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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. How do you configure LACP standby links?
Only for the offending VLAN on the port
Discarding - learning - forwarding
By name - config revision - and instance to vlan mapping table
LACP port priority

2. What is an untrusted port under dhcp snooping?
Every switch and router in a network must be configured with appropriate QoS features and policies
Once the CCM gives them the parameters - they use RTP
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
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.

3. When looking at the sh spanning tree output - What does P2P peer(STP) denote?
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz
The standby becomes active and stays active by default. Preemption can be configured
The TOS field in the header is used. 2 methods 3 bits or 6 bits
A point to point port type but the neighboring device runs traditional 802.1D STP

4. What is 802.1x force-unauthorized?
Checks the destination MAC in the header against the target MAC in the ARP reply
Hosts within a secondary can communicate with each other and with the primary - but not with another secondary vlan
Port is forced to never authorize any connected client
Untrusted

5. What is errdisable dtp-flap?
The MST instance (MSTI) runs alongside the IST and represents an STP instance
Based on priority (0-255). Default is 100. Highest IP is tie breaker
Turn on port security
Change in trunk encap

6. What is the VRRP skew time?
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
1500B
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
Manages addition - deletion and renaming VLANs across the network

7. How does a DAI enabled switch gather trusted ARP info?
An L2 switch can only forward frames best effort unless going across a trunk
Distribution layer
From the DHCP snooping database or from static entries
Route once - switch many

8. What are the PAgP negotiation modes
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
Disabled - blocking - listening - learning - forwarding
Sends a voltage across the receive pairs to detect a 25k ohm resistance
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)

9. What are the 3 trunk encap modes?
Isl - dot1q - negotiate (default)
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
Src-dst-ip
Multicasts to 224.0.0.18 (VRRP)

10. What is unique about HSRP group numbers?
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another
Receives the first packet of a traffic flow and routes it
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

11. What is a null adjacency?
Used to switch packets destined for the null interface
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable

12. Where is bdpu guard enabled?
All user ports that have portfast enabled
Best effort delivery - integrated services model - and differentiated services model
Checks the source MAC in the header against the sender MAC in the ARP reply
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset

13. What does MSTP consist of?
12 kbps with headers and compression
Checks the source MAC in the header against the sender MAC in the ARP reply
Regions and instances
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table

14. What is the adjacency table?
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
Globally
802.11
That they aren't using the same frequencies.

15. How many users should be within a switch block?
When the AP uplinks to an Ethernet network.
Roughly 2000
Distribution layer
2 strand MMF with MT-RJ or SC connectors

16. What is the FM?
The same as a standby group in HSRP
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
By using a hash of a key string

17. Where shoul dmultilayer switches be implemented?
Yes to both
1-65535 (def 32768) lower priority - higher probability
Incoming frames are dropped (combination of disabled - blocking - and listening)
Distribution layer

18. How does loop guard block ports?
By an ARP access list that defines the permitted bindings
Forces the router to wait for a period of time before attempting overthrow
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
Only for the offending VLAN on the port

19. How does the CEF L3 engine operate?

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20. What is dynamic auto?
0000.5e00.01xx
Will trunk if asked
The station can transmit immediately and wait for an ack
Access or trunk

21. RSTP learning state
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack
Silent
The MST instance (MSTI) runs alongside the IST and represents an STP instance
Incoming frames dropped - but MACs learned

22. 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
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
Switchpotrt nonegotiate
On the left as you face the connector

23. unknown unicast flooding
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.
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
CEF is distributed completely among multiple L3 forwarding engines.
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry

24. How much overlap should a wireless repeater have?
Both layer 2 switching and IVR
Roughly 50%
The DCF interframe space- the random backoff time before a wireless set can transmit
CEF is distributed completely among multiple L3 forwarding engines.

