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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 can cause a wireless client to switch between Aps?
Cisco recommends only on the root bridge
Packets must be sent to the L3 engine for further processing
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD

2. What does the reload keyword do in HSRP?
Each network device handles packets individually with no advance reservations
Change in trunk encap
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
Real-time functions such as beacons and probes - encryption and interactions with the client at L2

3. What is errdisable pagp-flap?
Etherchannel ports have inconsistent config
They disguise the origin of an attack
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)

4. How do you configure a DHCP gateway?
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
16 bits (8b port priority - 8b port number)
Round robin - weighted - or host-dependent
Both layer 2 switching and IVR

5. What is UDLD aggressive mode?

6. What types of link can an etherchannel be?
Access or trunk
Virtual Router Redundancy Protocol - pretty much the same as HSRP
Per VLAN
Used when ACLs specify port ranges...used by TCAM

7. How often are CAM table entries aged?
Flash (class 3)
Two distribution switches that aggregate one or more access switches
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
300 sec

8. How does a DAI enabled switch gather trusted ARP info?
Effectively stops STP on filtered ports
Virtual Router Redundancy Protocol - pretty much the same as HSRP
From the DHCP snooping database or from static entries
Those that connect to other switches

9. Define VRRP
Only the standby monitors the hello messages from the active router
Multicasts to 224.0.0.18 (VRRP)
Virtual Router Redundancy Protocol - pretty much the same as HSRP
Effectively stops STP on filtered ports

10. What is a topology change?
Port with alternative path to root less desirable than root
When a port moves into forwarding or from fowarding or learning to blocking.
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
Port that connects to another switch and becomes a designated port

11. What is differentiated services model QOS?
Edge - root - and point to point
Embeds the tag within the frame
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy
Each network device handles packets individually with no advance reservations

12. RSTP edge port
Plain text or md5
All user ports that have portfast enabled
All nondesignated ports - but ok for all ports
Only a single host connects . If one BDPU is received - it is no longer an edge port

13. What is an SVI?
Trunk - dynamic auto - dynamic desireable (default)
Each network device handles packets individually with no advance reservations
Frames are forwarded
Switched Virtual Interface - an L3 address can be assigned to a logical interface that represents an entire VLAN - which becomes the DGW for that VLAN

14. How much overlap should a wireless repeater have?
Differentiated services code point
Roughly 50%
19
By brining up a tunnel between them to carry 802.11 related messages and client data.

15. can root guard and udld be used together?
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance
Immediate (class 2)
Incoming frames are dropped (combination of disabled - blocking - and listening)
Yes

16. What feedback mechanism does wireless use?
The same as a standby group in HSRP
When a wireless station transmits a frame - the receiving one must send an ack
L2
Distribution layer

17. How are VACLs applied
To a VLAN and not to a VLAN interface (SVI)
300 sec
2 - one for control messages and one for data
0000.5e00.01xx

18. How are multiple VLANs mapped to multiple SSIDs?
1 IP subnet
No
By using a trunk link
L2

19. RSTP alternate port
Port with alternative path to root less desirable than root
Root
Incoming frames dropped - but MACs learned
Cisco recommends only on the root bridge

20. What is the size of ISL encapsulation?
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
26-byte header - 4-byte trailer with CRC
Port that connects to another switch and becomes a designated port
Dynamic arp inspection

21. What is the STP forward delay timer?
On root - because the root bridge propagates timers with config BDPU
The distribution layer should have only L3 links
The time that a port spends in both listening and learning states . Default 15 seconds
Use sh interface on the interface and look for error counts > 10

22. How many users should be within a switch block?
Roughly 2000
It's a router that maintains routes (static or dynamic) - and populates the FIB
1-1005 (1 and 1002-1005 are reserved)
To a VLAN and not to a VLAN interface (SVI)

23. What does VTP do?
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
Manages addition - deletion and renaming VLANs across the network
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
No

24. What are the steps to configure a LACP port channel?
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority
Only for the offending VLAN on the port
16 bits (8b port priority - 8b port number)
0-255

