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CCNP Switch Deck

Instructions:

Answer 50 questions in 15 minutes.
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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 are BDPUs spread?
The total delay from start to finish
The port is forced to always authorize any connected client with no authentication necessary (default)
Multicast to 01-80-c2-00-00-00
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology

2. RSTP designated port
Connects with SONET or SDH
Either desirable or auto mode
1-LAP gets a DHCP address - 2-LAP learns IP of available WLC - 3-LAP sends a join request to WLC and receives join reply - 4-WLC sends code image - if necessary - 5-Tunnels are created
Port with best root path cost on segment

3. What are the 3 RSTP port types?
Needs hardware upgrade over WEP - uses AES encryption
LACP port priority
Control functions
Edge - root - and point to point

4. What does VTP do?
Manages addition - deletion and renaming VLANs across the network
26-byte header - 4-byte trailer with CRC
If any BDUP is received on a port - it puts the port into the errdisable state
Checks the destination MAC in the header against the target MAC in the ARP reply

5. How does adding option-82 to DHCP snooping affect things?

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6. What is a punt adjacency?
802.1D
LWAPP (Cisco proprietary) and CAP-WAP (standards based)
Packets must be sent to the L3 engine for further processing
Should be used on access switches - can't be used on root - keeps enabled switch from becoming root by raising priority of switch and all ports - making them undesirable

7. What is DSCP codepoint EF(46)?
Differentiated services code point
Per VLAN
900 MHz - 2.4Ghz - and 5-6GHz
Critical...used most often for IPT

8. What is a CEF punt?

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9. What are the steps of RSTP convergence?
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec
Globally
If the switch or the powered device doesn't suport power class discovery
1- root bridge is elected - 2-the state of eery switch port in the STP domain must be brought from blocking state to the appropriate state

10. What are the 3 redundant supervisor modes?
RPR - RPR+ - and SSO
Data goes over native vlan - voice goes over specified VLAN - voice QOS is 802.1p
The time that a port spends in both listening and learning states . Default 15 seconds
1- inferior BDPU on blocked-considered alternative - 2-inferior on root-all blocked ports considered alternate - 3-if inferior arrives on root and no blocked ports - assumes loss of connectivity to root

11. Define GLBP
Stateful switchover - redundant sup is fully booted and init'd. Both start and run config are synched as is L2 information - and switchinterfaces.
Gateway load balancing protocol - cisco proprietary
Show standby
All L2 connectivity should be contained within the access layer.

12. What ILP mode are all ports in by default?
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
Auto mode
Trunk

13. What can cause a wireless client to switch between Aps?
The total delay from start to finish
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
Immediate (class 2)
Control functions

14. How does DAI work?
All ARP packets that arrive on untrusted ports are inspected.
By default weight is 100. Can be made dynamic per interface
1-1005 (1 and 1002-1005 are reserved)
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz

15. Define HSRP
Port stays up - packets from violating MACs dropped - no logging
The port asks the other end to trunk
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
Can send and receive BDPUs

16. What does the skinny protocol do?
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
Transmits keystrokes from phone and commands from CCM
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds

17. What are 2 ways to configure VLAN and VTP information?
Multicast to 01-80-c2-00-00-00
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy
4
2

18. What is the STP learning state?
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
Roughly 50%
After forwarding delay - port can learn new MAC addresses
Local only

19. What is the default network diameter?
7 switches from root bridge
Yes
It is enabled by default on all CEF capable switches
Use the spanning-tree root macro

20. What is a PVLAN?
Data and voice over native vlan - no QOS but still uses 802.1p trunk
0000.5e00.01xx
Packets are discarded due to an ACL or policy action
A private VLAN can be logically associated with a special secondary vlan

21. unknown unicast flooding
Those that connect to other switches
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
Half-duplex
MAC addresses are learned from the source MAC of incoming frames. If the destination address is unknown - the frame is flooded out all except the receiving port.

22. What is RPVST+?
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive
If any BDUP is received on a port - it puts the port into the errdisable state
2 strand MMF with MT-RJ or SC connectors
The total delay from start to finish

23. If a wireless station needs to transmit and another device is transmitting - what happens?
All ARP packets that arrive on untrusted ports are inspected.
The MST instance (MSTI) runs alongside the IST and represents an STP instance
The total delay from start to finish
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting

24. What is 802.1x force-authorized?
Between any type of interface as long as the interface can have an L3 address assigned
The L3 forwarding engine can't forward the packet in hardware because there is no L2 next-hop address - so the packet is sent to the L3 engine to generate the ARP response
1 IP subnet
The port is forced to always authorize any connected client with no authentication necessary (default)

25. How much BW does a voip connection use?
CEF is distributed completely among multiple L3 forwarding engines.
The active router. All other routers are in backup state
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
12 kbps with headers and compression

