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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 is the GLBP redirect timer?
Needs hardware upgrade over WEP - uses AES encryption
Differentiated services code point
The link status stays up - but something between them has failed or is filtering traffic
Determines when the AVG will stop using the old VMAC in ARP replies

2. If a port is configured for errdisable auto recovery - how long does it stay down?
300 sec by default
2 - one for control messages and one for data
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string

3. 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
Based on priority (0-255). Default is 100. Highest IP is tie breaker
Receives the first packet of a traffic flow and routes it
Up to 4 can be used in a group. Called active virtual forwarders (AVF)

4. What is the STP forwarding state?
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
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.
Time between BDPUs sent by root bridge. Default of 2 seconds

5. can root guard and bdpu guard be used together?
Only for the offending VLAN on the port
Will trunk if asked
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
No

6. What is the STP learning state?
Yes
After forwarding delay - port can learn new MAC addresses
That they aren't using the same frequencies.
Untrusted

7. Can two switches in the auto(PAgP) or passive (LACP) mode create a channel? Why?
No because they only participate if asked
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
0-65535 (def 32768) lower=better
Once the CCM gives them the parameters - they use RTP

8. what if a secondary VLAN?
0-255 (lower is better)
802.1w
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
Effectively stops STP on filtered ports

9. if the switchport is part of an etherchannel - Where is the network assigned
Manages addition - deletion and renaming VLANs across the network
2 seconds
A MAC is seen on a different port
To the virtual port-channel interface

10. RSTP alternate port
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
For hosts that doesn't understand routing - the DGW is configured to reply with its own mac
Configure non-silent submode
Port with alternative path to root less desirable than root

11. EAP encryption
Dynamic WEP keys that change periodically
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
The DCF interframe space- the random backoff time before a wireless set can transmit

12. What are the 5 steps to manualy configure STP?
Use the spanning-tree root macro
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
By configuring every switch port to have an expected and controlled behavior
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root

13. What is the PVLAN promiscuous mode?
The switch checks the MAC and IP reported in the reply against trusted values. If they don't match - it is dropped and logged
Connects to a router - firewall - or gateway. Can communicate with anything else connected to the primary or any secondary. Ignores pvlan config
By using a hash of a key string
Dynamic WEP keys that change periodically

14. What is the SDM?
Src-dst-ip
Yes
Another router must have a higher HSRP priority and have preemt set up
Switching Database Manager - configures and prunes TCAM partitions

15. What is 802.1x force-unauthorized?
Port is forced to never authorize any connected client
Prevents the dhcp binding DB from being checked.
2 strand MMF with MT-RJ or SC connectors
Using a single WAP to centralize access and control over a group of wireless devices.

16. How do you configure IP source guard for hosts that don't use DHCP?
Manually
By creating a static IP binding
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority
Disabled - init - listen - speak - standby - active

17. What feedback mechanism does wireless use?
By using an Ether-IP tunnel
Access or trunk
Etherchannel ports have inconsistent config
When a wireless station transmits a frame - the receiving one must send an ack

18. What cabling do GBICs use?
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
Flash (class 3)
SC fiber or RJ-45
Using a mobility exchange message

19. Where should you change the network diameter value?
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
Single instance of STP for all VLANs. BDPUs are sent over trunks using the native VLAN with untagged frames. Dot1q based
Cisco recommends only on the root bridge
By short-circuiting the max age timer

20. What are the 6 HSRP states?
Single instance of STP for all VLANs. BDPUs are sent over trunks using the native VLAN with untagged frames. Dot1q based
0-255
Disabled - init - listen - speak - standby - active
An ac adaptor that plugs into a wall outlet.

