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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. How do you configure IP source guard for hosts that don't use DHCP?
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
By creating a static IP binding
All ARP packets that arrive on untrusted ports are inspected.
Port that connects to another switch and becomes a designated port

2. Whan is a 10GE WAN PHY?
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz
Automatically by duplex mode in use. Full duplex are point ot point. Half duplex ports use traditional 802.1D convergence is used.
All ports where root isn't expected
Connects with SONET or SDH

3. What are the 6 HSRP states?
Group (0-255) - priority (1-254 254 is highest - 100 default)
When a wireless station transmits a frame - the receiving one must send an ack
0000.0c07.acxx where xx is the group number as a 2-digit hex value
Disabled - init - listen - speak - standby - active

4. what must be done on an SVI before it is activated?
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
Flash override (class 4)
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
No shut

5. How much overlap should WAPs have?
L2
Data and voice over native vlan no QOS and no 802.1p trunk
10-15%
Real-time Transport Protocol

6. What is the LACP priority range?
To the virtual port-channel interface
Stateful switchover - redundant sup is fully booted and init'd. Both start and run config are synched as is L2 information - and switchinterfaces.
Critical...used most often for IPT
1-65535 (def 32768) lower priority - higher probability

7. What does IP source guard do?
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
3 seconds. Holdtime =3 hellos + 1

8. What is a topology change?
When a port moves into forwarding or from fowarding or learning to blocking.
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
Cisco ILP and 802.3af
Using a single WAP to centralize access and control over a group of wireless devices.

9. What can the Etherchannel hash use?
Switching Database Manager - configures and prunes TCAM partitions
Based on priority (0-255). Default is 100. Highest IP is tie breaker
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
They disguise the origin of an attack

10. What is the STP learning state?
1-65535 (def 32768) lower priority - higher probability
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
After forwarding delay - port can learn new MAC addresses
A packet can't be switched in hardware with the FIB and must go to the L3 engine

11. What is DSCP codepoint AF41(34)?
Flash override (class 4)
RADIUS
Hashing algorithm
134 bits

12. How is DHCP snooping enabled (scope)?
Globally
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
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

13. How does UDLD work?
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Admin down
No because they only participate if asked

14. What is 802.1x force-authorized?
Distribution layer
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
The port is forced to always authorize any connected client with no authentication necessary (default)
BGP - EIGRP - OSPF - and IS-IS.

15. What is a QoS trust boundary?
10-15%
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
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
Distribution

16. RSTP alternate port
Port with alternative path to root less desirable than root
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
0-255 (lower is better)
Data and voice over native vlan - no QOS but still uses 802.1p trunk

17. How are multiple VLANs mapped to multiple SSIDs?
By using a trunk link
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds

18. RSTP point to point port
Port that connects to another switch and becomes a designated port
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
MAC addresses are learned from the source MAC of incoming frames. If the destination address is unknown - the frame is flooded out all except the receiving port.
Real-time functions such as beacons and probes - encryption and interactions with the client at L2

19. What are the 5 steps to manualy configure STP?
Switches make an effort to move packets as quickly as possible
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
Only when a nonedge port transitions to forwarding
Critical...used most often for IPT

20. What is the STP blocking state?
By using a hash of a key string
Can hear only BDPUs
0000.5e00.01xx
0-65535 (def 32768) lower=better

21. What is DSCP codepoint EF(46)?
To a VLAN and not to a VLAN interface (SVI)
Critical...used most often for IPT
Switching Database Manager - configures and prunes TCAM partitions
The station can transmit immediately and wait for an ack

22. How often are VRRP advertisements sent?
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
The master router can share the VIP
1 second. Backup routers can learn the interval from the master

23. What is the duration time in a wireless frame?
FE and GE
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
Each frame transmits its expected duration time
Route once - switch many

24. What is the VRRP master router?
Turn on port security
The active router. All other routers are in backup state
The topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting

25. How many designated ports are there?
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
Differentiated services
1 per segment
16 - of which up to 8 are active. The others are in standby

26. How does GLBP work?
Use the spanning-tree root macro
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz
Routers are assigned to common GLBP group. All routers can be active and can load balance
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table

27. By default - what layer do catalyst switchports operate on?
Untrusted
L2
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
Local only

28. How does the VRRP master router handle the VIP?
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
16 - of which up to 8 are active. The others are in standby
1 per segment
The master router can share the VIP

29. what I s distributed CEF (dCEF)?
Immediate (class 2)
CEF is distributed completely among multiple L3 forwarding engines.
All fiber-optic links between switches (must be enabled on both ends)
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

30. If you want IP source guard to detect spoofed MAC addresses - what must you do?
Turn on port security
Virtual Router Redundancy Protocol - pretty much the same as HSRP
1 second. Backup routers can learn the interval from the master
Enables portfast - sets the port to access and disables PAgP

31. What types of link can an etherchannel be?
Access or trunk
Only the standby monitors the hello messages from the active router
By default weight is 100. Can be made dynamic per interface
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance

32. How much BW does a PSTN connection use?
Usually QoS from VOIP but not PC dataa
Plain text or md5
By short-circuiting the max age timer
63 kbps

33. How is Root Guard used?
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
On ports where you never expect to find a root bridge for a VLAN
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.

34. How does DSCP handle IP precedence?
L2
Trusted or untrusted
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority
5 classes with 3 drop precedences

35. How is UDLD configured?
Sends a voltage across the receive pairs to detect a 25k ohm resistance
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
The MST instance (MSTI) runs alongside the IST and represents an STP instance
300 sec by default

36. CAM table entries are purged when....
A MAC is seen on a different port
Data goes over native vlan - voice goes over specified VLAN - voice QOS is 802.1p
That they aren't using the same frequencies.
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table

37. What is the range of PAgP channel group numbers?
1 to 64
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
Used when there are 1 or more VLANs mapped to a single STP instance
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive

38. How does the CEF L3 engine operate?

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39. What is UDLD aggressive mode?

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40. What is a wall wart?
Regions and instances
All user ports that have portfast enabled
Incoming frames are dropped (combination of disabled - blocking - and listening)
An ac adaptor that plugs into a wall outlet.

41. What is an IBSS?
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive
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
The wireless clients communicate directly with no other means of connectivity such as a WAP
A packet can't be switched in hardware with the FIB and must go to the L3 engine

42. How long are TCAM masks?
Flash (class 3)
134 bits
Embeds the tag within the frame
Roughly 50%

43. What are the 4 steps to extend QoS trust?
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
1- enable qos - 2-define qos parameters to be trusted - 3-make trust conditional - 4-instruct IP phone how to extnd boundary
Needs hardware upgrade over WEP - uses AES encryption
Incoming frames dropped - but MACs learned

44. Can ARP replies be checked
Receives the first packet of a traffic flow and routes it
Yes
No
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root

45. What are the gotchas for uplinkfast?

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46. What is an ESS?
When the AP uplinks to an Ethernet network.
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains
10-15%
Between interfaces that are assigned to L2 VLANs or L2 trunks

47. What are the steps to configure a PAgP port channel?
By name - config revision - and instance to vlan mapping table
Trusted or untrusted
A host port goes up or down
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode

48. Where is bdpu guard enabled?
A group of wireless devices that share a common SSID
The topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding
All user ports that have portfast enabled
When each AP stands alone within the larger network.

49. What does BDPU filtering do?
Effectively stops STP on filtered ports
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.
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
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

50. How does RSTP identify a topology change?
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
Only when a nonedge port transitions to forwarding
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack