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CCNP Switch Deck

Instructions:

Answer 50 questions in 15 minutes.
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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 does Root Guard do?
Configure non-silent submode
Controls where candidate root bridges can be connected and found on a network
Root
224.0.0.2 (all routers)

2. If a wireless station needs to transmit and no other device is transmitting - what happens?
An AP's coverage area
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
Real-time Transport Protocol
The station can transmit immediately and wait for an ack

3. What are the 5 steps a LAP uses to establish communication with a WLC?
Port that connects to another switch and becomes a designated port
Prevents the dhcp binding DB from being checked.
Immediate (class 2)
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

4. What is step 1 of enabling IP source guard?
One that can be detected on a switch interface (ie. Up/down)
Configure and enable DHCP snooping
Collision domain
By name - config revision - and instance to vlan mapping table

5. What are the three basic types of QOS?
Should be used on access switches - can't be used on root - keeps enabled switch from becoming root by raising priority of switch and all ports - making them undesirable
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
Best effort delivery - integrated services model - and differentiated services model
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD

6. If the WLC connects to an Etherchannel - how should the channel be configured and why?

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7. What is DSCP codepoint AF41(34)?
By creating a static IP binding
Flash override (class 4)
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
If the switch or the powered device doesn't suport power class discovery

8. What is the size of ISL encapsulation?
By creating a static IP binding
26-byte header - 4-byte trailer with CRC
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode

9. Define VRRP
RPR - RPR+ - and SSO
Virtual Router Redundancy Protocol - pretty much the same as HSRP
7 switches from root bridge
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds

10. How many 802.3af power classes are there?
0-65535 (def 32768) lower=better
Yes
5 (0-4 with 4 being the highest)
On by default

11. What is an autonomous mode AP?
When each AP stands alone within the larger network.
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
300 sec
Protects STP when a physical malfunction only allows traffic in 1 direction - even though the link shows as up (cisco proprietary)

12. What is the GLBP AVG?
19
Port is forced to never authorize any connected client
Only for the offending VLAN on the port
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

13. What does the SP do?
Reboots and searches for a new WLC
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
Use the spanning-tree root macro
As a VLAN access map

14. What can cause a wireless client to switch between Aps?
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
0000.5e00.01xx
Usually QoS from VOIP but not PC dataa
To a VLAN and not to a VLAN interface (SVI)

15. What does MSTP do?
Used when there are 1 or more VLANs mapped to a single STP instance
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
Between interfaces that are assigned to L2 VLANs or L2 trunks
SC fiber or RJ-45

16. What is the cost of a 10Gbps link?
By brining up a tunnel between them to carry 802.11 related messages and client data.
2 seconds (def)
FIB
2

17. What is latency?
Arp for local subnet - if on different subnet - will arp for dgw
Access or trunk
Roughly 2000
The total delay from start to finish

18. What is the STP hello timer?
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz
Time between BDPUs sent by root bridge. Default of 2 seconds

19. How is DHCP snooping enabled (scope)?
Determines when the AVG will stop using the old VMAC in ARP replies
The MST instance (MSTI) runs alongside the IST and represents an STP instance
Globally
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links

20. What is the PVLAN promiscuous mode?
The active router. All other routers are in backup state
Using a single WAP to centralize access and control over a group of wireless devices.
Port stays up - packets from violating MACs dropped - no logging
Connects to a router - firewall - or gateway. Can communicate with anything else connected to the primary or any secondary. Ignores pvlan config

21. How does HSRP do MD5 authentication?
80% of the user traffic should stay in the VLAN
2
By using an Ether-IP tunnel
By using a hash of a key string

22. RSTP root port
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
Port with best root path cost
On the left as you face the connector

23. What is a cell?

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24. How do you renable an err-disable port by default?
When the AP uplinks to an Ethernet network.
MST attributes must be manually entereed on each switch in the region. They don' t propagate like VTP.
Used when there are 1 or more VLANs mapped to a single STP instance
Manually

25. What is topology-basec caching?
The topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding
TCAM
Effectively stops STP on filtered ports
If the switch or the powered device doesn't suport power class discovery

26. What is the default network diameter?
Manually
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry
PAgP (Cisco proprietary) and LACP (standards-based)
7 switches from root bridge

