2 - each port is it's own collision domain
DCE
Hop Count
Segments

26. RIP Timers: What is an Flush Timer?
IEEE 802.3z
DUAL: Difusing Update Algorithm
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.

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

28. RIP: What is the default Administrative Distance?
Application
120
Closest multiple of the magic number that is not over the interesting octets number.
DCE

29. Subnetting: What is a 255.255.252.0 in prefix notation
126 per network
/22
2 hosts
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE

30. What is the layer 2 PDU called?
Layer 2
Frames
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
DCE

31. What is Layer 5 in the OSI Model?
Session
Every 8 ip's
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
Every 4 ip's

32. Symbol for Rip on a Show ip route
Data-Link
R
Frames
2 - the bridge separates the collision domain

33. Symbol for EIGRP on a Show ip route
Every 8 ip's
D
IEEE 802.3z
Network

34. RIP Timers: What is an invalid Timer?
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.
Frames
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)
/9

35. Rip: What is the command to enable Ripv2?
R1(config)#router rip - R1(config-router)#version 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
60
Switch forwards frame once it completely receives it

36. Subnetting: How many hosts per network if the subnet mask is 255.255.255.240
Every 4 ip's
14 per network
2 - each port is it's own collision domain
Transport

37. What is Layer 6 in the OSI Model?
180 seconds
2 - each port is it's own 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.
Presentation

38. What is the metric for RIP
Hop Count
Physical
2 hosts
Router(config)#ip route {network address} {subnet-mask}

39. EIGRP: What is the range of Autonomous System numbers?
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
180
255.255.192.0
1-65535

40. IEEE Standards: Gibabit Ethernet (Fibre)
Router(config)#ip route {exit-interface}
DUAL: Difusing Update Algorithm
IEEE 802.3z
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)

41. OSPF: What is the default administrative distance?
Data-Link
110
Transport
2 - the bridge separates the collision domain

42. IEEE Standards: Gibabit Ethernet (Copper)
255.255.255.128
IEEE 802.3ab
DUAL: Difusing Update Algorithm
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization

43. Rip and EIGRP use what to keep other routers aware of their status?
Transport
DUAL: Difusing Update Algorithm
IEEE 802.3z
Periodic Updates of their routing table

44. Rip: how do hold down timers work?
Every 128 ip's
Switch forwards frame once it completely receives it
Data-Link
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

45. 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
Every 4 ip's
/28
Router(config)#ip route {network address} {subnet-mask}

46. What is Layer 2 in the OSI Model?
2 - each port is it's own collision domain
Every 4 ip's
Data-Link
Layer 2

47. What is Layer 3 in the OSI Model?
Network
/24
Segments
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical

48. IEEE Standards: Fast Ethernet
IEEE 802.3u
255.255.255.128
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
IEEE 802.3ab

49. Subnetting: How many hosts per network if the subnet mask is 255.255.255.224
DCE
30 per network
Switch forwards the frame as soon as it can
180

50. Subnetting: What is a /16 in Decimal
IEEE 802.3z
Router(config)#ip route {exit-interface}
255.255.0.0
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