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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. How does a DHCP server send WLC addresses?
Full duplex
Prevents the dhcp binding DB from being checked.
It can't
Option 43

2. What is errdisable pagp-flap?
1- enable qos - 2-define qos parameters to be trusted - 3-make trust conditional - 4-instruct IP phone how to extnd boundary
Etherchannel ports have inconsistent config
Isl - dot1q - negotiate (default)
BGP - EIGRP - OSPF - and IS-IS.

3. WPA2 encryption
Needs hardware upgrade over WEP - uses AES encryption
Isolated and community
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
Real-time functions such as beacons and probes - encryption and interactions with the client at L2

4. How is 802.1x configured for port security?
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
Disabled - blocking - listening - learning - forwarding
RADIUS
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

5. How does a LAP and a WLC authenticate between each other?
A private VLAN can be logically associated with a special secondary vlan
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
7 switches from root bridge
Using digital certificates

6. What is a topology change?
When a port moves into forwarding or from fowarding or learning to blocking.
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset
0-255
By using an Ether-IP tunnel

7. How does IPT behave when the voce VLAN is in the default none mode?
Data and voice over native vlan no QOS and no 802.1p trunk
10-15%
The switch checks the MAC and IP reported in the reply against trusted values. If they don't match - it is dropped and logged
1/2 and 3/6

8. What is DSCP codepoint AF21(18)?
Can hear only BDPUs
LACP port priority
Immediate (class 2)
All ports where root isn't expected

9. What are LOU register pairs?
Normal and aggressive
Both ends should be on because on modes doesn't send PAgP or LACP packets
Group (0-1023) priority (1-255 higher better def 100)
Used when ACLs specify port ranges...used by TCAM

10. What is an MST instance?
Roughly 50%
63 kbps
The MST instance (MSTI) runs alongside the IST and represents an STP instance
Trunk

11. What are the steps to configure MST?
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
Distribution layer
Matching SSID - compatible data rate - authentication credentials
L2

12. What is a VRRP group?
The same as a standby group in HSRP
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
2
Configuration and TCN

13. What is a null adjacency?
BGP - EIGRP - OSPF - and IS-IS.
Used to switch packets destined for the null interface
Bridge priority and MAC
LWAPP (Cisco proprietary) and CAP-WAP (standards based)

14. How much BW does a PSTN connection use?
63 kbps
Cisco ILP and 802.3af
Root - designated - alternate - and backup
The frame tag contains a 3 but portion tagged from 0 (low) to 7 (high)

15. What are the characteristics of the core layer
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
By default weight is 100. Can be made dynamic per interface
Only when a nonedge port transitions to forwarding
0-255 (lower is better)

16. What is a microcell?
Both layer 2 switching and IVR
When the size of a cell is intentionally reduced
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
RADIUS

17. What is a service set?
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority
Checks the destination MAC in the header against the target MAC in the ARP reply
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p
A group of wireless devices that share a common SSID

18. What is route caching?

19. What does MSTP do?
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
Only for trusted Cisco gear - especially phones
Used when there are 1 or more VLANs mapped to a single STP instance
Switch(config-if)# standby xx where x= group number

20. What is PVST plus (PVST+)?
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
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
The ASIC
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL

21. Where does layer switching occur?
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
Used when there are 1 or more VLANs mapped to a single STP instance
Multicasts to 224.0.0.18 (VRRP)
Between any type of interface as long as the interface can have an L3 address assigned

22. Where should STP timers be configured and why?
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz
Switch(config-if)# vrrp xx where xx= group number
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
On root - because the root bridge propagates timers with config BDPU

23. When a host is connected to a switchport - why aren't frame errors propagated?
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
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
Because each frame is checked
Port with best root path cost

24. What is the GLBP AVG?
Switching Database Manager - configures and prunes TCAM partitions
1 IP subnet
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
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

25. How does the CEF L3 engine operate?

26. What is an end to end vlan?
If a unidirectional link is detected - the switch doesn't try to reestablish the link. ULD msgs are sent once/sec for 8 seconds - then the port is err-disabled
The number of times the CEF table has bee flushed and regenerated as a whole
Etherchannel ports have inconsistent config
A VLAN that spans the entire fabric

27. 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
By encapsulating each frame in a header and trailer
By using a trunk link
On ports where you never expect to find a root bridge for a VLAN

28. If a wireless station needs to transmit and another device is transmitting - what happens?
By brining up a tunnel between them to carry 802.11 related messages and client data.
Can hear only BDPUs
Local only
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting

29. What are the steps to configure a PAgP port channel?
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode
BGP - EIGRP - OSPF - and IS-IS.
Trusted or untrusted
Roughly 50%

30. What is the DIFS?
Variation in delay
The DCF interframe space- the random backoff time before a wireless set can transmit
Src-dst-ip
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

31. How is an instance defined?
They disguise the origin of an attack
The link status stays up - but something between them has failed or is filtering traffic
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
By name - config revision - and instance to vlan mapping table

32. What is a direct topology change?
Data and voice over native vlan - no QOS but still uses 802.1p trunk
One that can be detected on a switch interface (ie. Up/down)
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
Globally

33. RSTP edge port
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
Only a single host connects . If one BDPU is received - it is no longer an edge port
One that can be detected on a switch interface (ie. Up/down)
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers

34. What does Root Guard do?
Controls where candidate root bridges can be connected and found on a network
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.
Hashing algorithm
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

35. What is the default VTP state?
VTP server for domain null with no password or secure mode
By sending a gratuitous ARP
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
Real-time Transport Protocol

36. What is RTP?
Cisco ILP and 802.3af
Real-time Transport Protocol
On root - because the root bridge propagates timers with config BDPU
Group (0-1023) priority (1-255 higher better def 100)

37. What is arp throttling?
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
If a unidirectional link is detected - the switch doesn't try to reestablish the link. ULD msgs are sent once/sec for 8 seconds - then the port is err-disabled
Only a single host connects . If one BDPU is received - it is no longer an edge port
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region

38. What is UDLD normal mode?
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
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
They must be carried over a voice VLAN (VVID) or over a regular data VLAN (ie. The native VLAN or the PVID)
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated

39. What are the 6 steps to configure 802.1x for port security?
L2
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
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy
Port that connects to another switch and becomes a designated port

40. In a converged fabric - which switch(es) send config BDPUs?
Root
Incoming frames dropped - but MACs learned
Untrusted
The wireless clients communicate directly with no other means of connectivity such as a WAP

41. What is an insignificant topology change?
Data and voice over native vlan no QOS and no 802.1p trunk
Controls where candidate root bridges can be connected and found on a network
Value - mask - and result (VMR) combinations
A host port goes up or down

42. What is portfast?
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
With the skinny protocol
Effectively stops STP on filtered ports
Almost eliminates listening and learning states for single hosts on an access link

43. What does uplinkfast do?
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.
Because each frame is checked
Embeds the tag within the frame
Globally

44. What are the 2 power over ethernet methods?
Cisco ILP and 802.3af
Trusted or untrusted
Trunk
Manages addition - deletion and renaming VLANs across the network

45. RSTP backup port
Only the standby monitors the hello messages from the active router
Port stays up - packets from violating MACs dropped - no logging
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal

46. What is the size of a TCAM value?
1-1005 (1 and 1002-1005 are reserved)
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz
Immediate (class 2)
134 bits - consisting of source and destination addresses and protocol information from the packet or frame

47. How does loop guard block ports?
CEF is distributed completely among multiple L3 forwarding engines.
When a client roams between Aps in different subnets
Only for the offending VLAN on the port
Port

48. What is the acceptible range of VLANS?
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
1-1005 (1 and 1002-1005 are reserved)
Disabled - blocking - listening - learning - forwarding
Use sh interface on the interface and look for error counts > 10

49. What does the src-mac option do when checking ARP replies
Port stays up - packets from violating MACs dropped - no logging
Checks the source MAC in the header against the sender MAC in the ARP reply
The time that a port spends in both listening and learning states . Default 15 seconds
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified

50. What is the STP forwarding state?
Yes
Embeds the tag within the frame
300 sec
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs