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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 does a DAI enabled switch gather trusted ARP info?
Bridge priority and MAC
900 MHz - 2.4Ghz - and 5-6GHz
From the DHCP snooping database or from static entries
Using a mobility exchange message

2. How does the standby handle ARP issues after it becomes active?
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
If any BDUP is received on a port - it puts the port into the errdisable state
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
By sending a gratuitous ARP

3. What is the RSTP default hello interval?
2 seconds
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
Once the CCM gives them the parameters - they use RTP
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets

4. What ILP mode are all ports in by default?
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz
1-65535 (def 32768) lower priority - higher probability
Auto mode
Because each frame is checked

5. How does PAgP form etherchannels?
Per VLAN
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified
The station can transmit immediately and wait for an ack
Either desirable or auto mode

6. What are the 3 unlicensed frequencies?
Disabled - blocking - listening - learning - forwarding
Frames are forwarded
900 MHz - 2.4Ghz - and 5-6GHz
Virtual Router Redundancy Protocol - pretty much the same as HSRP

7. How do you prevent switch spoofing?
By configuring every switch port to have an expected and controlled behavior
LWAPP (Cisco proprietary) and CAP-WAP (standards based)
Yes
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information

8. Whan is a 10GE WAN PHY?
802.1D
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
Connects with SONET or SDH
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

9. How do you find duplex mismatches?
19
One that can be detected on a switch interface (ie. Up/down)
Distributed coordinion function - the use of timers to prevent wireless collisions
Use sh interface on the interface and look for error counts > 10

10. What is the VRRP master router?
Show standby
No
The active router. All other routers are in backup state
Trusted ports

11. Can two switches in the auto(PAgP) or passive (LACP) mode create a channel? Why?
Sends a voltage across the receive pairs to detect a 25k ohm resistance
RADIUS
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
No because they only participate if asked

12. What is the STP Max Age timer?
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
An L2 switch can only forward frames best effort unless going across a trunk
When the AP uplinks to an Ethernet network.

13. What are the 2 power over ethernet methods?
Cisco ILP and 802.3af
By using a hash of a key string
Access or trunk
Almost eliminates listening and learning states for single hosts on an access link

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

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15. Can MSTP interoperate with 802.1q and/or PVST+?
Half because transmitting and receiving stations use the same frequency
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
Transmits keystrokes from phone and commands from CCM
Yes to both

16. How does DSCP handle IP precedence?
Enables switches at the end of the spanning tree branches to have a functioning root port while keeping 1 or more redundant potential ports in blocking mode. When the main fails - the other comes up.
5 classes with 3 drop precedences
The link status stays up - but something between them has failed or is filtering traffic
802.1D

17. How does packet forwarding work
1-ID link path costs - 2-ID roodt bridge - 3-select root port (1/switch) - 4-select designated port (1/segment) - 5-ID blocking port
Arp for local subnet - if on different subnet - will arp for dgw
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
Incoming frames dropped - but MACs learned

18. What does UDLD do?
All nondesignated ports - but ok for all ports
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
Use sh interface on the interface and look for error counts > 10
Protects STP when a physical malfunction only allows traffic in 1 direction - even though the link shows as up (cisco proprietary)

19. What is route caching?

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20. How can BDPU Guard be configured?
63 kbps
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
Globally or per-port
Only for the offending VLAN on the port

21. What is a null adjacency?
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
That they aren't using the same frequencies.
Used to switch packets destined for the null interface
Root

22. What categories can ports be in with dhcp snooping enabled?
Trusted or untrusted
A packet can't be switched in hardware with the FIB and must go to the L3 engine
16 bits (8b port priority - 8b port number)
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan

23. What is the SDM?
All nondesignated ports - but ok for all ports
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
Switching Database Manager - configures and prunes TCAM partitions
Configure the timer on the AVG and let it propagate

24. Where shoul dmultilayer switches be implemented?
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
Distribution layer
To the virtual port-channel interface
Use the spanning-tree root macro

25. What are the RSTP port roles?
No
Root - designated - alternate - and backup
Reboots and searches for a new WLC
Collision domain

