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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 Per VLAN STP (PVST)?
The ASIC
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.

2. Which ports should you consider trusted for DAI?
Those that connect to other switches
By an ARP access list that defines the permitted bindings
Configure and enable DHCP snooping
Round robin - weighted - or host-dependent

3. How many virtual MACs can GLBP have?
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
Only a single host connects . If one BDPU is received - it is no longer an edge port
Trunk

4. WPA2 encryption
Needs hardware upgrade over WEP - uses AES encryption
Data and voice over native vlan no QOS and no 802.1p trunk
Frames are forwarded
Can send and receive BDPUs

5. How does a DAI enabled switch gather trusted ARP info?
Per VLAN
From the DHCP snooping database or from static entries
No shut
Port

6. What is the STP listening state?
Half-duplex
Can send and receive BDPUs
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
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

7. How does ISL do trunking?
Distribution layer
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
By encapsulating each frame in a header and trailer

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

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9. What is RPVST+?
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive
It is enabled by default on all CEF capable switches
802.11

10. What criteria are used to size a switch block?
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains
Priority (class 1)
The link status stays up - but something between them has failed or is filtering traffic
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal

11. What is NSF?
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
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
Using a mobility exchange message

12. How should backbonefast be configured?
On all switches in network to enable RLQ request and reply
CEF is distributed completely among multiple L3 forwarding engines.
Both ends should be on because on modes doesn't send PAgP or LACP packets
With portfast

13. How does Root Guard work?

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14. What is jitter?
Variation in delay
Use the spanning-tree root macro
Either desirable or auto mode
Distribution layer

15. What does the skinny protocol do?
Transmits keystrokes from phone and commands from CCM
Because each frame is checked
Auto mode
Via an 802.1Q trunk or a single VLAN access port

16. When a host is connected to a switchport - why aren't frame errors propagated?
Another router must have a higher HSRP priority and have preemt set up
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
Because each frame is checked
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting

17. For QoS - switch uplinks should always be considered as ____ _____?
2 seconds (def)
A group of wireless devices that share a common SSID
Trusted ports
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP

18. How much overlap should a wireless repeater have?
Configure the timer on the AVG and let it propagate
Roughly 50%
An ac adaptor that plugs into a wall outlet.
By short-circuiting the max age timer

19. What is the portr ID?
16 bits (8b port priority - 8b port number)
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Sends a voltage across the receive pairs to detect a 25k ohm resistance
1 second. Backup routers can learn the interval from the master

20. Which fiber is the receive?
On the left as you face the connector
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
The topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding
An L2 switch can only forward frames best effort unless going across a trunk

21. What is a service set?
12 kbps with headers and compression
Trusted ports
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
A group of wireless devices that share a common SSID

22. What does Loop Guard do?
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
The distribution layer should have only L3 links
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
RPR - RPR+ - and SSO

23. Where is UDLD enabled?
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
Because each frame is checked
All fiber-optic links between switches (must be enabled on both ends)
Another router must have a higher HSRP priority and have preemt set up

24. What does the SP do?
A private VLAN can be logically associated with a special secondary vlan
The master router can share the VIP
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
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS

25. What does the static keyword do when applying an arp ACL?
Bridge priority and MAC
Prevents the dhcp binding DB from being checked.
Both ends should be on because on modes doesn't send PAgP or LACP packets
Each network device handles packets individually with no advance reservations

26. What is errdisable pagp-flap?
Etherchannel ports have inconsistent config
Only for the offending VLAN on the port
By using a trunk link
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added

27. What is a microcell?
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
When the size of a cell is intentionally reduced
No because they only participate if asked
LACP port priority

28. What routing protocols support NSF?
BGP - EIGRP - OSPF - and IS-IS.
Frames are forwarded
Port stays up - packets from violating MACs dropped - no logging
Arp for local subnet - if on different subnet - will arp for dgw