25. What are the three basic types of QOS?
Best effort delivery - integrated services model - and differentiated services model
0-255
Using a single WAP to centralize access and control over a group of wireless devices.
The campus network's backbone

26. How does 802.3af do power discovery?
CEF is distributed completely among multiple L3 forwarding engines.
Sends a voltage across the receive pairs to detect a 25k ohm resistance
Frames are forwarded
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

27. What is a wireless mobility group?
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
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
TCAM
A client can roam to any WLC as long as it stays in a mobility group

28. What ILP mode are all ports in by default?
Auto mode
0-65535 (def 32768) lower=better
Turn on port security
Distribution

29. What routing protocols support NSF?
RPR - RPR+ - and SSO
All ports where root isn't expected
BGP - EIGRP - OSPF - and IS-IS.
Per VLAN

30. What are the steps of RSTP convergence?
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
Use sh interface on the interface and look for error counts > 10
Collision domain
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p

31. What is the STP hello timer?
Time between BDPUs sent by root bridge. Default of 2 seconds
5 (0-4 with 4 being the highest)
The time that a port spends in both listening and learning states . Default 15 seconds
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge

32. What does the epoch number indicate when looking at cef entries?
Only for the offending VLAN on the port
The number of times the CEF table has bee flushed and regenerated as a whole
Group (0-255) - priority (1-254 254 is highest - 100 default)
0-255

33. the static port to vlan membership is handled in _____
Configuration and TCN
The ASIC
Every switch and router in a network must be configured with appropriate QoS features and policies
The number of times the entry has been updated since the table was generated

34. can root guard and udld be used together?
A point to point port type
No shut
Yes
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

35. WEP encryption
Using a mobility exchange message
A point to point port type but the neighboring device runs traditional 802.1D STP
Weak key rotation
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

36. What is the SDM?
Cisco ILP and 802.3af
With the skinny protocol
By using a hash of a key string
Switching Database Manager - configures and prunes TCAM partitions

37. Which 4 things must be agreeable to trunk?
1- trunking mode - 2-trunk encapsulation - 3-native VLAN - 4-allowed VLAN
Roughly 50%
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
VTP server for domain null with no password or secure mode

38. What can the Etherchannel hash use?
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
Flash override (class 4)

39. What is a punt adjacency?
The campus network's backbone
Packets must be sent to the L3 engine for further processing
12 kbps with headers and compression
When the size of a cell is intentionally reduced

40. What is a topology change?
By sending a gratuitous ARP
It is enabled by default on all CEF capable switches
When a port moves into forwarding or from fowarding or learning to blocking.
Two distribution switches that aggregate one or more access switches

41. Automatically configure STP timers
Port stays up - packets from violating MACs dropped - no logging
Routers at the distribution layer become the bottlenecks or broadcast or multicast traffic slows the switches in the switch block
Use the spanning-tree root macro
0-255

42. WPA encryption
Based on priority (0-255). Default is 100. Highest IP is tie breaker
Protects STP when a physical malfunction only allows traffic in 1 direction - even though the link shows as up (cisco proprietary)
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
Interim solution - uses same hardware as WEP - but uses TKIP encryption

43. How do you configure a DHCP gateway?
Controls where candidate root bridges can be connected and found on a network
Admin down
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server

44. How many 802.3af power classes are there?
5 (0-4 with 4 being the highest)
Disabled - blocking - listening - learning - forwarding
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.
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

45. How does UDLD work?
Each frame transmits its expected duration time
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Port
When each AP stands alone within the larger network.

46. How is RSTP synchronization accomplished?
Access
1-1005 (1 and 1002-1005 are reserved)
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
1 IP subnet

47. How does L3 QOS classification happen?
The TOS field in the header is used. 2 methods 3 bits or 6 bits
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
Switches make an effort to move packets as quickly as possible
Port

48. What does MSTP do?
Used when there are 1 or more VLANs mapped to a single STP instance
L2
From the DHCP snooping database or from static entries
1 to 64

49. What is 802.1x force-authorized?
Configure the timer on the AVG and let it propagate
134 bits
The port is forced to always authorize any connected client with no authentication necessary (default)
Per VLAN

50. How does DSCP handle IP precedence?
5 classes with 3 drop precedences
Hashing algorithm
0000.5e00.01xx
Configure the timer on the AVG and let it propagate