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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 port number range?
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
0-255
FIB

2. What are the 3 unlicensed frequencies?
When a port moves into forwarding or from fowarding or learning to blocking.
900 MHz - 2.4Ghz - and 5-6GHz
1-1005 (1 and 1002-1005 are reserved)
If the switch or the powered device doesn't suport power class discovery

3. What are the 2 choices for VLANs with IPT?
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset
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
Stateful switchover - redundant sup is fully booted and init'd. Both start and run config are synched as is L2 information - and switchinterfaces.
They must be carried over a voice VLAN (VVID) or over a regular data VLAN (ie. The native VLAN or the PVID)

4. What are the 3 trunk switchport modes?
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
A key string of up to 8 characters is sent. Default is cisco.
Trunk - dynamic auto - dynamic desireable (default)
By short-circuiting the max age timer

5. Does VTP pass private VLAN configuration?
Roughly 50%
No
Trunk
Usually QoS from VOIP but not PC dataa

6. What is jitter?
Each frame transmits its expected duration time
Must be same type - speed - VLAN(s) - native vlan - pass the same set of vlans -duplex - and spanning tree settings
FIB
Variation in delay

7. If a port is configured for errdisable auto recovery - how long does it stay down?
Control functions
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz
300 sec by default
Option 43

8. How doed backbonefast work?
By sending a gratuitous ARP
By short-circuiting the max age timer
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
Globally

9. How is a QoS trust bondary configured?
Every switch and router in a network must be configured with appropriate QoS features and policies
Will trunk if asked
Using a mobility exchange message
Collision domain

10. What is an ESS?
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
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
L2
When the AP uplinks to an Ethernet network.

11. What are the characteristics of the access layer?
Any ports associated with an isolated vlan can reach the primary - but not any other secondary. Hosts withn an isolated vlan can't reach each other
2 seconds
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
A point to point port type

12. What does Root Guard do?
Controls where candidate root bridges can be connected and found on a network
By name - config revision - and instance to vlan mapping table
With portfast
When the AP uplinks to an Ethernet network.

13. Where shoul dmultilayer switches be implemented?
Distribution layer
An L2 switch can only forward frames best effort unless going across a trunk
Flash override (class 4)
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information

14. What does the standby HSRP router do?
MAC of the end device
Value - mask - and result (VMR) combinations
Only the standby monitors the hello messages from the active router
Per VLAN

15. What address does HSRP send hello packets to?
Full duplex
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
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
224.0.0.2 (all routers)

16. How does an L2 switch do QOS?
Automatically negotiates a common trunk mode between switches
An L2 switch can only forward frames best effort unless going across a trunk
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority
Determines when the AVG will stop using the old VMAC in ARP replies

17. How does ISL do trunking?
Every switch and router in a network must be configured with appropriate QoS features and policies
1 IP subnet
By encapsulating each frame in a header and trailer
A packet can't be switched in hardware with the FIB and must go to the L3 engine

18. Can two switches in the auto(PAgP) or passive (LACP) mode create a channel? Why?
All fiber-optic links between switches (must be enabled on both ends)
Port with best root path cost on segment
On the left as you face the connector
No because they only participate if asked

19. What is a discard adjacency?
Can send and receive BDPUs
Packets are discarded due to an ACL or policy action
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
Up to 4 can be used in a group. Called active virtual forwarders (AVF)

20. How do VRRP routers handle preemption?
On by default
The number of times the CEF table has bee flushed and regenerated as a whole
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
Port with redundant - but less deisrable connection to a segment. Possibly root candidate

21. How can you load-balance with HSRP?
Used when there are 1 or more VLANs mapped to a single STP instance
Sends a voltage across the receive pairs to detect a 25k ohm resistance
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
SC fiber or RJ-45

22. How is UDLD configured?
2 seconds
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
If the switch or the powered device doesn't suport power class discovery
The station can transmit immediately and wait for an ack

23. What is DSCP?
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
Best effort delivery - integrated services model - and differentiated services model
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
Differentiated services code point

24. What is an untrusted port under dhcp snooping?
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
No
Based on priority (0-255). Default is 100. Highest IP is tie breaker
Regions and instances

25. What does the RP do?
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance
By encapsulating each frame in a header and trailer
By using a hash of a key string
Receives the first packet of a traffic flow and routes it

26. By default - what layer do catalyst switchports operate on?
Port
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
By sending a gratuitous ARP
L2

27. How is root port decided upon?
A point to point port type
Only for the offending VLAN on the port
Lowest cumulative cost to root
All L2 connectivity should be contained within the access layer.

