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CCNP Switch Deck

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Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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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 the range of HSRP group numbers?
300 sec
Port
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
0-255

2. What is the STP forward delay timer?
If the switch or the powered device doesn't suport power class discovery
The time that a port spends in both listening and learning states . Default 15 seconds
A point to point port type
Immediate (class 2)

3. RSTP uses which standard?
When a port moves into forwarding or from fowarding or learning to blocking.
No shut
802.1w
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack

4. How does a DAI enabled switch gather trusted ARP info?
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
From the DHCP snooping database or from static entries
It is enabled by default on all CEF capable switches

5. How long are TCAM masks?
2 seconds (def)
134 bits
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
1 IP subnet

6. What is the traditional MLS view of switching?
Route once - switch many
Root
The configureable UDLD interval must be less than max age plus two intervals of forward delay
1 IP subnet

7. What contains the next-hop entries?
Used to switch packets destined for the null interface
FIB
An AP's coverage area
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan

8. What are the 2 UDLD modes?
Access
Connects with SONET or SDH
Group (0-1023) priority (1-255 higher better def 100)
Normal and aggressive

9. What is the STP blocking state?
Can hear only BDPUs
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.
By creating a static IP binding
By using an Ether-IP tunnel

10. What are 2 ways to configure VLAN and VTP information?
FIB
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
By creating a static IP binding

11. Which 4 things must be agreeable to trunk?
The total delay from start to finish
Port is forced to never authorize any connected client
Dynamic WEP keys that change periodically
1- trunking mode - 2-trunk encapsulation - 3-native VLAN - 4-allowed VLAN

12. What are the steps to configure a PAgP port channel?
Trunk
Group (0-1023) priority (1-255 higher better def 100)
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode
Connects with SONET or SDH

13. What is a baby giant frame?
Globally
Frames that barely exceed 1518B or 1622B due to headers
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports

14. How does RSTP converge?
If a proposal is received - the recipient isolates - all nonedge ports blocked until proposal sent causing neighbors to synch - which propagates out in waves
Root - designated - blocking - alternate - forwarding (host)
VTP server for domain null with no password or secure mode
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

15. What is RPR?
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
Enables portfast - sets the port to access and disables PAgP
0-255
The same as a standby group in HSRP

16. When should CDP be enabled?
Only for trusted Cisco gear - especially phones
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
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry

17. What is NSF?
Access or trunk
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.
When a client roams between Aps in different subnets
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover

18. How does PAgP form etherchannels?
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.

19. What do you need to determine to use MSTP?
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
Best effort delivery - integrated services model - and differentiated services model
No shut
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance

20. What are the 4 steps in DHCP negotiation?
By using an Ether-IP tunnel
Change in trunk encap
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack

21. What is layer 3 roaming?
When a client roams between Aps in different subnets
Yes
Trusted or untrusted
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port

22. if the switchport is part of an etherchannel - Where is the network assigned
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance
Discarding - learning - forwarding
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS
To the virtual port-channel interface

23. Where should you change the network diameter value?
Cisco recommends only on the root bridge
Distribution
Packets are discarded due to an ACL or policy action
Per VLAN

24. What is a wireless mobility group?
A client can roam to any WLC as long as it stays in a mobility group
Src-dst-ip
The total delay from start to finish
When the size of a cell is intentionally reduced

25. What is the default MTU?
300 sec by default
1500B
10-15%
The time that a port spends in both listening and learning states . Default 15 seconds

26. 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
Configure non-silent submode
Manually
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another

27. What 2 conditions does IP source guard check for?
Auto mode
802.1w
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry
The DCF interframe space- the random backoff time before a wireless set can transmit

28. What is a service set?
RPR - RPR+ - and SSO
A group of wireless devices that share a common SSID
Port stays up - packets from violating MACs dropped - no logging
CEF is distributed completely among multiple L3 forwarding engines.

29. Where is bdpu guard enabled?
Frames that barely exceed 1518B or 1622B due to headers
LWAPP (Cisco proprietary) and CAP-WAP (standards based)
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
All user ports that have portfast enabled

30. Where should STP timers be configured and why?
All ports where root isn't expected
Best effort delivery - integrated services model - and differentiated services model
Data goes over native vlan - voice goes over specified VLAN - voice QOS is 802.1p
On root - because the root bridge propagates timers with config BDPU

31. If a wireless station needs to transmit and another device is transmitting - what happens?
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority
The TOS field in the header is used. 2 methods 3 bits or 6 bits
1-1005 (1 and 1002-1005 are reserved)

32. When DHCP snooping is turned on - by default - it considers all ports ______
The wireless clients communicate directly with no other means of connectivity such as a WAP
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode
Untrusted
By using a hash of a key string

33. What are the restrictions for bundling into an Etherchannel?
Usually QoS from VOIP but not PC dataa
Configure non-silent submode
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
Must be same type - speed - VLAN(s) - native vlan - pass the same set of vlans -duplex - and spanning tree settings

34. How does packet forwarding work
26-byte header - 4-byte trailer with CRC
Arp for local subnet - if on different subnet - will arp for dgw
The frame tag contains a 3 but portion tagged from 0 (low) to 7 (high)
Access

35. What is a wall wart?
An ac adaptor that plugs into a wall outlet.
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.
Forces the router to wait for a period of time before attempting overthrow
Each frame transmits its expected duration time

36. How is UDLD configured?
To a VLAN and not to a VLAN interface (SVI)
By an ARP access list that defines the permitted bindings
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
When the AP uplinks to an Ethernet network.

37. Define HSRP
Using digital certificates
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry
Group (0-1023) priority (1-255 higher better def 100)

38. What is a vlan?
Port is forced to never authorize any connected client
Use the spanning-tree root macro
A single broadcast domain
Distribution layer

39. What is an autonomous mode AP?
When each AP stands alone within the larger network.
The distribution layer should have only L3 links
Trusted or untrusted
Trunk - dynamic auto - dynamic desireable (default)

40. What does MSTP do?
Used when there are 1 or more VLANs mapped to a single STP instance
Configure the timer on the AVG and let it propagate
1- enable qos - 2-define qos parameters to be trusted - 3-make trust conditional - 4-instruct IP phone how to extnd boundary
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added

41. What pins does FE use?
Data and voice over native vlan no QOS and no 802.1p trunk
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive
The same as a standby group in HSRP
1/2 and 3/6

42. How are VACLs applied
Incoming frames dropped - but MACs learned
To a VLAN and not to a VLAN interface (SVI)
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
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

43. What is DSCP codepoint EF(46)?
Interim solution - uses same hardware as WEP - but uses TKIP encryption
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
Critical...used most often for IPT
Isl - dot1q - negotiate (default)

44. What is portfast?
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
Embeds the tag within the frame
Almost eliminates listening and learning states for single hosts on an access link
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive

45. What is the default VTP state?
Silent
VTP server for domain null with no password or secure mode
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
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

46. What is an untrusted port under dhcp snooping?
Roughly 2000
When each AP stands alone within the larger network.
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
Enables portfast - sets the port to access and disables PAgP

47. What is RTP?
Flash (class 3)
A private VLAN can be logically associated with a special secondary vlan
Real-time Transport Protocol
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets

48. What are the port channel load balancing methods?
To a VLAN and not to a VLAN interface (SVI)
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified
Switching Database Manager - configures and prunes TCAM partitions

49. What are the 5 steps a LAP uses to establish communication with a WLC?
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
Incoming frames dropped - but MACs learned
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
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds

50. At what layer does EAPOL run?
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
Round robin - weighted - or host-dependent
L2