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 errdisable dtp-flap?
Change in trunk encap
0000.5e00.01xx
Arp for local subnet - if on different subnet - will arp for dgw
Round robin - weighted - or host-dependent


2. Can two switches in the auto(PAgP) or passive (LACP) mode create a channel? Why?
When a client roams between Aps in different subnets
No because they only participate if asked
The campus network's backbone
If the switch or the powered device doesn't suport power class discovery


3. What are the 2 power over ethernet methods?
Auto mode
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
Cisco ILP and 802.3af
Switches make an effort to move packets as quickly as possible


4. What is differentiated services model QOS?
80% of the user traffic should stay in the VLAN
On root - because the root bridge propagates timers with config BDPU
Each network device handles packets individually with no advance reservations
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable


5. Where is loop guard enabled?
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
Interim solution - uses same hardware as WEP - but uses TKIP encryption
All nondesignated ports - but ok for all ports
Switch(config-if)# vrrp xx where xx= group number


6. What is integrated services model QOS?
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
802.1x with EAP over LAN (EAPOL)
0-65535 (def 32768) lower=better
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.


7. What is the format of the VRRP virtual MAC?
Variation in delay
Full duplex
0-255
0000.5e00.01xx


8. Can MSTP interoperate with 802.1q and/or PVST+?
Yes to both
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
Isl - dot1q - negotiate (default)
Root


9. How does ISL do trunking?
16 bits (8b port priority - 8b port number)
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
By encapsulating each frame in a header and trailer
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


10. How does DAI work?
10-15%
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
It's a router that maintains routes (static or dynamic) - and populates the FIB
All ARP packets that arrive on untrusted ports are inspected.


11. When DHCP snooping is turned on - by default - it considers all ports ______
Switch(config-if)# vrrp xx where xx= group number
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology
Untrusted
Trusted or untrusted


12. What is PVST plus (PVST+)?
To a VLAN and not to a VLAN interface (SVI)
1- trunking mode - 2-trunk encapsulation - 3-native VLAN - 4-allowed VLAN
When the AP uplinks to an Ethernet network.
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL


13. What is RPR+?

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14. How do VRRP routers handle preemption?
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated
No because they only participate if asked
It can't
On by default


15. How much overlap should a wireless repeater have?
It's a router that maintains routes (static or dynamic) - and populates the FIB
1 IP subnet
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified
Roughly 50%


16. what I s distributed CEF (dCEF)?
CEF is distributed completely among multiple L3 forwarding engines.
Differentiated services code point
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q


17. How are BDPUs spread?
12 kbps with headers and compression
Real-time Transport Protocol
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
Multicast to 01-80-c2-00-00-00


18. What does the switchport host macro do?
LACP port priority
Enables portfast - sets the port to access and disables PAgP
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
Only when a nonedge port transitions to forwarding


19. What is the GLBP redirect timer?
No
Determines when the AVG will stop using the old VMAC in ARP replies
Use sh interface on the interface and look for error counts > 10
A packet can't be switched in hardware with the FIB and must go to the L3 engine


20. How often are CAM table entries aged?
Automatically using DTP and CDP
On ports where you never expect to find a root bridge for a VLAN
300 sec
The topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding


21. How does a Cisco IP phone connect upstream?
To a VLAN and not to a VLAN interface (SVI)
Switch(config-if)# standby xx where x= group number
Via an 802.1Q trunk or a single VLAN access port
A VLAN that spans the entire fabric


22. What is an insignificant topology change?
Almost eliminates listening and learning states for single hosts on an access link
A host port goes up or down
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry
Real-time functions such as beacons and probes - encryption and interactions with the client at L2


23. What are the 3 trunk switchport modes?
Reboots and searches for a new WLC
Trunk - dynamic auto - dynamic desireable (default)
Forces the router to wait for a period of time before attempting overthrow
Only when a nonedge port transitions to forwarding


24. How should UDLD be configured?
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
Matching SSID - compatible data rate - authentication credentials
The configureable UDLD interval must be less than max age plus two intervals of forward delay


25. What is a vlan?
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
A single broadcast domain
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset
Plain text or md5


26. What are the RSTP port states?
Discarding - learning - forwarding
Best effort delivery - integrated services model - and differentiated services model
Can send and receive BDPUs
Enables portfast - sets the port to access and disables PAgP


27. What is the port number range?
0-255
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
0000.5e00.01xx
Switching Database Manager - configures and prunes TCAM partitions


28. How does IPT behave when the voice VLAN is in dot1p mode?
Half-duplex
Cisco ILP and 802.3af
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p
Routers are assigned to common GLBP group. All routers can be active and can load balance


29. What is dhcp snooping rate limiting?
19
Frames are forwarded
Limits the number if dhcp requests on a port
The time that a port spends in both listening and learning states . Default 15 seconds


30. How does backbonefast determine whether alternative paths exist?
Multicast to 01-80-c2-00-00-00
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
Only a single host connects . If one BDPU is received - it is no longer an edge port
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


31. what should you do if you expect a PAgP capable switch at the other end vs. a server or host?
Configure non-silent submode
Port is forced to never authorize any connected client
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS


32. What does the SP do?
Only for the offending VLAN on the port
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
Weak key rotation
They must be carried over a voice VLAN (VVID) or over a regular data VLAN (ie. The native VLAN or the PVID)


33. Where is root guard enabled?

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34. How does PAgP form etherchannels?
2 strand MMF with MT-RJ or SC connectors
It is enabled by default on all CEF capable switches
LACP port priority
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified


35. What does the standby HSRP router do?
Automatically negotiates a common trunk mode between switches
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset
Only the standby monitors the hello messages from the active router
A group of wireless devices that share a common SSID


36. How should the switch port to which an autonomous AP be configured?
Trunk
4
Almost eliminates listening and learning states for single hosts on an access link
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client


37. What is latency?
The time that a port spends in both listening and learning states . Default 15 seconds
By brining up a tunnel between them to carry 802.11 related messages and client data.
LACP port priority
The total delay from start to finish


38. How can you tell if a switch block is too large?
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
Routers at the distribution layer become the bottlenecks or broadcast or multicast traffic slows the switches in the switch block
Access


39. How many links can be used in an EtherChannel?
Disabled - blocking - listening - learning - forwarding
Must be same type - speed - VLAN(s) - native vlan - pass the same set of vlans -duplex - and spanning tree settings
2-8 FE - GE - or 10GE are bundled.
No


40. How do you disable DTP when you configure both ends of the ISL manually?
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
Differentiated services
Packets are discarded due to an ACL or policy action
Switchpotrt nonegotiate


41. What are the PAgP negotiation modes
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
The total delay from start to finish
The port is forced to always authorize any connected client with no authentication necessary (default)
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated


42. What is a wall wart?
7 switches from root bridge
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
The campus network's backbone
An ac adaptor that plugs into a wall outlet.


43. What does the skinny protocol do?
Transmits keystrokes from phone and commands from CCM
Local only
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
Port


44. What are dynamic VLANs based on?
Using digital certificates
MAC of the end device
It is enabled by default on all CEF capable switches
Can hear only BDPUs


45. How much BW does a voip connection use?
With portfast
LWAPP (Cisco proprietary) and CAP-WAP (standards based)
Priority (class 1)
12 kbps with headers and compression


46. How should backbonefast be configured?
All user ports that have portfast enabled
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
On all switches in network to enable RLQ request and reply
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover


47. What is the default 802.3af power class and its use?

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48. What is route caching?

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49. What happens when the topology changes?

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50. What does VTP do?
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
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
The MST instance (MSTI) runs alongside the IST and represents an STP instance
Manages addition - deletion and renaming VLANs across the network