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CCNP Switch Deck

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. What functions does a LAP perform?
802.1w
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
A point to point port type but the neighboring device runs traditional 802.1D STP

2. What are the 3 trunk encap modes?
To a VLAN and not to a VLAN interface (SVI)
Isl - dot1q - negotiate (default)
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
Stateful switchover - redundant sup is fully booted and init'd. Both start and run config are synched as is L2 information - and switchinterfaces.

3. What address does HSRP send hello packets to?
224.0.0.2 (all routers)
A VLAN that spans the entire fabric
1-65535 (def 32768) lower priority - higher probability
On ports where you never expect to find a root bridge for a VLAN

4. What 2 tunnelling mechanisms do the LAP and WLC use to communicate?
Differentiated services
Etherchannel ports have inconsistent config
LWAPP (Cisco proprietary) and CAP-WAP (standards based)
12 kbps with headers and compression

5. How does HSRP gateway addressing work
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
Used when ACLs specify port ranges...used by TCAM
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers

6. Which 4 things must be agreeable to trunk?
12 kbps with headers and compression
No because they only participate if asked
1- trunking mode - 2-trunk encapsulation - 3-native VLAN - 4-allowed VLAN
0-255

7. How do you prevent VLAN hopping?
When the size of a cell is intentionally reduced
Set the native VLAN of a trunk to a bogus or unused VLAN ID then prune the native VLAN off both ends of the trunk
By name - config revision - and instance to vlan mapping table
134 bits

8. How does RSTP identify a topology change?
Option 43
When the size of a cell is intentionally reduced
It is enabled by default on all CEF capable switches
Only when a nonedge port transitions to forwarding

9. How does loop guard block ports?
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
Only for the offending VLAN on the port
It is enabled by default on all CEF capable switches
Between any type of interface as long as the interface can have an L3 address assigned

10. How is an instance defined?
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz
Dynamic arp inspection
By name - config revision - and instance to vlan mapping table
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds

11. At what layer should the WLC be connected?
Etherchannel ports have inconsistent config
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
A group of wireless devices that share a common SSID
Distribution

12. How often are CAM table entries aged?
Weak key rotation
300 sec
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
Switch(config-if)# glbp xx where xx = group number

13. On what scope is DAI enabled?
Yes
5 classes with 3 drop precedences
The redundant SUP is booted and sup and route engine is init'd. No L2 or L3 functions are started. Allows switchports to retain state
Per VLAN

14. What is a service set?
A group of wireless devices that share a common SSID
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
By short-circuiting the max age timer
Distribution

15. By default - what submode does PAgP operate in with the desirable and auto modes?
Port
Connects with SONET or SDH
Silent
Collision domain

16. How is the HSRP MAC address configured?
0000.0c07.acxx where xx is the group number as a 2-digit hex value
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.
0007.b4xx.xxyy where xx.xx is six 0 bits followed by a 10-bit GLBP group numberr. Yyyy is the virtual forwarder number
Full duplex

17. How does DSCP handle IP precedence?
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
5 classes with 3 drop precedences
From the DHCP snooping database or from static entries
By using a trunk link

18. How does VRRP do tracking?

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19. Does VTP pass private VLAN configuration?
Both ends should be on because on modes doesn't send PAgP or LACP packets
The DCF interframe space- the random backoff time before a wireless set can transmit
Trusted or untrusted
No

20. What is unique about HSRP group numbers?
Hosts within a secondary can communicate with each other and with the primary - but not with another secondary vlan
Use sh interface on the interface and look for error counts > 10
Show standby
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another

21. What is the VRRP skew time?
Switched Virtual Interface - an L3 address can be assigned to a logical interface that represents an entire VLAN - which becomes the DGW for that VLAN
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
0-65535 (def 32768) lower=better
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

22. What is RTP?
TCAM
Switching Database Manager - configures and prunes TCAM partitions
Real-time Transport Protocol
Half-duplex

23. What are the characteristics of the distribution layer?
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
It can't
Distributed coordinion function - the use of timers to prevent wireless collisions
Dynamic arp inspection