26. Where is UDLD enabled?
Used when ACLs specify port ranges...used by TCAM
A host port goes up or down
Port that connects to another switch and becomes a designated port
All fiber-optic links between switches (must be enabled on both ends)

27. How doed backbonefast work?
0-255
Multicast to 01-80-c2-00-00-00
That they aren't using the same frequencies.
By short-circuiting the max age timer

28. What are the steps to configure MST?
1- enable MST - 2-enter MST config mode - 3-assign region name and region configuration rev - 4-map vlans to an MSTI - 5-show pending changes - 6- commit by exiting
As a VLAN access map
0000.5e00.01xx
The time that a port spends in both listening and learning states . Default 15 seconds

29. What are the 2 power over ethernet methods?
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
Cisco ILP and 802.3af
Globally
Differentiated services code point

30. WEP encryption
Sends a voltage across the receive pairs to detect a 25k ohm resistance
Between any type of interface as long as the interface can have an L3 address assigned
Weak key rotation
Admin down

31. What is a topology change?
When a port moves into forwarding or from fowarding or learning to blocking.
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
5 classes with 3 drop precedences
A private VLAN can be logically associated with a special secondary vlan

32. How many 802.3af power classes are there?
Used when there are 1 or more VLANs mapped to a single STP instance
1500B
5 (0-4 with 4 being the highest)
All nondesignated ports - but ok for all ports

33. How is a QoS trust bondary configured?
Root - designated - blocking - alternate - forwarding (host)
Two distribution switches that aggregate one or more access switches
Every switch and router in a network must be configured with appropriate QoS features and policies
10-15%

34. What is DAI?
Dynamic arp inspection
Half-duplex
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each

35. What is the STP forward delay timer?
Every switch and router in a network must be configured with appropriate QoS features and policies
Only when a nonedge port transitions to forwarding
The time that a port spends in both listening and learning states . Default 15 seconds
Up to 4 can be used in a group. Called active virtual forwarders (AVF)

36. What is RPR+?

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37. What does MSTP do?
FE and GE
Used when there are 1 or more VLANs mapped to a single STP instance
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
Time between BDPUs sent by root bridge. Default of 2 seconds

38. On what scope is DAI enabled?
SC fiber or RJ-45
L2
Per VLAN
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p

39. What is a wall wart?
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance
An ac adaptor that plugs into a wall outlet.
Via an 802.1Q trunk or a single VLAN access port
Regions and instances

40. What is backbonefast?
Distribution layer
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
Connects with SONET or SDH
Roughly 50%

41. By default - what submode does PAgP operate in with the desirable and auto modes?
Silent
Used when ACLs specify port ranges...used by TCAM
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
After forwarding delay - port can learn new MAC addresses

42. Where does layer switching occur?
Checks the sender's ip in all arp requests and checks the sender's IP against target IP in all replies
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
Between any type of interface as long as the interface can have an L3 address assigned
If a unidirectional link is detected - the switch doesn't try to reestablish the link. ULD msgs are sent once/sec for 8 seconds - then the port is err-disabled

43. Where shoul dmultilayer switches be implemented?
The port will operate under 802.1D rules. If they are received on the same port - it will run 802.1D until the migration delay expires
Distribution layer
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
When the size of a cell is intentionally reduced

44. 802.11g
Plain text or md5
RADIUS
Half-duplex
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz

45. What is 802.1x auto?
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
Almost eliminates listening and learning states for single hosts on an access link
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
1 second. Backup routers can learn the interval from the master

46. How are VACLs applied
0007.b4xx.xxyy where xx.xx is six 0 bits followed by a 10-bit GLBP group numberr. Yyyy is the virtual forwarder number
To a VLAN and not to a VLAN interface (SVI)
The same as a standby group in HSRP
The station can transmit immediately and wait for an ack

47. What is a community secondary VLAN?
A VLAN that spans the entire fabric
If the client maintains the same IP address as it roams between Aps. All must have same VLAN - SSID - and subnet
Hosts within a secondary can communicate with each other and with the primary - but not with another secondary vlan
Checks the source MAC in the header against the sender MAC in the ARP reply

48. How do you prevent switch spoofing?
Prevents the dhcp binding DB from being checked.
FE and GE
By configuring every switch port to have an expected and controlled behavior
If the client maintains the same IP address as it roams between Aps. All must have same VLAN - SSID - and subnet

49. What is DSCP codepoint AF31(26)?
During the time that the FIB entry is in CEF glean waiting for ARP entries - subsequent packet to that host are dropped to keep input queues from filling
Use sh interface on the interface and look for error counts > 10
Flash (class 3)
2 - one for control messages and one for data

50. What is a bridge ID made up of?
Port
Bridge priority and MAC
By configuring every switch port to have an expected and controlled behavior
3 seconds. Holdtime =3 hellos + 1