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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 HSRP election work?
Based on priority (0-255). Default is 100. Highest IP is tie breaker
300 sec
Cisco recommends only on the root bridge
By configuring every switch port to have an expected and controlled behavior

2. How does 802.3af do power discovery?
Sends a voltage across the receive pairs to detect a 25k ohm resistance
Turn on port security
It can't
The number of times the CEF table has bee flushed and regenerated as a whole

3. Where is bdpu guard enabled?
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
All user ports that have portfast enabled
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority

4. What is dynamic auto?
CEF is distributed completely among multiple L3 forwarding engines.
224.0.0.2 (all routers)
Will trunk if asked
It can't

5. What is the VRRP skew time?
No
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
Needs hardware upgrade over WEP - uses AES encryption
It can't

6. RSTP BPDU structure
By sending a gratuitous ARP
Control functions
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p

7. What are the port channel load balancing methods?
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
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
The TOS field in the header is used. 2 methods 3 bits or 6 bits
A packet can't be switched in hardware with the FIB and must go to the L3 engine

8. What categories can ports be in with dhcp snooping enabled?
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
Trusted or untrusted
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string

9. What are the 3 unlicensed frequencies?
5 (0-4 with 4 being the highest)
Turn on port security
900 MHz - 2.4Ghz - and 5-6GHz
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz

10. FE connectors use...
2 strand MMF with MT-RJ or SC connectors
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated
Cisco recommends only on the root bridge
If the switch or the powered device doesn't suport power class discovery

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

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12. How is 802.1x configured for port security?
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
Automatically negotiates a common trunk mode between switches
Admin down
RADIUS

13. How does a LAP and a WLC authenticate between each other?
Using digital certificates
Packets are discarded due to an ACL or policy action
900 MHz - 2.4Ghz - and 5-6GHz
BGP - EIGRP - OSPF - and IS-IS.

14. What is the STP Max Age timer?
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
Group (0-1023) priority (1-255 higher better def 100)
Trusted ports
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

15. How does DAI work?
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
An AP's coverage area
All ARP packets that arrive on untrusted ports are inspected.

16. How doed backbonefast work?
1 second. Backup routers can learn the interval from the master
By short-circuiting the max age timer
Discarding - learning - forwarding
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

17. What does BDPU filtering do?
The master router can share the VIP
Port with best root path cost on segment
Effectively stops STP on filtered ports
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.

18. What is the port number range?
0-255
Critical...used most often for IPT
All user ports that have portfast enabled
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec

19. Where should STP timers be configured and why?
On root - because the root bridge propagates timers with config BDPU
Checks the destination MAC in the header against the target MAC in the ARP reply
3 seconds. Holdtime =3 hellos + 1
Only for the offending VLAN on the port

20. What are dynamic VLANs based on?
It's a router that maintains routes (static or dynamic) - and populates the FIB
Differentiated services
MAC of the end device
1-enable AAA on switch - 2-define RADIUS servers - 3-define authentication method - 4-enable 802.1x on switch - 5-conf. 802.1x ports - 6-allow hosts

21. What are the RSTP port states?
Globally
Discarding - learning - forwarding
FE - GE - and aggregated FE/GE Etherchannels
The number of times the CEF table has bee flushed and regenerated as a whole

22. What is the default MTU?
1500B
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
Cisco recommends only on the root bridge
Etherchannel ports have inconsistent config

23. How are GLBP timers used?
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
The time that a port spends in both listening and learning states . Default 15 seconds
Bridge priority and MAC

24. How do Cisco IP phones communicate with the CCM?
With the skinny protocol
Distribution layer
0-255
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy

25. 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
Reboots and searches for a new WLC
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
Switch(config-if)# standby xx where x= group number

26. What is the traditional MLS view of switching?
Using a mobility exchange message
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
Route once - switch many

27. Each switch port is a _____ ______
Collision domain
Used when there are 1 or more VLANs mapped to a single STP instance
TCAM
Interim solution - uses same hardware as WEP - but uses TKIP encryption

28. How is the IPT 802.1 trunk negotiated?
Automatically using DTP and CDP
Globally
Only the standby monitors the hello messages from the active router
Using digital certificates

29. How does HSRP plain text authentication work?
The MST instance (MSTI) runs alongside the IST and represents an STP instance
A key string of up to 8 characters is sent. Default is cisco.
10-15%
Using digital certificates

30. What types of authentication does HSRP allow?
Plain text or md5
Edge - root - and point to point
12 kbps with headers and compression
Once the CCM gives them the parameters - they use RTP

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

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32. What happens if both 802.1D and RSTP BDPUs are received?
CEF is distributed completely among multiple L3 forwarding engines.
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
2 seconds
A private VLAN can be logically associated with a special secondary vlan

33. When DHCP snooping is turned on - by default - it considers all ports ______
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS
0000.5e00.01xx
L2
Untrusted

34. How does ISL handle COS?
Port is forced to never authorize any connected client
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
The frame tag contains a 3 but portion tagged from 0 (low) to 7 (high)
Immediate (class 2)

35. What are the 5 STP port roles?
Forces the router to wait for a period of time before attempting overthrow
Root - designated - blocking - alternate - forwarding (host)
Group (0-1023) priority (1-255 higher better def 100)
A group of wireless devices that share a common SSID

36. What does the src-mac option do when checking ARP replies
Checks the source MAC in the header against the sender MAC in the ARP reply
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
Globally
Sends a voltage across the receive pairs to detect a 25k ohm resistance

37. What is layer 2 roaming?
Incoming frames dropped - but MACs learned
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance
If the client maintains the same IP address as it roams between Aps. All must have same VLAN - SSID - and subnet
With portfast

38. What is UDLD aggressive mode?

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39. How are errdisable triggers tuned?
The distribution layer should have only L3 links
Globally
Value - mask - and result (VMR) combinations
2 seconds

40. What is the RSTP default hello interval?
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.
Discarding - learning - forwarding
2 seconds
Access or trunk

41. If one end of an Etherchannel (either type) is set to on and the channel doesn't form - what should you check?

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42. How does a WLC hand off a client's association to another WLC?
224.0.0.2 (all routers)
Using a mobility exchange message
On root - because the root bridge propagates timers with config BDPU
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow

43. How does HSRP do MD5 authentication?
By using a hash of a key string
Dynamic arp inspection
300 sec
Group (0-255) - priority (1-254 254 is highest - 100 default)

44. How does IPT behave when the voice VLAN is in vlan-id mode?
By using a trunk link
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS
Embeds the tag within the frame
Data goes over native vlan - voice goes over specified VLAN - voice QOS is 802.1p

45. How do you configure DAI for statically configured IP addresses?
An L2 switch can only forward frames best effort unless going across a trunk
By an ARP access list that defines the permitted bindings
Configure non-silent submode
Using digital certificates

46. How many tunnels exist between the LAP and WLC?
134 bits
2 - one for control messages and one for data
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
3 seconds. Holdtime =3 hellos + 1

47. How does an L2 switch do QOS?
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
An L2 switch can only forward frames best effort unless going across a trunk

48. What is an indirect topology change?
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
The link status stays up - but something between them has failed or is filtering traffic
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
All user ports that have portfast enabled

49. What must the other end be set to if PAgP desirable or LACP active mode is selected?
When a specific interface is tracked - HSRP reduces it's priority after a specified interval.
Either desirable or auto mode
Edge - root - and point to point
They must be carried over a voice VLAN (VVID) or over a regular data VLAN (ie. The native VLAN or the PVID)

50. How is DHCP snooping enabled (scope)?
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack
Globally
Flash (class 3)