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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 does UDLD work?
Automatically negotiates a common trunk mode between switches
Change in trunk encap
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
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

2. How do you configure IP source guard for hosts that don't use DHCP?
Prevents the dhcp binding DB from being checked.
They must be carried over a voice VLAN (VVID) or over a regular data VLAN (ie. The native VLAN or the PVID)
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another
By creating a static IP binding

3. What are the 2 UDLD modes?
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
By default weight is 100. Can be made dynamic per interface
Normal and aggressive
12 kbps with headers and compression

4. How does dot1q do trunking?
Embeds the tag within the frame
16 - of which up to 8 are active. The others are in standby
Either desirable or auto mode
Based on priority (0-255). Default is 100. Highest IP is tie breaker

5. What is the GLBP AVG?
Multicast to 01-80-c2-00-00-00
Dynamic arp inspection
One router is the active virtual gateway - has highest priority or IP in group - answers all ARP requests and gives MAC based on load balancing
Can send and receive BDPUs

6. What format does the GLBP MAC use?
An AP's coverage area
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
Data and voice over native vlan no QOS and no 802.1p trunk
0007.b4xx.xxyy where xx.xx is six 0 bits followed by a 10-bit GLBP group numberr. Yyyy is the virtual forwarder number

7. How does IPT behave when the voice VLAN is in untagged mode?
0007.b4xx.xxyy where xx.xx is six 0 bits followed by a 10-bit GLBP group numberr. Yyyy is the virtual forwarder number
Needs hardware upgrade over WEP - uses AES encryption
MST attributes must be manually entereed on each switch in the region. They don' t propagate like VTP.
Data and voice over native vlan - no QOS but still uses 802.1p trunk

8. What are the steps of RSTP convergence?
Can hear only BDPUs
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
With portfast
Promiscuous and host

9. What is PVST plus (PVST+)?
Switching Database Manager - configures and prunes TCAM partitions
Real-time Transport Protocol
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
300 sec by default

10. How does a WLC hand off a client's association to another WLC?
0-65535 (def 32768) lower=better
Receives the first packet of a traffic flow and routes it
No
Using a mobility exchange message

11. What is a QoS trust boundary?
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
Flash (class 3)
Checks the destination MAC in the header against the target MAC in the ARP reply
No

12. How long are TCAM masks?
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
When each AP stands alone within the larger network.
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
134 bits

13. What are the characteristics of the distribution layer?
Automatically using DTP and CDP
Trusted or untrusted
1 to 64
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links

14. What is a PVLAN?
Completed dhcp bindings - mac addresses - IP addresses - etc.
Roughly 2000
One router is the active virtual gateway - has highest priority or IP in group - answers all ARP requests and gives MAC based on load balancing
A private VLAN can be logically associated with a special secondary vlan

15. What is best effort delivery QOS?
It can't
Switches make an effort to move packets as quickly as possible
The time that a port spends in both listening and learning states . Default 15 seconds
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. What is DCF?
1 second. Backup routers can learn the interval from the master
Connects with SONET or SDH
Distributed coordinion function - the use of timers to prevent wireless collisions
The campus network's backbone

17. What are dynamic VLANs based on?
Manages addition - deletion and renaming VLANs across the network
1 second. Backup routers can learn the interval from the master
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
MAC of the end device

18. RSTP root port
Port with best root path cost
Receives the first packet of a traffic flow and routes it
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance
The number of times the CEF table has bee flushed and regenerated as a whole

19. Can two switches in the auto(PAgP) or passive (LACP) mode create a channel? Why?
Embeds the tag within the frame
Receives the first packet of a traffic flow and routes it
A single broadcast domain
No because they only participate if asked

20. What are the 5 steps to manualy configure STP?
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
10-15%
Regions and instances
Weak key rotation

21. Can MSTP interoperate with 802.1q and/or PVST+?
The configureable UDLD interval must be less than max age plus two intervals of forward delay
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
Yes to both
Only a single host connects . If one BDPU is received - it is no longer an edge port

22. What is the STP forward delay timer?
MAC of the end device
Root
The time that a port spends in both listening and learning states . Default 15 seconds
FE - GE - and aggregated FE/GE Etherchannels

23. what should you do if you expect a PAgP capable switch at the other end vs. a server or host?
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive
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
Local only
Configure non-silent submode