29. What is the PVLAN promiscuous mode?
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
802.11
The port is forced to always authorize any connected client with no authentication necessary (default)
Connects to a router - firewall - or gateway. Can communicate with anything else connected to the primary or any secondary. Ignores pvlan config

30. How often are CAM table entries aged?
Routers at the distribution layer become the bottlenecks or broadcast or multicast traffic slows the switches in the switch block
A host port goes up or down
300 sec
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table

31. How are GLBP timers used?
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
By short-circuiting the max age timer
When a specific interface is tracked - HSRP reduces it's priority after a specified interval.
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec

32. What does uplinkfast do?
The number of times the entry has been updated since the table was generated
Only a single host connects . If one BDPU is received - it is no longer an edge port
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.
10-15%

33. What are the 5 steps to manualy configure STP?
Cisco ILP and 802.3af
Root - designated - alternate - and backup
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
Automatically using DTP and CDP

34. What is DSCP?
Manages addition - deletion and renaming VLANs across the network
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
Differentiated services code point
Controls where candidate root bridges can be connected and found on a network

35. When looking at the sh spanning tree output - What does P2P peer(STP) denote?
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
No shut
Arp for local subnet - if on different subnet - will arp for dgw
A point to point port type but the neighboring device runs traditional 802.1D STP

36. How does uplinkfast handle changes in topology?
Round robin - weighted - or host-dependent
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.
Promiscuous and host
The switch checks the MAC and IP reported in the reply against trusted values. If they don't match - it is dropped and logged

37. What is arp throttling?
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
Virtual Router Redundancy Protocol - pretty much the same as HSRP
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
Globally or per-port

38. When should CDP be enabled?
Incoming frames dropped - but MACs learned
80% of the user traffic should stay in the VLAN
It's a router that maintains routes (static or dynamic) - and populates the FIB
Only for trusted Cisco gear - especially phones

39. RSTP BPDU structure
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
A group of wireless devices that share a common SSID
Stateful switchover - redundant sup is fully booted and init'd. Both start and run config are synched as is L2 information - and switchinterfaces.
All ARP packets that arrive on untrusted ports are inspected.

40. What are the 6 HSRP states?
Normal and aggressive
Port with alternative path to root less desirable than root
Discarding - learning - forwarding
Disabled - init - listen - speak - standby - active

41. What are the RSTP port states?
By creating a static IP binding
VTP server for domain null with no password or secure mode
The number of times the CEF table has bee flushed and regenerated as a whole
Discarding - learning - forwarding

42. What is a root link query (RLQ)?
When the size of a cell is intentionally reduced
Half because transmitting and receiving stations use the same frequency
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
TCAM

43. What is the size of ISL encapsulation?
Using a single WAP to centralize access and control over a group of wireless devices.
26-byte header - 4-byte trailer with CRC
An ac adaptor that plugs into a wall outlet.
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs

44. What are the characteristics of the distribution layer?
Promiscuous and host
300 sec by default
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
Priority (class 1)

45. What is the STP disabled state?
Regions and instances
Data and voice over native vlan - no QOS but still uses 802.1p trunk
Admin down
Switchpotrt nonegotiate

46. What is differentiated services model QOS?
When a port moves into forwarding or from fowarding or learning to blocking.
Each network device handles packets individually with no advance reservations
The campus network's backbone
Per VLAN

47. What are the two private vlan association modes?
Each frame transmits its expected duration time
Promiscuous and host
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen

48. What is the SDM?
The distribution layer should have only L3 links
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
1- trunking mode - 2-trunk encapsulation - 3-native VLAN - 4-allowed VLAN
Switching Database Manager - configures and prunes TCAM partitions

49. How many potential links can LACP define?
When a port moves into forwarding or from fowarding or learning to blocking.
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
With the skinny protocol
16 - of which up to 8 are active. The others are in standby

50. How is UDLD configured?
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
Show standby
Transmits keystrokes from phone and commands from CCM
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset