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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 DSCP codepoint AF11(10)?
900 MHz - 2.4Ghz - and 5-6GHz
On root - because the root bridge propagates timers with config BDPU
Priority (class 1)
PAgP (Cisco proprietary) and LACP (standards-based)

2. What is the default MTU?
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
1500B
Distributed coordinion function - the use of timers to prevent wireless collisions
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS

3. How many MST instances can be in a region?
Flash override (class 4)
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
Yes
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region

4. What are spoofed addresses?
By using a trunk link
They disguise the origin of an attack
The master router can share the VIP
An ac adaptor that plugs into a wall outlet.

5. What are the 2 types of secondary VLAN?
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
Port with best root path cost on segment
FIB
Isolated and community

6. What is the VRRP skew time?
On by default
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
0-255

7. What is the STP Max Age timer?
FE and GE
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
Globally
Root - designated - alternate - and backup

8. What is the standard for WLANs?
The wireless clients communicate directly with no other means of connectivity such as a WAP
1 to 64
802.11
Cisco ILP and 802.3af

9. How do you configure a DHCP gateway?
By default weight is 100. Can be made dynamic per interface
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Access or trunk

10. What does the dst-mac option do when checking ARP replies
Checks the destination MAC in the header against the target MAC in the ARP reply
By sending a gratuitous ARP
300 sec
For hosts that doesn't understand routing - the DGW is configured to reply with its own mac

11. CAM table entries are purged when....
80% of the user traffic should stay in the VLAN
The ASIC
A MAC is seen on a different port
By using a trunk link

12. Where is UDLD enabled?
Use sh interface on the interface and look for error counts > 10
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.
0007.b4xx.xxyy where xx.xx is six 0 bits followed by a 10-bit GLBP group numberr. Yyyy is the virtual forwarder number
All fiber-optic links between switches (must be enabled on both ends)

13. What is the size of a TCAM value?
Completed dhcp bindings - mac addresses - IP addresses - etc.
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
If a proposal is received - the recipient isolates - all nonedge ports blocked until proposal sent causing neighbors to synch - which propagates out in waves
Multicast to 01-80-c2-00-00-00

14. What is an indirect topology change?
The link status stays up - but something between them has failed or is filtering traffic
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
Automatically using DTP and CDP
A point to point port type but the neighboring device runs traditional 802.1D STP

15. What is the cost of a 1Gbps link?
Trusted or untrusted
The TOS field in the header is used. 2 methods 3 bits or 6 bits
4
Group (0-1023) priority (1-255 higher better def 100)

16. RSTP edge port
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz
Only a single host connects . If one BDPU is received - it is no longer an edge port
L2
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID

17. What is an autonomous mode AP?
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
1-65535 (def 32768) lower priority - higher probability
Local only
When each AP stands alone within the larger network.

18. What can cause a wireless client to switch between Aps?
Port
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry
Missed beacons - dropped packets (max retry) - weak signal (data rate switches down) - an AP periodicallytries to find a stronger signal
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

19. What is 802.1x force-authorized?
The port is forced to always authorize any connected client with no authentication necessary (default)
It is enabled by default on all CEF capable switches
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.
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

20. If a wireless station needs to transmit and no other device is transmitting - what happens?
A MAC is seen on a different port
Roughly 50%
The station can transmit immediately and wait for an ack
By brining up a tunnel between them to carry 802.11 related messages and client data.

21. What cabling do GBICs use?
Only a single host connects . If one BDPU is received - it is no longer an edge port
SC fiber or RJ-45
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance

22. What is an ESS?
When the AP uplinks to an Ethernet network.
0000.0c07.acxx where xx is the group number as a 2-digit hex value
Both ends should be on because on modes doesn't send PAgP or LACP packets
By brining up a tunnel between them to carry 802.11 related messages and client data.

