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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 are the PAgP negotiation modes
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
Priority (class 1)
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)

2. Which ports should you consider trusted for DAI?
Regions and instances
A MAC is seen on a different port
Those that connect to other switches
134 bits - consisting of source and destination addresses and protocol information from the packet or frame

3. How does backbonefast determine whether alternative paths exist?
The frame tag contains a 3 but portion tagged from 0 (low) to 7 (high)
The station can transmit immediately and wait for an ack
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
Matching SSID - compatible data rate - authentication credentials

4. How does the standby handle ARP issues after it becomes active?
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
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
300 sec

5. How do IP phones communicate with each other?
Both layer 2 switching and IVR
Once the CCM gives them the parameters - they use RTP
5 (0-4 with 4 being the highest)
Only for the offending VLAN on the port

6. What is the portr ID?
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
16 bits (8b port priority - 8b port number)
Data goes over native vlan - voice goes over specified VLAN - voice QOS is 802.1p
FE - GE - and aggregated FE/GE Etherchannels

7. What is the RSTP default hello interval?
2 seconds
Via an 802.1Q trunk or a single VLAN access port
For hosts that doesn't understand routing - the DGW is configured to reply with its own mac
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology

8. RSTP backup port
Used to switch packets destined for the null interface
Prevents the dhcp binding DB from being checked.
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
Incoming frames dropped - but MACs learned

9. What is a wireless mobility group?
A client can roam to any WLC as long as it stays in a mobility group
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
The number of times the entry has been updated since the table was generated
Between interfaces that are assigned to L2 VLANs or L2 trunks

10. What is portfast?
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
PAgP (Cisco proprietary) and LACP (standards-based)
When the AP uplinks to an Ethernet network.
Almost eliminates listening and learning states for single hosts on an access link

11. What is DCF?
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
Distributed coordinion function - the use of timers to prevent wireless collisions
Critical...used most often for IPT
One that can be detected on a switch interface (ie. Up/down)

12. What does the ip option do when checking ARP replies

13. WEP encryption
Weak key rotation
The station can transmit immediately and wait for an ack
12 kbps with headers and compression
CEF is distributed completely among multiple L3 forwarding engines.

14. Of what significance are private VLANs
Local only
300 sec by default
Another router must have a higher HSRP priority and have preemt set up
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN

15. How are BDPUs spread?
Multicast to 01-80-c2-00-00-00
Determines when the AVG will stop using the old VMAC in ARP replies
Once the CCM gives them the parameters - they use RTP
Because each frame is checked

16. Can two switches in the auto(PAgP) or passive (LACP) mode create a channel? Why?
1-LAP gets a DHCP address - 2-LAP learns IP of available WLC - 3-LAP sends a join request to WLC and receives join reply - 4-WLC sends code image - if necessary - 5-Tunnels are created
No because they only participate if asked
An L2 switch can only forward frames best effort unless going across a trunk
Reboots and searches for a new WLC

17. 802.11a
Globally
The switch checks the MAC and IP reported in the reply against trusted values. If they don't match - it is dropped and logged
Configure the timer on the AVG and let it propagate
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz

18. When DHCP snooping is turned on - by default - it considers all ports ______
Untrusted
A point to point port type
Used to switch packets destined for the null interface
SC fiber or RJ-45

19. What is an indirect topology change?
The link status stays up - but something between them has failed or is filtering traffic
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
When the AP uplinks to an Ethernet network.
Using a mobility exchange message

20. What is NSF?
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
FE - GE - and aggregated FE/GE Etherchannels
The link status stays up - but something between them has failed or is filtering traffic
Another router must have a higher HSRP priority and have preemt set up

21. What's the easiest way to configure GLBP timers?
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
Configure the timer on the AVG and let it propagate
Gateway load balancing protocol - cisco proprietary
The port asks the other end to trunk

22. How does ILP do power discovery?
1/2 and 3/6
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
Turn on port security

23. What are the three basic types of QOS?
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
Best effort delivery - integrated services model - and differentiated services model
The TOS field in the header is used. 2 methods 3 bits or 6 bits
Change in trunk encap

