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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. How does DSCP handle IP precedence?
5 classes with 3 drop precedences
Best effort delivery - integrated services model - and differentiated services model
That they aren't using the same frequencies.
0-65535 (def 32768) lower=better

2. Where are security and QoS ACLs stored?
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
16 - of which up to 8 are active. The others are in standby
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
TCAM

3. What is the format of the VRRP virtual MAC?
Switches make an effort to move packets as quickly as possible
0000.5e00.01xx
The number of times the entry has been updated since the table was generated
Can send and receive BDPUs

4. What is a null adjacency?
Group (0-1023) priority (1-255 higher better def 100)
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
As a VLAN access map
Used to switch packets destined for the null interface

5. What is the adjacency table?
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology
On root - because the root bridge propagates timers with config BDPU
For hosts that doesn't understand routing - the DGW is configured to reply with its own mac
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry

6. How does adding option-82 to DHCP snooping affect things?

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7. How do you configure DAI for statically configured IP addresses?
On by default
By an ARP access list that defines the permitted bindings
Edge - root - and point to point
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.

8. How are multiple VLANs mapped to multiple SSIDs?
Port is forced to never authorize any connected client
By using a trunk link
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
Another router must have a higher HSRP priority and have preemt set up

9. Define VRRP
Virtual Router Redundancy Protocol - pretty much the same as HSRP
2
No
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port

10. How do you disable DTP when you configure both ends of the ISL manually?
Disabled - blocking - listening - learning - forwarding
Switchpotrt nonegotiate
Configure and enable DHCP snooping
A point to point port type

11. How should the switch port to which a WLC be configured?
Trunk
The configureable UDLD interval must be less than max age plus two intervals of forward delay
Stateful switchover - redundant sup is fully booted and init'd. Both start and run config are synched as is L2 information - and switchinterfaces.
Group (0-255) - priority (1-254 254 is highest - 100 default)

12. What does the src-mac option do when checking ARP replies
Collision domain
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
Root - designated - blocking - alternate - forwarding (host)
Checks the source MAC in the header against the sender MAC in the ARP reply

13. What is SSO?

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14. Where should STP timers be configured and why?
Can hear only BDPUs
On root - because the root bridge propagates timers with config BDPU
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
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz

15. What are dynamic VLANs based on?
2 seconds
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
Local only
MAC of the end device

16. What happens if both 802.1D and RSTP BDPUs are received?
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
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
Root - designated - alternate - and backup
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD

17. At what layer does EAPOL run?
Automatically using DTP and CDP
Dynamic arp inspection
L2
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge

18. What does VTP do?
By using a hash of a key string
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
Manages addition - deletion and renaming VLANs across the network
Configure non-silent submode

19. RSTP forwarding state
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
Frames are forwarded
Only for trusted Cisco gear - especially phones

20. What is DSCP codepoint EF(46)?
Critical...used most often for IPT
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string
By creating a static IP binding
63 kbps

21. How does HSRP plain text authentication work?
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.
Sends a voltage across the receive pairs to detect a 25k ohm resistance
A key string of up to 8 characters is sent. Default is cisco.
The MST instance (MSTI) runs alongside the IST and represents an STP instance

22. How do you renable an err-disable port by default?
With the skinny protocol
1 IP subnet
Manually
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan

23. Each switch port is a _____ ______
Disabled - blocking - listening - learning - forwarding
Priority (class 1)
Half because transmitting and receiving stations use the same frequency
Collision domain

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

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25. What are the two etherchannel negotiation protocols?
No
Matching SSID - compatible data rate - authentication credentials
PAgP (Cisco proprietary) and LACP (standards-based)
Full duplex

26. How does an L2 switch do QOS?
0-255
An L2 switch can only forward frames best effort unless going across a trunk
Almost eliminates listening and learning states for single hosts on an access link
Effectively stops STP on filtered ports

27. Where is the QoS trust boundary usually configured on an IP phone?
Usually QoS from VOIP but not PC dataa
FE - GE - and aggregated FE/GE Etherchannels
By encapsulating each frame in a header and trailer
26-byte header - 4-byte trailer with CRC

28. Can MSTP interoperate with 802.1q and/or PVST+?
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
Yes to both
A single broadcast domain
When the size of a cell is intentionally reduced

29. What criteria are used to size a switch block?
Either desirable or auto mode
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains
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
Change in trunk encap

30. What functions does a WLC perform?
To the virtual port-channel interface
Control functions
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
900 MHz - 2.4Ghz - and 5-6GHz

31. What are the 6 steps to configure 802.1x for port security?
Yes
1-1005 (1 and 1002-1005 are reserved)
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
Limits the number if dhcp requests on a port

32. What pins does FE use?
Globally or per-port
1/2 and 3/6
0000.5e00.01xx
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information

33. How does ISL do trunking?
On all switches in network to enable RLQ request and reply
By encapsulating each frame in a header and trailer
Flash (class 3)
Trunk - dynamic auto - dynamic desireable (default)

34. How are RSTP point to point ports determined?
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
A packet can't be switched in hardware with the FIB and must go to the L3 engine
Automatically by duplex mode in use. Full duplex are point ot point. Half duplex ports use traditional 802.1D convergence is used.
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string

35. How are GLBP timers used?
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec
Arp for local subnet - if on different subnet - will arp for dgw
802.11
A port can only forward or relay BDPUs - but can't receive them - disabled by default - enabled per-port - blocks port when superior BDPUs are received

36. How does every VRRP command begin?
Frames that barely exceed 1518B or 1622B due to headers
Isl - dot1q - negotiate (default)
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified
Switch(config-if)# vrrp xx where xx= group number

37. What are the 3 RSTP port types?
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
Edge - root - and point to point
L2
2

38. What is step 1 of enabling IP source guard?
Configure and enable DHCP snooping
No
0000.5e00.01xx
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry

39. What is GLBP weight?
By default weight is 100. Can be made dynamic per interface
They disguise the origin of an attack
1 IP subnet
Half because transmitting and receiving stations use the same frequency

40. What is the distribution layer best practice?
Distributed coordinion function - the use of timers to prevent wireless collisions
Trunk
The distribution layer should have only L3 links
Edge - root - and point to point

41. By default - what layer do catalyst switchports operate on?
L2
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz
An ac adaptor that plugs into a wall outlet.
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting

42. What does DTP do?
Automatically negotiates a common trunk mode between switches
Flash override (class 4)
Effectively stops STP on filtered ports
0-65535 (def 32768) lower=better

43. What is dhcp snooping rate limiting?
A VLAN that spans the entire fabric
On ports where you never expect to find a root bridge for a VLAN
Limits the number if dhcp requests on a port
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers

44. What duplex setting does 802.11 use and why?
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
Half because transmitting and receiving stations use the same frequency
Checks the source MAC in the header against the sender MAC in the ARP reply
By encapsulating each frame in a header and trailer

45. What is the access layer best practice?
Critical...used most often for IPT
All L2 connectivity should be contained within the access layer.
Via an 802.1Q trunk or a single VLAN access port
Group (0-255) - priority (1-254 254 is highest - 100 default)

46. What format does the GLBP MAC use?
Differentiated services
Once the CCM gives them the parameters - they use RTP
0007.b4xx.xxyy where xx.xx is six 0 bits followed by a 10-bit GLBP group numberr. Yyyy is the virtual forwarder number
1 to 64

47. What is the SDM?
Switching Database Manager - configures and prunes TCAM partitions
A VLAN that spans the entire fabric
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
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

48. How does backbonefast determine whether alternative paths exist?
Manually
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
Turn on port security
26-byte header - 4-byte trailer with CRC

49. What is the VRRP master router?
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
The active router. All other routers are in backup state
The configureable UDLD interval must be less than max age plus two intervals of forward delay
By short-circuiting the max age timer

50. What is the core block?

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