26. Does VTP pass private VLAN configuration?
L2
BGP - EIGRP - OSPF - and IS-IS.
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
No

27. What is layer 3 roaming?
Best effort delivery - integrated services model - and differentiated services model
Packets are discarded due to an ACL or policy action
When a client roams between Aps in different subnets
By using a hash of a key string

28. What cabling do GBICs use?
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
Two distribution switches that aggregate one or more access switches
SC fiber or RJ-45
1/2 and 3/6

29. What is the size of a TCAM value?
Using a mobility exchange message
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
The TOS field in the header is used. 2 methods 3 bits or 6 bits
134 bits - consisting of source and destination addresses and protocol information from the packet or frame

30. How can you load-balance with HSRP?
Arp for local subnet - if on different subnet - will arp for dgw
By using an Ether-IP tunnel
CEF is distributed completely among multiple L3 forwarding engines.
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each

31. What is backbonefast?
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
2 seconds (def)
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
Used to switch packets destined for the null interface

32. How does a WLC hand off a client's association to another WLC?
CEF is distributed completely among multiple L3 forwarding engines.
Interim solution - uses same hardware as WEP - but uses TKIP encryption
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
Using a mobility exchange message

33. What is a QoS trust boundary?
All ports where root isn't expected
Each frame transmits its expected duration time
The number of times the CEF table has bee flushed and regenerated as a whole
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP

34. How does IPT behave when the voice VLAN is in untagged mode?
The station can transmit immediately and wait for an ack
Data and voice over native vlan - no QOS but still uses 802.1p trunk
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
Arp for local subnet - if on different subnet - will arp for dgw

35. What does a LAP do if it loses communication with it's WLC?
Src-dst-ip
Reboots and searches for a new WLC
Port with best root path cost on segment
Once the CCM gives them the parameters - they use RTP

36. What is topology-basec caching?
When a wireless station transmits a frame - the receiving one must send an ack
The number of times the entry has been updated since the table was generated
The topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding
A single broadcast domain

37. RSTP forwarding state
1/2 and 3/6
Per VLAN
Frames are forwarded
Access

38. FE connectors use...
MAC of the end device
2 strand MMF with MT-RJ or SC connectors
0000.0c07.acxx where xx is the group number as a 2-digit hex value
0000.5e00.01xx

39. What is dynamic auto?
Will trunk if asked
Distribution layer
Immediate (class 2)
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal

40. What is the PVLAN host mode?
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan
The ASIC
Root - designated - blocking - alternate - forwarding (host)
26-byte header - 4-byte trailer with CRC

41. What are the 2 UDLD modes?
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
The distribution layer should have only L3 links
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
Normal and aggressive

42. What must the other end be set to if PAgP desirable or LACP active mode is selected?
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
Either desirable or auto mode
One that can be detected on a switch interface (ie. Up/down)
Immediate (class 2)

43. 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
Round robin - weighted - or host-dependent
802.1x with EAP over LAN (EAPOL)
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.

44. If the WLC connects to an Etherchannel - how should the channel be configured and why?

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45. What can cause a wireless client to switch between Aps?
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
Incoming frames dropped - but MACs learned
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority

46. What happens during HSRP failover?
Trunk - dynamic auto - dynamic desireable (default)
Distribution layer
The standby becomes active and stays active by default. Preemption can be configured
They must be carried over a voice VLAN (VVID) or over a regular data VLAN (ie. The native VLAN or the PVID)

47. If there are 2 ports with same root cost - how is the tie broken for designated port?
VTP server for domain null with no password or secure mode
Bridge priority and MAC
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
It is enabled by default on all CEF capable switches

48. What is a microcell?
SC fiber or RJ-45
0000.0c07.acxx where xx is the group number as a 2-digit hex value
When the size of a cell is intentionally reduced
Weak key rotation

49. What is the range of PAgP channel group numbers?
Use the spanning-tree root macro
Real-time Transport Protocol
Each frame transmits its expected duration time
1 to 64

50. What happens when switches receive a configuration BDPU?
The total delay from start to finish
Both layer 2 switching and IVR
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.