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 2 tunnelling mechanisms do the LAP and WLC use to communicate?
Manually
LWAPP (Cisco proprietary) and CAP-WAP (standards based)
Used when ACLs specify port ranges...used by TCAM
The number of times the CEF table has bee flushed and regenerated as a whole


2. What is an isolated secondary VLAN?

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3. What is the bridge priority range?
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
0-65535 (def 32768) lower=better
Promiscuous and host
A private VLAN can be logically associated with a special secondary vlan


4. How does an L2 switch do QOS?
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
Another router must have a higher HSRP priority and have preemt set up
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.
An L2 switch can only forward frames best effort unless going across a trunk


5. What feedback mechanism does wireless use?
When a wireless station transmits a frame - the receiving one must send an ack
Another router must have a higher HSRP priority and have preemt set up
Gateway load balancing protocol - cisco proprietary
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)


6. What does uplinkfast do?
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.
Group (0-1023) priority (1-255 higher better def 100)
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
Receives the first packet of a traffic flow and routes it


7. How does the CEF L3 engine operate?

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8. What is backbonefast?
Dynamic WEP keys that change periodically
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
224.0.0.2 (all routers)
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure


9. How does IPT behave when the voice VLAN is in vlan-id mode?
1- trunking mode - 2-trunk encapsulation - 3-native VLAN - 4-allowed VLAN
1500B
Plain text or md5
Data goes over native vlan - voice goes over specified VLAN - voice QOS is 802.1p


10. When looking at the sh spanning tree output - What does P2P denote?
Trusted or untrusted
A point to point port type
Gateway load balancing protocol - cisco proprietary
Root - designated - blocking - alternate - forwarding (host)


11. What types of links can be trunked?
By configuring every switch port to have an expected and controlled behavior
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
FE - GE - and aggregated FE/GE Etherchannels
A single broadcast domain


12. What are the characteristics of the access layer?
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS


13. How does loop guard block ports?
Only for the offending VLAN on the port
Virtual Router Redundancy Protocol - pretty much the same as HSRP
MST attributes must be manually entereed on each switch in the region. They don' t propagate like VTP.
Distribution


14. What is errdisable dtp-flap?
Change in trunk encap
The distribution layer should have only L3 links
1 per segment
Only when a nonedge port transitions to forwarding


15. How does DAI work?
Dynamic WEP keys that change periodically
All ARP packets that arrive on untrusted ports are inspected.
Turn on port security
19


16. How does VRRP do tracking?

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17. How does DSCP handle IP precedence?
5 classes with 3 drop precedences
80% of the user traffic should stay in the VLAN
Real-time Transport Protocol
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack


18. How do IP phones communicate with each other?
A port can only forward or relay BDPUs - but can't receive them - disabled by default - enabled per-port - blocks port when superior BDPUs are received
Once the CCM gives them the parameters - they use RTP
An L2 switch can only forward frames best effort unless going across a trunk
Roughly 50%


19. How often are BDPUs sent?
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack
The station can transmit immediately and wait for an ack
2 seconds (def)
Auto mode


20. What is the STP Max Age timer?
5 (0-4 with 4 being the highest)
12 kbps with headers and compression
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds


21. What is the LACP priority range?
The total delay from start to finish
1-65535 (def 32768) lower priority - higher probability
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
Multicast to 01-80-c2-00-00-00


22. What is the size of a TCAM value?
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
Almost eliminates listening and learning states for single hosts on an access link


23. What is portfast?
They must be carried over a voice VLAN (VVID) or over a regular data VLAN (ie. The native VLAN or the PVID)
Port that connects to another switch and becomes a designated port
A TCN BDPU is sent out of the switch's root port. The switch will continue sending TCN's every hello interval until ack'd by upstream neighbor. The root bridge will send a Config BDPU to all switches
Almost eliminates listening and learning states for single hosts on an access link


24. What is the 80/20 rule?
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
80% of the user traffic should stay in the VLAN
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz
10-15%