21. What is the port number range?
Control functions
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
0-255
A VLAN that spans the entire fabric

22. At what layer should the WLC be connected?
Distribution
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
RPR - RPR+ - and SSO
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added

23. What are the 4 steps in DHCP negotiation?
The total delay from start to finish
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack
Value - mask - and result (VMR) combinations
Globally

24. What address does HSRP send hello packets to?
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
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
802.1D
224.0.0.2 (all routers)

25. What are the steps to configure a PAgP port channel?
All ARP packets that arrive on untrusted ports are inspected.
2 - one for control messages and one for data
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS

26. Can MSTP interoperate with 802.1q and/or PVST+?
Yes to both
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
The active router. All other routers are in backup state
The station can transmit immediately and wait for an ack

27. What does the minimum keyword do in HSRP?
Port stays up - packets from violating MACs dropped - no logging
Forces the router to wait for a period of time before attempting overthrow
900 MHz - 2.4Ghz - and 5-6GHz
Globally

28. How do IP phones communicate with each other?
An AP's coverage area
Access or trunk
Once the CCM gives them the parameters - they use RTP
Bridge priority and MAC

29. What is Per VLAN STP (PVST)?
Route once - switch many
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
Data and voice over native vlan - no QOS but still uses 802.1p trunk
No

30. What are dynamic VLANs based on?
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string
Matching SSID - compatible data rate - authentication credentials
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
MAC of the end device

31. If a wireless station needs to transmit and no other device is transmitting - what happens?
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
Change in trunk encap
The station can transmit immediately and wait for an ack
It is enabled by default on all CEF capable switches

32. What is a wireless mobility group?
Globally
10-15%
A client can roam to any WLC as long as it stays in a mobility group
A MAC is seen on a different port

33. What is the FM?
Automatically using DTP and CDP
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
300 sec
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers

34. What is the STP hello timer?
Differentiated services code point
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
2-8 FE - GE - or 10GE are bundled.
Time between BDPUs sent by root bridge. Default of 2 seconds

35. RSTP edge port
Only a single host connects . If one BDPU is received - it is no longer an edge port
Roughly 50%
Group (0-255) - priority (1-254 254 is highest - 100 default)
Differentiated services code point

36. What is best effort delivery QOS?
L2
The frame tag contains a 3 but portion tagged from 0 (low) to 7 (high)
Switches make an effort to move packets as quickly as possible
A packet can't be switched in hardware with the FIB and must go to the L3 engine

37. What is DSCP?
VTP server for domain null with no password or secure mode
Differentiated services code point
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
Trusted or untrusted

38. What can the Etherchannel hash use?
Isolated and community
Limits the number if dhcp requests on a port
By brining up a tunnel between them to carry 802.11 related messages and client data.
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers

39. When should CDP be enabled?
Roughly 50%
Only for trusted Cisco gear - especially phones
A host port goes up or down
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs

40. What does the static keyword do when applying an arp ACL?
A single broadcast domain
Manually
Flash (class 3)
Prevents the dhcp binding DB from being checked.

41. How is UDLD configured?
A MAC is seen on a different port
By creating a static IP binding
Reboots and searches for a new WLC
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports

42. What is an IST instance?
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
To the virtual port-channel interface
By default weight is 100. Can be made dynamic per interface
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.

43. How are errdisable triggers tuned?
Embeds the tag within the frame
Globally
2 - one for control messages and one for data
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode

44. Define GLBP
Gateway load balancing protocol - cisco proprietary
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
An L2 switch can only forward frames best effort unless going across a trunk
134 bits

45. What is the DIFS?
Connects to a router - firewall - or gateway. Can communicate with anything else connected to the primary or any secondary. Ignores pvlan config
BGP - EIGRP - OSPF - and IS-IS.
The DCF interframe space- the random backoff time before a wireless set can transmit
Needs hardware upgrade over WEP - uses AES encryption

46. How does every GLBP command begin
Switch(config-if)# glbp xx where xx = group number
Only when a nonedge port transitions to forwarding
Packets must be sent to the L3 engine for further processing
It is enabled by default on all CEF capable switches

47. What are the steps to configure a LACP port channel?
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
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
Critical...used most often for IPT
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority

48. How can BDPU Guard be configured?
The port asks the other end to trunk
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance
16 bits (8b port priority - 8b port number)
Globally or per-port

49. What must be supported for port-based security to occur?
Each frame transmits its expected duration time
1 second. Backup routers can learn the interval from the master
The TOS field in the header is used. 2 methods 3 bits or 6 bits
802.1x with EAP over LAN (EAPOL)

50. What are the two etherchannel negotiation protocols?
3 seconds. Holdtime =3 hellos + 1
Trunk
Using a mobility exchange message
PAgP (Cisco proprietary) and LACP (standards-based)