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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 often are HSRP hellos sent?
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
Yes
Can hear only BDPUs
3 seconds. Holdtime =3 hellos + 1

2. Automatically configure STP timers
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified
Use the spanning-tree root macro
Globally
Multicasts to 224.0.0.18 (VRRP)

3. What is the STP listening state?
Hashing algorithm
The port asks the other end to trunk
Can send and receive BDPUs
Differentiated services code point

4. What is layer 2 roaming?
To a VLAN and not to a VLAN interface (SVI)
If the client maintains the same IP address as it roams between Aps. All must have same VLAN - SSID - and subnet
16 - of which up to 8 are active. The others are in standby
A client can roam to any WLC as long as it stays in a mobility group

5. How does 802.3af do power discovery?
Cisco ILP and 802.3af
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
Virtual Router Redundancy Protocol - pretty much the same as HSRP
Sends a voltage across the receive pairs to detect a 25k ohm resistance

6. How do you find duplex mismatches?
Control functions
Use sh interface on the interface and look for error counts > 10
The switch checks the MAC and IP reported in the reply against trusted values. If they don't match - it is dropped and logged
Because each frame is checked

7. What is BDPU Guard?
If any BDUP is received on a port - it puts the port into the errdisable state
Regions and instances
VTP server for domain null with no password or secure mode
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset

8. Does GLBP allow preemption?
Receives the first packet of a traffic flow and routes it
No shut
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
Yes

9. How does a DHCP server send WLC addresses?
Because each frame is checked
Option 43
The port asks the other end to trunk
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow

10. What does port-security protect do?
Incoming frames are dropped (combination of disabled - blocking - and listening)
Because each frame is checked
Port stays up - packets from violating MACs dropped - no logging
4

11. 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
16 bits (8b port priority - 8b port number)
Switch(config-if)# glbp xx where xx = group number
By encapsulating each frame in a header and trailer

12. What 2 tunnelling mechanisms do the LAP and WLC use to communicate?
Used to switch packets destined for the null interface
Either desirable or auto mode
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology
LWAPP (Cisco proprietary) and CAP-WAP (standards based)

13. If a wireless station needs to transmit and another device is transmitting - what happens?
TCAM
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
Data and voice over native vlan no QOS and no 802.1p trunk

14. What is a wall wart?
An ac adaptor that plugs into a wall outlet.
19
Distribution layer
5 classes with 3 drop precedences

15. What is the duration time in a wireless frame?
134 bits
Port is forced to never authorize any connected client
When a wireless station transmits a frame - the receiving one must send an ack
Each frame transmits its expected duration time

16. In a converged fabric - which switch(es) send config BDPUs?
4
Determines when the AVG will stop using the old VMAC in ARP replies
Root
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable

17. What does MSTP consist of?
Regions and instances
Show standby
1-1005 (1 and 1002-1005 are reserved)
Yes

18. How are VACLs configured?
By using an Ether-IP tunnel
By creating a static IP binding
As a VLAN access map
The active router. All other routers are in backup state

19. What is DSCP codepoint AF21(18)?
Immediate (class 2)
2 strand MMF with MT-RJ or SC connectors
Trunk
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds

20. When looking at the sh spanning tree output - What does P2P denote?
Isl - dot1q - negotiate (default)
A point to point port type
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
A point to point port type but the neighboring device runs traditional 802.1D STP

21. What scope is 802.1x enabled?
802.1D
Globally
Roughly 50%
Used when there are 1 or more VLANs mapped to a single STP instance

22. What is backbonefast?
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
The wireless clients communicate directly with no other means of connectivity such as a WAP

23. How does HSRP do MD5 authentication?
Either desirable or auto mode
By using a hash of a key string
Root
Automatically by duplex mode in use. Full duplex are point ot point. Half duplex ports use traditional 802.1D convergence is used.

24. What is arp throttling?
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS
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
Globally
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)

25. RSTP BPDU structure
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
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 point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
Port is forced to never authorize any connected client

26. What is the port number range?
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
0-255
Between any type of interface as long as the interface can have an L3 address assigned
Incoming frames dropped - but MACs learned

27. What is a drop adjacency?

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28. What does the reload keyword do in HSRP?
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
By brining up a tunnel between them to carry 802.11 related messages and client data.
Matching SSID - compatible data rate - authentication credentials

29. What does Loop Guard do?
A client can roam to any WLC as long as it stays in a mobility group
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
Flash (class 3)
Root - designated - alternate - and backup

30. What is DSCP codepoint EF(46)?
By default weight is 100. Can be made dynamic per interface
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
Critical...used most often for IPT
Turn on port security

31. Can ARP replies be checked
Automatically negotiates a common trunk mode between switches
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
1 second. Backup routers can learn the interval from the master
Yes

32. How is RSTP synchronization accomplished?
1 per segment
900 MHz - 2.4Ghz - and 5-6GHz
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
Frames that barely exceed 1518B or 1622B due to headers

33. what I s distributed CEF (dCEF)?
802.1D
CEF is distributed completely among multiple L3 forwarding engines.
2 - one for control messages and one for data
Data and voice over native vlan no QOS and no 802.1p trunk

34. What is the cost of a 1Gbps link?
Incoming frames are dropped (combination of disabled - blocking - and listening)
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
4
Arp for local subnet - if on different subnet - will arp for dgw

35. What is a CEF punt?

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36. How do you show HSRP status
Show standby
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
Between interfaces that are assigned to L2 VLANs or L2 trunks
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS

37. How does a WLC hand off a client's association to another WLC?
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
Using a mobility exchange message
All nondesignated ports - but ok for all ports
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS

38. How are errdisable triggers tuned?
Globally
L2
1-1005 (1 and 1002-1005 are reserved)
The TOS field in the header is used. 2 methods 3 bits or 6 bits

39. How do you disable DTP when you configure both ends of the ISL manually?
When the AP uplinks to an Ethernet network.
The port asks the other end to trunk
Switchpotrt nonegotiate
By encapsulating each frame in a header and trailer

40. What does the standby HSRP router do?
Multicast to 01-80-c2-00-00-00
1500B
Only the standby monitors the hello messages from the active router
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz

41. What is the format of the VRRP virtual MAC?
Only a single host connects . If one BDPU is received - it is no longer an edge port
By creating a static IP binding
19
0000.5e00.01xx

42. What is the STP Max Age timer?
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
Edge - root - and point to point
Immediate (class 2)
Switchpotrt nonegotiate

43. How often are CAM table entries aged?
Differentiated services
Value - mask - and result (VMR) combinations
300 sec
The port asks the other end to trunk

44. What must you be sure of if AP cells overlap?

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45. When should CDP be enabled?
Embeds the tag within the frame
Via an 802.1Q trunk or a single VLAN access port
Frames are forwarded
Only for trusted Cisco gear - especially phones

46. What routing protocols support NSF?
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
Full duplex
BGP - EIGRP - OSPF - and IS-IS.
Local only

47. Define HSRP
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
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
Switching Database Manager - configures and prunes TCAM partitions
4

48. What is DSCP codepoint AF31(26)?
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another
Flash (class 3)
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz
Connects with SONET or SDH

49. What must be supported for port-based security to occur?
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
802.1x with EAP over LAN (EAPOL)
On the left as you face the connector
Yes to both

50. How are GLBP timers used?
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec
Best effort delivery - integrated services model - and differentiated services model
1 second. Backup routers can learn the interval from the master
Trunk