24. What is the bridge priority range?
Collision domain
0-65535 (def 32768) lower=better
16 - of which up to 8 are active. The others are in standby
Every switch and router in a network must be configured with appropriate QoS features and policies

25. How does GLBP work?
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
Routers are assigned to common GLBP group. All routers can be active and can load balance
When each AP stands alone within the larger network.
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec

26. can root guard and bdpu guard be used together?
Matching SSID - compatible data rate - authentication credentials
No
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks

27. Define VRRP
0-65535 (def 32768) lower=better
2 strand MMF with MT-RJ or SC connectors
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
Virtual Router Redundancy Protocol - pretty much the same as HSRP

28. How is Root Guard used?
16 bits (8b port priority - 8b port number)
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz
On ports where you never expect to find a root bridge for a VLAN

29. What is the VRRP skew time?
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
Change in trunk encap
Lowest cumulative cost to root
Flash (class 3)

30. What is an insignificant topology change?
The redundant SUP is booted and sup and route engine is init'd. No L2 or L3 functions are started. Allows switchports to retain state
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
900 MHz - 2.4Ghz - and 5-6GHz
A host port goes up or down

31. What does IP source guard do?
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
Gets assistance from other NSF-aware neighbors. NSF features need to be built into the routing protocols on router needing and providing assistance
Isolated and community
Switch(config-if)# glbp xx where xx = group number

32. What is a CEF punt?

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33. What is topology-basec caching?
Dynamic WEP keys that change periodically
The topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding
For hosts that doesn't understand routing - the DGW is configured to reply with its own mac
They disguise the origin of an attack

34. What are the steps to configuring HSRP MD5 authentication?
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string
Used when ACLs specify port ranges...used by TCAM
10-15%
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

35. What contains the next-hop entries?
802.1D
FIB
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP

36. What is the default mode of load balancing?
If three are missed in a row - the neighbor is considered down and the data for that neighbor is aged
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
Src-dst-ip
Two distribution switches that aggregate one or more access switches

37. What is the size of a TCAM value?
Plain text or md5
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
802.1D
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology

38. How does loop guard block ports?
MAC of the end device
Only for the offending VLAN on the port
Only for trusted Cisco gear - especially phones
By name - config revision - and instance to vlan mapping table

39. What is a baby giant frame?
Frames that barely exceed 1518B or 1622B due to headers
Plain text or md5
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
Embeds the tag within the frame

40. What is dynamic desireable?
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
1 second. Backup routers can learn the interval from the master
Limits the number if dhcp requests on a port
The port asks the other end to trunk

41. How can you tell if a switch block is too large?
Collision domain
Routers at the distribution layer become the bottlenecks or broadcast or multicast traffic slows the switches in the switch block
Via an 802.1Q trunk or a single VLAN access port
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.

42. What is the IEEE standard for STP?
802.1D
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
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.
PAgP (Cisco proprietary) and LACP (standards-based)

43. What is SSO?

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44. What are the two private vlan association modes?
By an ARP access list that defines the permitted bindings
Promiscuous and host
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
Single instance of STP for all VLANs. BDPUs are sent over trunks using the native VLAN with untagged frames. Dot1q based

45. What is the FM?
MAC of the end device
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
Option 43
Multicast to 01-80-c2-00-00-00

46. How much BW does a voip connection use?
The port is forced to always authorize any connected client with no authentication necessary (default)
12 kbps with headers and compression
802.11
Data and voice over native vlan no QOS and no 802.1p trunk

47. RSTP discarding state
0000.5e00.01xx
L2
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified
Incoming frames are dropped (combination of disabled - blocking - and listening)

48. How doed backbonefast work?
By short-circuiting the max age timer
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
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
A private VLAN can be logically associated with a special secondary vlan

49. What is the duration time in a wireless frame?
The MST instance (MSTI) runs alongside the IST and represents an STP instance
Each frame transmits its expected duration time
1- enable qos - 2-define qos parameters to be trusted - 3-make trust conditional - 4-instruct IP phone how to extnd boundary
Immediate (class 2)

50. When are RSTP bdpus sent?
0000.0c07.acxx where xx is the group number as a 2-digit hex value
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology
Matching SSID - compatible data rate - authentication credentials
No because they only participate if asked