24. What is a null adjacency?
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
Globally or per-port
Used to switch packets destined for the null interface
Globally

25. How does backbonefast determine whether alternative paths exist?
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
A host port goes up or down
FIB
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge

26. EAP encryption
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
Dynamic WEP keys that change periodically
Frames are forwarded

27. Automatically configure STP timers
Regions and instances
That they aren't using the same frequencies.
Use the spanning-tree root macro
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority

28. What is RPVST+?
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
On the left as you face the connector
Switch(config-if)# standby xx where x= group number

29. What can the Etherchannel hash use?
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
To a VLAN and not to a VLAN interface (SVI)
RPR - RPR+ - and SSO
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers

30. How does the standby handle ARP issues after it becomes active?
By sending a gratuitous ARP
Edge - root - and point to point
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
CEF is distributed completely among multiple L3 forwarding engines.

31. What is an isolated secondary VLAN?

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32. How do you configure IP source guard for hosts that don't use DHCP?
Disabled - blocking - listening - learning - forwarding
By creating a static IP binding
No
1/2 and 3/6

33. How does IPT behave when the voce VLAN is in the default none mode?
Checks the destination MAC in the header against the target MAC in the ARP reply
26-byte header - 4-byte trailer with CRC
Data and voice over native vlan no QOS and no 802.1p trunk
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets

34. How many tunnels exist between the LAP and WLC?
No
Routers are assigned to common GLBP group. All routers can be active and can load balance
2 - one for control messages and one for data
SC fiber or RJ-45

35. Where is loop guard enabled?
It's a router that maintains routes (static or dynamic) - and populates the FIB
When a wireless station transmits a frame - the receiving one must send an ack
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
All nondesignated ports - but ok for all ports

36. What are TCAM entries composed of?
Value - mask - and result (VMR) combinations
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
Interim solution - uses same hardware as WEP - but uses TKIP encryption

37. What are the 6 HSRP states?
Only a single host connects . If one BDPU is received - it is no longer an edge port
No because they only participate if asked
Reboots and searches for a new WLC
Disabled - init - listen - speak - standby - active

38. What data does DHCP snooping track?
Automatically negotiates a common trunk mode between switches
When the AP uplinks to an Ethernet network.
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Completed dhcp bindings - mac addresses - IP addresses - etc.

39. What is the default FE duplex?
The port is forced to always authorize any connected client with no authentication necessary (default)
Trunk
Transmits keystrokes from phone and commands from CCM
Full duplex

40. the static port to vlan membership is handled in _____
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
The ASIC
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy

41. When are RSTP bdpus sent?
Yes
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology
Each network device handles packets individually with no advance reservations
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.

42. How does dot1q do trunking?
Each network device handles packets individually with no advance reservations
Port with alternative path to root less desirable than root
Embeds the tag within the frame
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)

43. What functions does a WLC perform?
Variation in delay
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
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
Control functions

44. What is the distribution layer best practice?
Configuration and TCN
Matching SSID - compatible data rate - authentication credentials
1 per segment
The distribution layer should have only L3 links

45. How is 802.1x configured for port security?
Data goes over native vlan - voice goes over specified VLAN - voice QOS is 802.1p
RADIUS
The standby becomes active and stays active by default. Preemption can be configured
The total delay from start to finish

46. What is the size of a TCAM value?
No
No shut
Arp for local subnet - if on different subnet - will arp for dgw
134 bits - consisting of source and destination addresses and protocol information from the packet or frame

47. How does a WLC hand off a client's association to another WLC?
Using digital certificates
Used to switch packets destined for the null interface
Using a mobility exchange message
From the DHCP snooping database or from static entries

48. What does the standby HSRP router do?
Packets must be sent to the L3 engine for further processing
As a VLAN access map
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.
Only the standby monitors the hello messages from the active router

49. What does UDLD do?
Flash override (class 4)
Protects STP when a physical malfunction only allows traffic in 1 direction - even though the link shows as up (cisco proprietary)
Weak key rotation
Roughly 2000

50. What does a LAP do if it loses communication with it's WLC?
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz
134 bits
Reboots and searches for a new WLC
Port with best root path cost on segment