28. How does IPT behave when the voice VLAN is in untagged mode?
CEF is distributed completely among multiple L3 forwarding engines.
Data and voice over native vlan - no QOS but still uses 802.1p trunk
80% of the user traffic should stay in the VLAN
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN

29. what should you do if you expect a PAgP capable switch at the other end vs. a server or host?
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
Configure non-silent submode
The number of times the entry has been updated since the table was generated
Isolated and community

30. What is errdisable pagp-flap?
Must be same type - speed - VLAN(s) - native vlan - pass the same set of vlans -duplex - and spanning tree settings
0-255 (lower is better)
Etherchannel ports have inconsistent config
Prevents the dhcp binding DB from being checked.

31. What is a wall wart?
An ac adaptor that plugs into a wall outlet.
By using a trunk link
On ports where you never expect to find a root bridge for a VLAN
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information

32. How does every VRRP command begin?
Only for the offending VLAN on the port
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
Switch(config-if)# vrrp xx where xx= group number
Port stays up - packets from violating MACs dropped - no logging

33. What does the reload keyword do in HSRP?
Lowest cumulative cost to root
Switching Database Manager - configures and prunes TCAM partitions
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
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

34. Where are security and QoS ACLs stored?
Discarding - learning - forwarding
Because each frame is checked
Needs hardware upgrade over WEP - uses AES encryption
TCAM

35. What is a CEF glean?

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36. What is the size of ISL encapsulation?
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
26-byte header - 4-byte trailer with CRC
On the left as you face the connector
With portfast

37. How is RSTP synchronization accomplished?
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
The number of times the CEF table has bee flushed and regenerated as a whole
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
Isolated and community

38. 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
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
LWAPP (Cisco proprietary) and CAP-WAP (standards based)

39. What do you need to determine to use MSTP?
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance
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
FIB
Each network device handles packets individually with no advance reservations

40. What is portfast?
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
Almost eliminates listening and learning states for single hosts on an access link
By default weight is 100. Can be made dynamic per interface
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added

41. What if RSTP BDPUs aren't received?
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode
Globally
Will trunk if asked

42. What is an indirect topology change?
The link status stays up - but something between them has failed or is filtering traffic
A client can roam to any WLC as long as it stays in a mobility group
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
By name - config revision - and instance to vlan mapping table

43. What does MSTP do?
Used when there are 1 or more VLANs mapped to a single STP instance
An L2 switch can only forward frames best effort unless going across a trunk
Port is forced to never authorize any connected client
The port is forced to always authorize any connected client with no authentication necessary (default)

44. WPA2 encryption
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string
Packets are discarded due to an ACL or policy action
26-byte header - 4-byte trailer with CRC
Needs hardware upgrade over WEP - uses AES encryption

45. How do you configure DAI for statically configured IP addresses?
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
Variation in delay
A host port goes up or down
By an ARP access list that defines the permitted bindings

46. What are the 2 power over ethernet methods?
A MAC is seen on a different port
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
One that can be detected on a switch interface (ie. Up/down)
Cisco ILP and 802.3af

47. How does 802.3af do power discovery?
Almost eliminates listening and learning states for single hosts on an access link
Can send and receive BDPUs
Value - mask - and result (VMR) combinations
Sends a voltage across the receive pairs to detect a 25k ohm resistance

48. What is UDLD normal mode?
Needs hardware upgrade over WEP - uses AES encryption
By using an Ether-IP tunnel
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated

49. What are 2 ways to configure VLAN and VTP information?
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
The ASIC
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy
Routers are assigned to common GLBP group. All routers can be active and can load balance

50. What is an IST instance?
Port stays up - packets from violating MACs dropped - no logging
12 kbps with headers and compression
5 classes with 3 drop precedences
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.