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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 often are BDPUs sent?
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
2 seconds (def)
0-255

2. What is the duration time in a wireless frame?
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
Each frame transmits its expected duration time
FIB
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

3. What is common spanning tree (CST)?
300 sec by default
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
Single instance of STP for all VLANs. BDPUs are sent over trunks using the native VLAN with untagged frames. Dot1q based
The number of times the entry has been updated since the table was generated

4. What feedback mechanism does wireless use?
Dynamic arp inspection
When a wireless station transmits a frame - the receiving one must send an ack
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry

5. What is the size of a TCAM value?
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
Cisco recommends only on the root bridge
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
Untrusted

6. What is layer 3 roaming?
The number of times the CEF table has bee flushed and regenerated as a whole
5 classes with 3 drop precedences
When a client roams between Aps in different subnets
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy

7. What does the rewrite engine do?
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
300 sec by default
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains

8. Define VRRP
Virtual Router Redundancy Protocol - pretty much the same as HSRP
2 seconds (def)
A VLAN that spans the entire fabric
Differentiated services

9. What is a direct topology change?
All nondesignated ports - but ok for all ports
The port asks the other end to trunk
Each frame transmits its expected duration time
One that can be detected on a switch interface (ie. Up/down)

10. What is the default MTU?
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
1500B
FE and GE
The number of times the entry has been updated since the table was generated

11. How many designated ports are there?
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
1 per segment

12. What is the traditional MLS view of switching?
Completed dhcp bindings - mac addresses - IP addresses - etc.
Route once - switch many
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
Yes

13. How does HSRP do MD5 authentication?
Isl - dot1q - negotiate (default)
By using a hash of a key string
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
Value - mask - and result (VMR) combinations

14. What is the VRRP skew time?
Determines when the AVG will stop using the old VMAC in ARP replies
Show standby
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added

15. What is the range of PAgP channel group numbers?
Yes
1 to 64
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
1/2 and 3/6

16. What can the Etherchannel hash use?
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
0-255
Cisco ILP and 802.3af
Between interfaces that are assigned to L2 VLANs or L2 trunks

17. What 2 conditions does IP source guard check for?
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
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry
1 second. Backup routers can learn the interval from the master
The frame tag contains a 3 but portion tagged from 0 (low) to 7 (high)

18. What is the 80/20 rule?
80% of the user traffic should stay in the VLAN
Using a mobility exchange message
Root - designated - alternate - and backup
802.1D

19. What does the version number indicate when looking at CEF entries?
An L2 switch can only forward frames best effort unless going across a trunk
No shut
By default weight is 100. Can be made dynamic per interface
The number of times the entry has been updated since the table was generated

20. What does Loop Guard do?
All ARP packets that arrive on untrusted ports are inspected.
Single instance of STP for all VLANs. BDPUs are sent over trunks using the native VLAN with untagged frames. Dot1q based
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
As a VLAN access map

21. What is the port number range?
3 seconds. Holdtime =3 hellos + 1
0-255
Roughly 2000
An AP's coverage area

22. What is the cost of a 100Mbps link?
19
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
FE and GE
Untrusted

23. What is integrated services model QOS?
Per VLAN
By brining up a tunnel between them to carry 802.11 related messages and client data.
Port with best root path cost on segment
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.

24. What is a null adjacency?
Used to switch packets destined for the null interface
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz
The wireless clients communicate directly with no other means of connectivity such as a WAP
Flash (class 3)

25. What is the portr ID?
Use sh interface on the interface and look for error counts > 10
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
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
16 bits (8b port priority - 8b port number)

26. How does dot1q do trunking?
Effectively stops STP on filtered ports
Dynamic arp inspection
Differentiated services
Embeds the tag within the frame

27. What is the default VTP state?
A point to point port type
Can hear only BDPUs
VTP server for domain null with no password or secure mode
Almost eliminates listening and learning states for single hosts on an access link

28. What are the 2 types of BDPU?
Configuration and TCN
The DCF interframe space- the random backoff time before a wireless set can transmit
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.
Effectively stops STP on filtered ports

29. What is a BSS?
Auto mode
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
Change in trunk encap
Using a single WAP to centralize access and control over a group of wireless devices.

30. What is PVST plus (PVST+)?
10-15%
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
A host port goes up or down
A client can roam to any WLC as long as it stays in a mobility group

31. RSTP point to point port
Edge - root - and point to point
Yes
Port that connects to another switch and becomes a designated port
10-15%

32. What is the port priority range?
0000.5e00.01xx
0-255 (lower is better)
The wireless clients communicate directly with no other means of connectivity such as a WAP
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS

33. What is the STP blocking state?
5 classes with 3 drop precedences
By short-circuiting the max age timer
When a specific interface is tracked - HSRP reduces it's priority after a specified interval.
Can hear only BDPUs

34. What is portfast?
The port is forced to always authorize any connected client with no authentication necessary (default)
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
Almost eliminates listening and learning states for single hosts on an access link
The station can transmit immediately and wait for an ack

35. How should backbonefast be configured?
On all switches in network to enable RLQ request and reply
1 IP subnet
To a VLAN and not to a VLAN interface (SVI)
900 MHz - 2.4Ghz - and 5-6GHz

36. What is 802.1x force-unauthorized?
Can hear only BDPUs
Port is forced to never authorize any connected client
Edge - root - and point to point
Show standby

37. What is the distribution layer best practice?
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
From the DHCP snooping database or from static entries
Dynamic WEP keys that change periodically
The distribution layer should have only L3 links

38. What types of link can an etherchannel be?
Access or trunk
Configure the timer on the AVG and let it propagate
Untrusted
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority

39. What is BDPU Guard?
Every switch and router in a network must be configured with appropriate QoS features and policies
If any BDUP is received on a port - it puts the port into the errdisable state
802.1x with EAP over LAN (EAPOL)
When the AP uplinks to an Ethernet network.

40. How are BDPUs spread?
Multicast to 01-80-c2-00-00-00
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz
Root
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

41. What is jitter?
Switch(config-if)# vrrp xx where xx= group number
802.11
Globally
Variation in delay

42. What is an end to end vlan?
A VLAN that spans the entire fabric
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
When a specific interface is tracked - HSRP reduces it's priority after a specified interval.
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan

43. What is the core block?

44. What happens when switches receive a configuration BDPU?
Distributed coordinion function - the use of timers to prevent wireless collisions
Checks the source MAC in the header against the sender MAC in the ARP reply
By an ARP access list that defines the permitted bindings
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)

45. How does 802.1q handle COS?
After forwarding delay - port can learn new MAC addresses
Yes
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client

46. What are the 5 STP port roles?
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance
An ac adaptor that plugs into a wall outlet.
Root - designated - blocking - alternate - forwarding (host)
1 IP subnet

47. Where should you change the network diameter value?
Cisco recommends only on the root bridge
Matching SSID - compatible data rate - authentication credentials
Prevents the dhcp binding DB from being checked.
0-255 (lower is better)

48. How does an LAP bind with a WLC?
By brining up a tunnel between them to carry 802.11 related messages and client data.
Port with best root path cost
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN

49. Can MSTP interoperate with 802.1q and/or PVST+?
Yes to both
A group of wireless devices that share a common SSID
By using an Ether-IP tunnel
The time that a port spends in both listening and learning states . Default 15 seconds

50. What if RSTP BDPUs aren't received?
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.
Manages addition - deletion and renaming VLANs across the network
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
Full duplex