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: How long is the default for Invalid timer.
Every 16 ip's
180 seconds
Segments
Segments


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


3. Subnetting: What is a 255.128.0.0 in prefix notation
/9
Frames
Segments
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.


4. 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
Router(config)#ip route {exit-interface}
Transport
Data-Link


5. EIGRP: What packet is used to propagate routing information?
256 - the interesting (non-255/0) number. IE: 255.240.0.0 the interesting number is 240
IEEE 802.3
Application
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet


6. Subnetting: What is a /27 in Decimal
Application
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)
255.255.255.224
The metric is called cost - and refers to the speed of the port - IE 56kps = 1785 where Fast Ethernet = 1


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


8. RIP: What is the default Administrative Distance?
(5)Application - (4)Transport - (3)Internet - (2)Data-Link - (1)Physical
14 per network
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
120


9. Rip: What causes a triggered update?
DUAL: Difusing Update Algorithm
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.
110
30 per network


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


11. IEEE Standards: Fast Ethernet
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE
255.255.192.0
IEEE 802.3u
255.255.255.128


12. Rip: What does v2 have that v1 does not?
Bellman-Ford
255.255.192.0
Includes sub-net mask in updates making it classless - has authentication - supports variable length subnet mask - uses multicast instead of broadcast - supports manual summarization
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


13. Subnetting: How many hosts per network if the subnet mask is 255.255.255.128
Every 32 ip's
126 per network
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)
Transport


14. EIGRP: What is the commands to enable EIGRP for autonomous area 7 and to route network 192.168.1.0 /30
Periodic Updates of their routing table
Switch forwards frame once it completely receives it
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
255.255.255.252


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


16. IEEE Standards: Gibabit Ethernet (Fibre)
R3(config)#router rip - R3(config-router)#network 192.168.1.2
IEEE 802.3z
/24
Packets


17. Subnetting: What is a 255.255.255.0 in prefix notation
2 - the bridge separates the collision domain
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
/24
Data-Link


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


19. Subnetting: What is a /16 in Decimal
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)#
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
255.255.0.0
Switch forwards the frame as soon as it can


20. CABLES: What is the difference between T568A and T568B?
R1(config)#router eigrp 7 - R1(config-router)#network 192.168.1.0 0.0.0.3
Pins 1+2 swap places with pins 3+6
60
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. What are the comands to set the clock rate in a serial connection?
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
The metric is called cost - and refers to the speed of the port - IE 56kps = 1785 where Fast Ethernet = 1
1 - everything hooked to the hub is in the same collision domain
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE


22. OSPF: What is the process used by OSPF to build a routing table (step by step)
30 per network
Frames
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database
255.255.255.128


23. Rip: Command to prevent rip updates on an interface
Closest multiple of the magic number that is not over the interesting octets number.
255.255.255.224
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
Application


24. Using the magic number how to you figure the network?
126 per network
Every 8 ip's
Closest multiple of the magic number that is not over the interesting octets number.
255.255.255.252


25. EIGRP: What packet is used to search for networks?
Hop Count
Query and other router responds with a REPLY packet.
30 per network
Show ip eigrp topology


26. What is Layer 7 in the OSI Model?
60
Closest multiple of the magic number that is not over the interesting octets number.
Application
Interface changes state (up/down) - A route has entered or exited the unreachable state - a route was installed in the routing table.


27. 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.
Switch forwards frame after receiving the 1st 64bytes to insure no errors.
Hop Count
255.255.255.224


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


29. OSPF: Commands to enable OSPF area 0 and advertise network 10.1.1.1 /28
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.
R1(config)# router OSPF 1 - R1(config-router)#network 10.1.1.0 0.0.0.15 area 0
Bandwidth - Delay - reliability and Load
2 - the bridge separates the collision domain


30. What is the Network PDU called?
Hop Count
2 hosts
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)#
Packets


31. What gets the clock rate - DCE or DTE?
DCE
Packets
D
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE


32. IEEE Standards: Gibabit Ethernet (Copper)
IEEE 802.3ab
Router(config)#ip route {exit-interface}
Network
Closest multiple of the magic number that is not over the interesting octets number.


33. What is the metric for EIGRP
Every 32 ip's
100
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
Bandwidth - Delay - reliability and Load


34. What is the metric for RIP
Can be multicast or unicast depending on number of routers - Update packets. Responds with an ACK packet
Hop Count
R1(config)#router rip - R1(config-router)#version 2
Frames


35. What is Layer 2 in the OSI Model?
255.255.255.128
Data-Link
Every 32 ip's
Router(config)#ip route {exit-interface}


36. EIGRP: What is the hello packet used for?
Every 8 ip's
Router(config)# router rip - Router(config-router)# passive-interface fa0/0
Multicast packet used for discovery of neighbors sent every 5 seconds - on WAN links sent every 60 seconds
120


37. CABLES: What is the T568A Pinout Standard?
Closest multiple of the magic number that is not over the interesting octets number.
Pins 1+2 swap places with pins 3+6
1:G/W - 2:Green - 3:O/W - 4:Blue - 5:B/W - 6:Orange - 7:Brown/W - 8:Brown
IEEE 802.3z


38. Subnetting: What is a /30 in Decimal
255.255.255.252
1. NVRAM - 2. Flash (sequential) - 3. TFTP server (network boot) - 4. ROM (partial IOS)
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:O/W - 2:Orange - 3:G/W - 4:Blue - 5:B/W - 6:Green - 7:Brown/W - 8:Brown


39. What is Layer 3 in the OSI Model?
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
Presentation
Switch forwards frame after receiving the 1st 64bytes to insure no errors.
Network


40. RIP Timers: What is an Flush Timer?
Router(config)#ip route {network address} {subnet-mask}
Every 64 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.
DUAL: Difusing Update Algorithm


41. What is the Data-Link PDU called?
Router(config)#ip route {network address} {subnet-mask}
60
Frames
180


42. IEEE Standards: Ethernet
Every 8 ip's
60
Frames
IEEE 802.3


43. RIP Timers: What is an Holddown Timer?
/28
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
Transport
180


44. What is Layer 5 in the OSI Model?
Data-Link
1:G/W - 2:Green - 3:O/W - 4:Blue - 5:B/W - 6:Orange - 7:Brown/W - 8:Brown
Session
Segments


45. Subnetting: What is a /25 in Decimal
255.255.255.128
14 per network
255.255.192.0
126 per network


46. RIP: Commands to enable ripv1 on a router and add a route to 192.168.1.2
R1(config)#int s0/0 - R1(config-inf)clock rate 64000 <-- on the DCE
R3(config)#router rip - R3(config-router)#network 192.168.1.2
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.
1. Discovery packets - LSP built containing the state of each link - Flood LSP to neighbors - Build Link-state database


47. Subnetting: How many hosts per network if the subnet mask is 255.255.255.252
Data-Link
/22
2 hosts
DCE


48. What Layer does CDP operate at?
(7)Application -(6)Presentation -(5)Session -(4)Transport - (3)Network - (2)Data Link - (1)Physical
1 - everything hooked to the hub is in the same collision domain
Layer 2
180 seconds


49. Symbol for Rip on a Show ip route
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.
Every 64 ip's
R
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


50. Rip and EIGRP use what to keep other routers aware of their status?
180 seconds
Periodic Updates of their routing table
/22
Bandwidth - Delay - reliability and Load