25. What is a CEF punt?

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26. How is the IPT 802.1 trunk negotiated?
Automatically using DTP and CDP
Both ends should be on because on modes doesn't send PAgP or LACP packets
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
Up to 4 can be used in a group. Called active virtual forwarders (AVF)


27. 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
4
When a specific interface is tracked - HSRP reduces it's priority after a specified interval.
Access or trunk


28. RSTP edge port
RADIUS
Only a single host connects . If one BDPU is received - it is no longer an edge port
Src-dst-ip
TCAM


29. What is 802.1x force-unauthorized?
Port is forced to never authorize any connected client
SC fiber or RJ-45
By configuring every switch port to have an expected and controlled behavior
No


30. What is the default VTP state?
1/2 and 3/6
Routers are assigned to common GLBP group. All routers can be active and can load balance
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
VTP server for domain null with no password or secure mode


31. If there are 2 ports with same root cost - how is the tie broken for designated port?
By configuring every switch port to have an expected and controlled behavior
It's a router that maintains routes (static or dynamic) - and populates the FIB
0000.5e00.01xx
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID


32. where does L2 switching occur?
0-255
Half-duplex
Between interfaces that are assigned to L2 VLANs or L2 trunks
Data and voice over native vlan - no QOS but still uses 802.1p trunk


33. What is the IEEE standard for STP?
Using a single WAP to centralize access and control over a group of wireless devices.
A client can roam to any WLC as long as it stays in a mobility group
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.
802.1D


34. Which ports should you consider trusted for DAI?
By brining up a tunnel between them to carry 802.11 related messages and client data.
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
Those that connect to other switches
Configuration and TCN


35. What is DSCP codepoint AF21(18)?
Turn on port security
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
Immediate (class 2)
Prevents the dhcp binding DB from being checked.


36. What does the SP do?
Listens to the first packet going to router and away from the router. If it can switch in both directions - it learns a shortcut path so subsequent packets can be switched without the RP
16 - of which up to 8 are active. The others are in standby
Port
No shut


37. What is the STP forward delay timer?
Stateful switchover - redundant sup is fully booted and init'd. Both start and run config are synched as is L2 information - and switchinterfaces.
Either desirable or auto mode
The time that a port spends in both listening and learning states . Default 15 seconds
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS


38. What does port-security protect do?
Port stays up - packets from violating MACs dropped - no logging
Between interfaces that are assigned to L2 VLANs or L2 trunks
Root - designated - alternate - and backup
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information


39. What are the 6 HSRP states?
No
Isolated and community
Isl - dot1q - negotiate (default)
Disabled - init - listen - speak - standby - active


40. What is RPR+?

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41. How many links can be used in an EtherChannel?
Frames that barely exceed 1518B or 1622B due to headers
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
By configuring every switch port to have an expected and controlled behavior
2-8 FE - GE - or 10GE are bundled.


42. What types of link can an etherchannel be?
Access or trunk
No
16 bits (8b port priority - 8b port number)
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance


43. What routing protocols support NSF?
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology
BGP - EIGRP - OSPF - and IS-IS.
Used when there are 1 or more VLANs mapped to a single STP instance


44. What is the GLBP redirect timer?
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
Untrusted
Determines when the AVG will stop using the old VMAC in ARP replies
Port with redundant - but less deisrable connection to a segment. Possibly root candidate


45. What cabling do GBICs use?
SC fiber or RJ-45
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
The standby becomes active and stays active by default. Preemption can be configured


46. What is a service set?
Switches make an effort to move packets as quickly as possible
One router is the active virtual gateway - has highest priority or IP in group - answers all ARP requests and gives MAC based on load balancing
Forces the router to wait for a period of time before attempting overthrow
A group of wireless devices that share a common SSID


47. What does port-security restrict do?
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
Real-time Transport Protocol
The campus network's backbone
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


48. What must be supported for port-based security to occur?
802.11
1 second. Backup routers can learn the interval from the master
Variation in delay
802.1x with EAP over LAN (EAPOL)


49. How do you configure IP source guard for hosts that don't use DHCP?
1 IP subnet
Only for trusted Cisco gear - especially phones
Normal and aggressive
By creating a static IP binding


50. What is a proxy arp?

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