27. How does the VRRP master router handle the VIP?
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
The master router can share the VIP
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting

28. What are the 2 types of secondary VLAN?
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
Two distribution switches that aggregate one or more access switches
Isolated and community
Edge - root - and point to point

29. How does DSCP handle IP precedence?
No
Either desirable or auto mode
1500B
5 classes with 3 drop precedences

30. What is dynamic auto?
Root - designated - blocking - alternate - forwarding (host)
Cisco ILP and 802.3af
Trusted ports
Will trunk if asked

31. static vlans offer ____ based membership
Port
A client can roam to any WLC as long as it stays in a mobility group
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS

32. What is a drop adjacency?

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33. How can you tell if a switch block is too large?
Can hear only BDPUs
Data and voice over native vlan - no QOS but still uses 802.1p trunk
Real-time Transport Protocol
Routers at the distribution layer become the bottlenecks or broadcast or multicast traffic slows the switches in the switch block

34. What does port-security protect do?
Port stays up - packets from violating MACs dropped - no logging
Sends a voltage across the receive pairs to detect a 25k ohm resistance
To a VLAN and not to a VLAN interface (SVI)
Normal and aggressive

35. How is an RSTP edge port configured
With portfast
Edge - root - and point to point
Embeds the tag within the frame
The port asks the other end to trunk

36. What is dynamic desireable?
The configureable UDLD interval must be less than max age plus two intervals of forward delay
1-65535 (def 32768) lower priority - higher probability
The port asks the other end to trunk
Switch(config-if)# vrrp xx where xx= group number

37. what I s distributed CEF (dCEF)?
Trunk
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
Half because transmitting and receiving stations use the same frequency
CEF is distributed completely among multiple L3 forwarding engines.

38. How do Cisco IP phones communicate with the CCM?
Port with best root path cost
The time that a port spends in both listening and learning states . Default 15 seconds
With the skinny protocol
Used to switch packets destined for the null interface

39. How much BW does a voip connection use?
No
All L2 connectivity should be contained within the access layer.
CEF is distributed completely among multiple L3 forwarding engines.
12 kbps with headers and compression

40. Whan is a 10GE WAN PHY?
0-255
802.1x with EAP over LAN (EAPOL)
Connects with SONET or SDH
Admin down

41. If a wireless station needs to transmit and another device is transmitting - what happens?
The wireless clients communicate directly with no other means of connectivity such as a WAP
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
Route once - switch many
The RP listens to a flow's 1st packet for the dest. The SE listens to the packet and dest and puts a shortcut in the MSL cache. Netflow switching - route once - switch many

42. What is BDPU Guard?
Trunk - dynamic auto - dynamic desireable (default)
If any BDUP is received on a port - it puts the port into the errdisable state
RPR - RPR+ - and SSO
A packet can't be switched in hardware with the FIB and must go to the L3 engine

43. How do you disable DTP when you configure both ends of the ISL manually?
Switchpotrt nonegotiate
Within a single MST region - an IST instances runs to work out a loop free topology between links where CST meets the region boundary and all switches in the region. It runs at the boundary.
802.11
802.1w

44. What is the range of PAgP channel group numbers?
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
They disguise the origin of an attack
FIB
1 to 64

45. How is Root Guard used?
Protects STP when a physical malfunction only allows traffic in 1 direction - even though the link shows as up (cisco proprietary)
On ports where you never expect to find a root bridge for a VLAN
0000.0c07.acxx where xx is the group number as a 2-digit hex value
Promiscuous and host

46. How is UDLD configured?
Use sh interface on the interface and look for error counts > 10
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
A MAC is seen on a different port
Only for trusted Cisco gear - especially phones

47. can root guard and bdpu guard be used together?
Incoming frames are dropped (combination of disabled - blocking - and listening)
No
When a port moves into forwarding or from fowarding or learning to blocking.
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

48. How do you prevent VLAN hopping?
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
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
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
Set the native VLAN of a trunk to a bogus or unused VLAN ID then prune the native VLAN off both ends of the trunk

49. What is differentiated services model QOS?
Each network device handles packets individually with no advance reservations
Between any type of interface as long as the interface can have an L3 address assigned
Globally
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets

50. How does uplinkfast handle changes in topology?
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
By an ARP access list that defines the permitted bindings
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.
TCAM