25. Where does layer switching occur?
1-1005 (1 and 1002-1005 are reserved)
Between any type of interface as long as the interface can have an L3 address assigned
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec

26. How does loop guard block ports?
224.0.0.2 (all routers)
Only for the offending VLAN on the port
Access
By an ARP access list that defines the permitted bindings

27. How many virtual MACs can GLBP have?
The port asks the other end to trunk
Automatically by duplex mode in use. Full duplex are point ot point. Half duplex ports use traditional 802.1D convergence is used.
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
By using a trunk link

28. What is RPR?
26-byte header - 4-byte trailer with CRC
Every switch and router in a network must be configured with appropriate QoS features and policies
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
With portfast

29. How can you load-balance with HSRP?
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
2 strand MMF with MT-RJ or SC connectors
By name - config revision - and instance to vlan mapping table
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each

30. 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
Dynamic WEP keys that change periodically
Differentiated services
Port with best root path cost on segment

31. What are the 2 types of BDPU?
Using a single WAP to centralize access and control over a group of wireless devices.
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
All nondesignated ports - but ok for all ports
Configuration and TCN

32. Can two switches in the auto(PAgP) or passive (LACP) mode create a channel? Why?
By an ARP access list that defines the permitted bindings
No because they only participate if asked
1 per segment
Routers are assigned to common GLBP group. All routers can be active and can load balance

33. What is DSCP codepoint AF31(26)?
1 per segment
A client can roam to any WLC as long as it stays in a mobility group
LACP port priority
Flash (class 3)

34. What is DAI?
Dynamic arp inspection
Value - mask - and result (VMR) combinations
Root
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

35. What is the VRRP skew time?
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
The switch checks the MAC and IP reported in the reply against trusted values. If they don't match - it is dropped and logged
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
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.

36. How is a QoS trust bondary configured?
Option 43
Trusted or untrusted
Switch(config-if)# vrrp xx where xx= group number
Every switch and router in a network must be configured with appropriate QoS features and policies

37. What functions does a WLC perform?
Packets must be sent to the L3 engine for further processing
Control functions
Those that connect to other switches
Full duplex

38. How are frames forwarded across a specific link?
Per VLAN
Hashing algorithm
Distributed coordinion function - the use of timers to prevent wireless collisions
Configure and enable DHCP snooping

39. What are the VRRP group and priority numbers?
Once the CCM gives them the parameters - they use RTP
Group (0-255) - priority (1-254 254 is highest - 100 default)
4
Two distribution switches that aggregate one or more access switches

40. How many 802.3af power classes are there?
Checks the sender's ip in all arp requests and checks the sender's IP against target IP in all replies
The standby becomes active and stays active by default. Preemption can be configured
The ASIC
5 (0-4 with 4 being the highest)

41. What duplex setting does 802.11 use and why?
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
Group (0-255) - priority (1-254 254 is highest - 100 default)
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.
Half because transmitting and receiving stations use the same frequency

42. What are the characteristics of the core layer
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
Differentiated services
LACP port priority
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS

43. How does DSCP handle IP precedence?
Differentiated services code point
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack
5 classes with 3 drop precedences
That they aren't using the same frequencies.

44. How is RSTP synchronization accomplished?
Matching SSID - compatible data rate - authentication credentials
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
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
Access

45. What does Loop Guard do?
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz
802.1D
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
16 - of which up to 8 are active. The others are in standby

46. FE connectors use...
Another router must have a higher HSRP priority and have preemt set up
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
12 kbps with headers and compression
2 strand MMF with MT-RJ or SC connectors

47. What is the STP learning state?
By configuring every switch port to have an expected and controlled behavior
Port with best root path cost
After forwarding delay - port can learn new MAC addresses
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology

48. How do VRRP routers handle preemption?
Turn on port security
On by default
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
The ASIC

49. What is Per VLAN STP (PVST)?
Distribution
Completed dhcp bindings - mac addresses - IP addresses - etc.
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.
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q

50. In a converged fabric - which switch(es) send config BDPUs?
Root
Matching SSID - compatible data rate - authentication credentials
1-1005 (1 and 1002-1005 are reserved)
Variation in delay