24. 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
Can send and receive BDPUs
Multicast to 01-80-c2-00-00-00
Virtual Router Redundancy Protocol - pretty much the same as HSRP

25. What is the default network diameter?
Using digital certificates
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
Port with best root path cost on segment
7 switches from root bridge

26. What are the 5 steps to manualy configure STP?
When a wireless station transmits a frame - the receiving one must send an ack
The ASIC
Virtual Router Redundancy Protocol - pretty much the same as HSRP
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

27. EAP encryption
Prevents the dhcp binding DB from being checked.
Differentiated services code point
No
Dynamic WEP keys that change periodically

28. What is UDLD aggressive mode?

29. What does Root Guard do?
Distribution layer
Controls where candidate root bridges can be connected and found on a network
Port is forced to never authorize any connected client
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan

30. What happens when an ARP reply is received on an untrusted port?

31. What is latency?
The total delay from start to finish
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology
Switches make an effort to move packets as quickly as possible
FE - GE - and aggregated FE/GE Etherchannels

32. How can you tell if a switch block is too large?
19
Routers at the distribution layer become the bottlenecks or broadcast or multicast traffic slows the switches in the switch block
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
By default weight is 100. Can be made dynamic per interface

33. How do VRRP routers handle preemption?
The number of times the CEF table has bee flushed and regenerated as a whole
On by default
PAgP (Cisco proprietary) and LACP (standards-based)
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS

34. How many potential links can LACP define?
Switches make an effort to move packets as quickly as possible
16 - of which up to 8 are active. The others are in standby
4
0-255 (lower is better)

35. What is the default FE duplex?
Full duplex
Virtual Router Redundancy Protocol - pretty much the same as HSRP
As a VLAN access map
Frames are forwarded

36. What is a discard adjacency?
Trusted ports
Packets are discarded due to an ACL or policy action
Real-time Transport Protocol
1- enable qos - 2-define qos parameters to be trusted - 3-make trust conditional - 4-instruct IP phone how to extnd boundary

37. What is a bridge ID made up of?
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
Bridge priority and MAC
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
Sends a voltage across the receive pairs to detect a 25k ohm resistance

38. How is a WLC handoff handled when the WLCs are in different subnets?
Based on priority (0-255). Default is 100. Highest IP is tie breaker
By using an Ether-IP tunnel
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
Globally

39. How does HSRP plain text authentication work?
Route once - switch many
A key string of up to 8 characters is sent. Default is cisco.
By using an Ether-IP tunnel
Trunk

40. How many users should be within a switch block?
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
Roughly 2000
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
That they aren't using the same frequencies.

41. What are the caveats for HSRP port tracking?
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset
Trunk - dynamic auto - dynamic desireable (default)
Another router must have a higher HSRP priority and have preemt set up
The campus network's backbone

42. what if a secondary VLAN?
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
By encapsulating each frame in a header and trailer
2-8 FE - GE - or 10GE are bundled.
FE and GE

43. How are GLBP timers used?
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec
1- trunking mode - 2-trunk encapsulation - 3-native VLAN - 4-allowed VLAN
Normal and aggressive

44. What is the access layer best practice?
Completed dhcp bindings - mac addresses - IP addresses - etc.
Switch(config-if)# standby xx where x= group number
All L2 connectivity should be contained within the access layer.
Real-time functions such as beacons and probes - encryption and interactions with the client at L2

45. What address does HSRP send hello packets to?
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
224.0.0.2 (all routers)
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
Silent

46. How do Cisco IP phones communicate with the CCM?
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
Globally
With the skinny protocol
Trusted ports

47. How are multiple VLANs mapped to multiple SSIDs?
By using a trunk link
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
Trunk - dynamic auto - dynamic desireable (default)

48. What is a cell?

49. What is step 1 of enabling IP source guard?
Configure and enable DHCP snooping
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
FE - GE - and aggregated FE/GE Etherchannels
Admin down

50. What is RPVST+?
No
Checks the source MAC in the header against the sender MAC in the ARP reply
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive
802.1x with EAP over LAN (EAPOL)