23. How are VACLs applied
To a VLAN and not to a VLAN interface (SVI)
The active router. All other routers are in backup state
By an ARP access list that defines the permitted bindings
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks

24. What is an IST instance?
Frames that barely exceed 1518B or 1622B due to headers
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.
Differentiated services code point
Once the CCM gives them the parameters - they use RTP

25. How many 802.3af power classes are there?
5 (0-4 with 4 being the highest)
Determines when the AVG will stop using the old VMAC in ARP replies
That they aren't using the same frequencies.
Etherchannel ports have inconsistent config

26. What is integrated services model QOS?
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
A point to point port type but the neighboring device runs traditional 802.1D STP
Limits the number if dhcp requests on a port
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.

27. What is the STP learning state?
After forwarding delay - port can learn new MAC addresses
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
No
Real-time Transport Protocol

28. Where does layer switching occur?
Port with best root path cost on segment
When a port moves into forwarding or from fowarding or learning to blocking.
Between any type of interface as long as the interface can have an L3 address assigned
Flash (class 3)

29. What is a topology change?
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
Regions and instances
Two distribution switches that aggregate one or more access switches
When a port moves into forwarding or from fowarding or learning to blocking.

30. How is a WLC handoff handled when the WLCs are in different subnets?
By using an Ether-IP tunnel
Prevents the dhcp binding DB from being checked.
No
After forwarding delay - port can learn new MAC addresses

31. What is the size of ISL encapsulation?
Two distribution switches that aggregate one or more access switches
26-byte header - 4-byte trailer with CRC
Group (0-255) - priority (1-254 254 is highest - 100 default)
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.

32. What does port-security protect do?
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
Manually
Port stays up - packets from violating MACs dropped - no logging
19

33. How does ILP do power discovery?
If any BDUP is received on a port - it puts the port into the errdisable state
A client can roam to any WLC as long as it stays in a mobility group
The port will operate under 802.1D rules. If they are received on the same port - it will run 802.1D until the migration delay expires
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.

34. Does GLBP allow preemption?
Between interfaces that are assigned to L2 VLANs or L2 trunks
On all switches in network to enable RLQ request and reply
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
Yes

35. 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
0-255
Weak key rotation
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology

36. How many designated ports are there?
Used when ACLs specify port ranges...used by TCAM
1 per segment
By using an Ether-IP tunnel
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs

37. What is a null adjacency?
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
Used to switch packets destined for the null interface
Trunk

38. What 2 tunnelling mechanisms do the LAP and WLC use to communicate?
To a VLAN and not to a VLAN interface (SVI)
PAgP (Cisco proprietary) and LACP (standards-based)
Distribution layer
LWAPP (Cisco proprietary) and CAP-WAP (standards based)

39. What does the switchport host macro do?
LACP port priority
Enables portfast - sets the port to access and disables PAgP
On the left as you face the connector
0-255 (lower is better)

40. What are the PAgP negotiation modes
Port is forced to never authorize any connected client
No
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs

41. What does the standby HSRP router do?
Only the standby monitors the hello messages from the active router
Those that connect to other switches
300 sec
Automatically using DTP and CDP

42. Does a WLC and a LAP need to be on the same subnet?
Distribution layer
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 frame transmits its expected duration time
No

43. What must you be sure of if AP cells overlap?

44. What if RSTP BDPUs aren't received?
0-255 (lower is better)
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.

45. How do you disable DTP when you configure both ends of the ISL manually?
Distribution layer
Because each frame is checked
Switchpotrt nonegotiate
Packets must be sent to the L3 engine for further processing

46. What are the 3 RSTP port types?
Edge - root - and point to point
They disguise the origin of an attack
Manually
1 second. Backup routers can learn the interval from the master

47. What does the skinny protocol do?
Transmits keystrokes from phone and commands from CCM
Using digital certificates
Root - designated - blocking - alternate - forwarding (host)
It's a router that maintains routes (static or dynamic) - and populates the FIB

48. What is latency?
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
The total delay from start to finish
Manually
Because each frame is checked

49. 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
TCAM
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance
12 kbps with headers and compression

50. What are the VRRP group and priority numbers?
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
Group (0-255) - priority (1-254 254 is highest - 100 default)
Normal and aggressive