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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 is the size of ISL encapsulation?
Collision domain
Configuration and TCN
Best effort delivery - integrated services model - and differentiated services model
26-byte header - 4-byte trailer with CRC

2. How should backbonefast be configured?
On all switches in network to enable RLQ request and reply
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
No

3. What's the easiest way to configure GLBP timers?
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.
802.1w
PAgP (Cisco proprietary) and LACP (standards-based)
Configure the timer on the AVG and let it propagate

4. What does MSTP consist of?
Regions and instances
Controls where candidate root bridges can be connected and found on a network
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
If a proposal is received - the recipient isolates - all nonedge ports blocked until proposal sent causing neighbors to synch - which propagates out in waves

5. What is a null adjacency?
Used to switch packets destined for the null interface
2
Cisco ILP and 802.3af
Control functions

6. How do VRRP routers handle preemption?
Both layer 2 switching and IVR
On by default
Globally
Auto mode

7. How is an RSTP edge port configured
Both layer 2 switching and IVR
A client can roam to any WLC as long as it stays in a mobility group
With portfast
Arp for local subnet - if on different subnet - will arp for dgw

8. What is common spanning tree (CST)?
Because each frame is checked
Controls where candidate root bridges can be connected and found on a network
Single instance of STP for all VLANs. BDPUs are sent over trunks using the native VLAN with untagged frames. Dot1q based
A packet can't be switched in hardware with the FIB and must go to the L3 engine

9. How is 802.1x configured for port security?
Port with best root path cost on segment
By brining up a tunnel between them to carry 802.11 related messages and client data.
RADIUS
By configuring every switch port to have an expected and controlled behavior

10. What is RPR?
A client can roam to any WLC as long as it stays in a mobility group
By encapsulating each frame in a header and trailer
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions

11. How often are CAM table entries aged?
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
Switch(config-if)# vrrp xx where xx= group number
300 sec
The distribution layer should have only L3 links

12. How does IPT behave when the voice VLAN is in vlan-id mode?
Data goes over native vlan - voice goes over specified VLAN - voice QOS is 802.1p
The number of times the CEF table has bee flushed and regenerated as a whole
Globally
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region

13. What is RTP?
Real-time Transport Protocol
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
A group of wireless devices that share a common SSID
Manages addition - deletion and renaming VLANs across the network

14. What is a VRRP group?
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
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.
Embeds the tag within the frame
The same as a standby group in HSRP

15. When a host is connected to a switchport - why aren't frame errors propagated?
By configuring every switch port to have an expected and controlled behavior
No
Because each frame is checked
Round robin - weighted - or host-dependent

16. How does the standby handle ARP issues after it becomes active?
L2
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
Checks the source MAC in the header against the sender MAC in the ARP reply
By sending a gratuitous ARP

17. What feedback mechanism does wireless use?
5 classes with 3 drop precedences
Sends a voltage across the receive pairs to detect a 25k ohm resistance
0-255
When a wireless station transmits a frame - the receiving one must send an ack

18. How do you renable an err-disable port by default?
Manually
Via an 802.1Q trunk or a single VLAN access port
PAgP (Cisco proprietary) and LACP (standards-based)
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains

19. 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
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
All nondesignated ports - but ok for all ports
The total delay from start to finish

20. How long are TCAM masks?
The frame tag contains a 3 but portion tagged from 0 (low) to 7 (high)
Lowest cumulative cost to root
134 bits
Trunk

21. can root guard and udld be used together?
Disabled - init - listen - speak - standby - active
Based on priority (0-255). Default is 100. Highest IP is tie breaker
2 seconds
Yes

22. By default - what layer do catalyst switchports operate on?
L2
Forces the router to wait for a period of time before attempting overthrow
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
Configure and enable DHCP snooping

23. EAP encryption
Usually QoS from VOIP but not PC dataa
Dynamic WEP keys that change periodically
It is enabled by default on all CEF capable switches
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p

24. what I s distributed CEF (dCEF)?
Access
Incoming frames dropped - but MACs learned
It can't
CEF is distributed completely among multiple L3 forwarding engines.

25. What is the STP forward delay timer?
A client can roam to any WLC as long as it stays in a mobility group
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
L2
The time that a port spends in both listening and learning states . Default 15 seconds

26. What is an IBSS?
A client can roam to any WLC as long as it stays in a mobility group
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated
Distribution layer
The wireless clients communicate directly with no other means of connectivity such as a WAP

27. How is Root Guard used?
Each frame transmits its expected duration time
On ports where you never expect to find a root bridge for a VLAN
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
Frames are forwarded

28. What is the STP blocking state?
Both ends should be on because on modes doesn't send PAgP or LACP packets
Based on priority (0-255). Default is 100. Highest IP is tie breaker
0-255
Can hear only BDPUs

29. What is a root link query (RLQ)?
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
Both layer 2 switching and IVR
When a port moves into forwarding or from fowarding or learning to blocking.

30. How is DHCP snooping enabled (scope)?
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
Globally
Option 43
By name - config revision - and instance to vlan mapping table

31. How are errdisable triggers tuned?
MAC of the end device
Packets are discarded due to an ACL or policy action
FE - GE - and aggregated FE/GE Etherchannels
Globally

32. Does a WLC and a LAP need to be on the same subnet?
All user ports that have portfast enabled
134 bits
No
Port with redundant - but less deisrable connection to a segment. Possibly root candidate

33. What 2 tunnelling mechanisms do the LAP and WLC use to communicate?
Both ends should be on because on modes doesn't send PAgP or LACP packets
Show standby
Another router must have a higher HSRP priority and have preemt set up
LWAPP (Cisco proprietary) and CAP-WAP (standards based)

34. How is the IPT 802.1 trunk negotiated?
If any BDUP is received on a port - it puts the port into the errdisable state
Automatically using DTP and CDP
The ASIC
Between interfaces that are assigned to L2 VLANs or L2 trunks

35. What is step 1 of enabling IP source guard?
Admin down
Yes
Only for trusted Cisco gear - especially phones
Configure and enable DHCP snooping

36. If there are 2 ports with same root cost - how is the tie broken for designated port?
Immediate (class 2)
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
2 seconds (def)
Connects to a router - firewall - or gateway. Can communicate with anything else connected to the primary or any secondary. Ignores pvlan config

37. What is the cost of a 100Mbps link?
Only when a nonedge port transitions to forwarding
On root - because the root bridge propagates timers with config BDPU
19
On ports where you never expect to find a root bridge for a VLAN

38. How do IP phones communicate with each other?
By configuring every switch port to have an expected and controlled behavior
L2
Port that connects to another switch and becomes a designated port
Once the CCM gives them the parameters - they use RTP

39. What is the bridge priority range?
Limits the number if dhcp requests on a port
When a wireless station transmits a frame - the receiving one must send an ack
0-65535 (def 32768) lower=better
Root

40. What can the Etherchannel hash use?
Frames that barely exceed 1518B or 1622B due to headers
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers

41. What does the reload keyword do in HSRP?
Both ends should be on because on modes doesn't send PAgP or LACP packets
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
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow

42. What are LOU register pairs?
7 switches from root bridge
With portfast
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
Used when ACLs specify port ranges...used by TCAM

43. What does a LAP do if it loses communication with it's WLC?
Reboots and searches for a new WLC
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
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology
Only the standby monitors the hello messages from the active router

44. How are BDPUs spread?
The link status stays up - but something between them has failed or is filtering traffic
The port is forced to always authorize any connected client with no authentication necessary (default)
VTP server for domain null with no password or secure mode
Multicast to 01-80-c2-00-00-00

45. How often are BDPUs sent?
2 seconds (def)
The same as a standby group in HSRP
Turn on port security
On the left as you face the connector

46. What are the 3 redundant supervisor modes?
The master router can share the VIP
RPR - RPR+ - and SSO
Connects with SONET or SDH
Root

47. How does an LAP bind with a WLC?
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
By name - config revision - and instance to vlan mapping table
By brining up a tunnel between them to carry 802.11 related messages and client data.

48. What duplex setting does 802.11 use and why?
Checks the sender's ip in all arp requests and checks the sender's IP against target IP in all replies
Half because transmitting and receiving stations use the same frequency
The port is forced to always authorize any connected client with no authentication necessary (default)
Switches make an effort to move packets as quickly as possible

49. Where is the QoS trust boundary usually configured on an IP phone?
Usually QoS from VOIP but not PC dataa
16 - of which up to 8 are active. The others are in standby
When the size of a cell is intentionally reduced
2 seconds (def)

50. How does DSCP handle IP precedence?
Round robin - weighted - or host-dependent
5 classes with 3 drop precedences
BGP - EIGRP - OSPF - and IS-IS.
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