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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 does UDLD do?
Protects STP when a physical malfunction only allows traffic in 1 direction - even though the link shows as up (cisco proprietary)
When the size of a cell is intentionally reduced
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
Value - mask - and result (VMR) combinations

2. How is an instance defined?
Connects to a router - firewall - or gateway. Can communicate with anything else connected to the primary or any secondary. Ignores pvlan config
One that can be detected on a switch interface (ie. Up/down)
By name - config revision - and instance to vlan mapping table
When the AP uplinks to an Ethernet network.

3. What is an end to end vlan?
A VLAN that spans the entire fabric
Gateway load balancing protocol - cisco proprietary
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.
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information

4. What is the standard for WLANs?
Used when ACLs specify port ranges...used by TCAM
802.11
No
Yes

5. Where shoul dmultilayer switches be implemented?
Distribution layer
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
A packet can't be switched in hardware with the FIB and must go to the L3 engine

6. What is the bridge priority range?
Almost eliminates listening and learning states for single hosts on an access link
0-65535 (def 32768) lower=better
Immediate (class 2)
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

7. RSTP point to point port
Between interfaces that are assigned to L2 VLANs or L2 trunks
Port that connects to another switch and becomes a designated port
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.
2 - one for control messages and one for data

8. What are the 3 RSTP port types?
Edge - root - and point to point
16 - of which up to 8 are active. The others are in standby
Incoming frames are dropped (combination of disabled - blocking - and listening)
Only for the offending VLAN on the port

9. What happens when switches receive a configuration BDPU?
A point to point port type but the neighboring device runs traditional 802.1D STP
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
Port that connects to another switch and becomes a designated port
Half because transmitting and receiving stations use the same frequency

10. What are the 3 trunk encap modes?
Isl - dot1q - negotiate (default)
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Root
Another router must have a higher HSRP priority and have preemt set up

11. Can loop guard and udld be used together?
A single broadcast domain
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
One that can be detected on a switch interface (ie. Up/down)

12. RSTP discarding state
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
1500B
The configureable UDLD interval must be less than max age plus two intervals of forward delay
Incoming frames are dropped (combination of disabled - blocking - and listening)

13. What contains the next-hop entries?
FIB
Time between BDPUs sent by root bridge. Default of 2 seconds
A private VLAN can be logically associated with a special secondary vlan
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port

14. What is the range of HSRP group numbers?
An ac adaptor that plugs into a wall outlet.
0-255
Half because transmitting and receiving stations use the same frequency
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz

15. How does a DAI enabled switch gather trusted ARP info?
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
1500B
From the DHCP snooping database or from static entries
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets

16. What are the 3 trunk switchport modes?
On root - because the root bridge propagates timers with config BDPU
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
The frame tag contains a 3 but portion tagged from 0 (low) to 7 (high)
Trunk - dynamic auto - dynamic desireable (default)

17. What method of QOS does voice traffic use most frequently?
0-255 (lower is better)
Checks the destination MAC in the header against the target MAC in the ARP reply
Differentiated services
Configuration and TCN

18. What criteria are used to size a switch block?
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains
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.
RPR - RPR+ - and SSO
A MAC is seen on a different port

19. can root guard and loop guard be used together
No
300 sec by default
Yes
Option 43

20. What are the RSTP port states?
Discarding - learning - forwarding
Packets are discarded due to an ACL or policy action
Trunk
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

21. How do you prevent switch spoofing?
Priority (class 1)
The link status stays up - but something between them has failed or is filtering traffic
By configuring every switch port to have an expected and controlled behavior
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated

22. What are spoofed addresses?
Each frame transmits its expected duration time
They disguise the origin of an attack
Variation in delay
134 bits

23. How does UDLD work?
If any BDUP is received on a port - it puts the port into the errdisable state
On ports where you never expect to find a root bridge for a VLAN
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region

24. By default - what layer do catalyst switchports operate on?
802.11
1 second. Backup routers can learn the interval from the master
802.1w
L2

25. 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
With the skinny protocol
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
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.

26. What is the RSTP default hello interval?
2 seconds
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
2 seconds (def)

27. Where is bdpu guard enabled?
All user ports that have portfast enabled
Yes
Src-dst-ip
Yes

28. What are the PAgP negotiation modes
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
Auto mode
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
On by default

29. What is route caching?

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30. RSTP backup port
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
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
Turn on port security
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

31. How does HSRP gateway addressing work
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks
The number of times the entry has been updated since the table was generated
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added

32. How does DSCP handle IP precedence?
Etherchannel ports have inconsistent config
Switching Database Manager - configures and prunes TCAM partitions
5 classes with 3 drop precedences
Each network device handles packets individually with no advance reservations

33. What are the 4 steps to extend QoS trust?
5 (0-4 with 4 being the highest)
Only for the offending VLAN on the port
1- enable qos - 2-define qos parameters to be trusted - 3-make trust conditional - 4-instruct IP phone how to extnd boundary
Matching SSID - compatible data rate - authentication credentials

34. What is an MST instance?
The MST instance (MSTI) runs alongside the IST and represents an STP instance
Yes
Port with alternative path to root less desirable than root
Data and voice over native vlan - no QOS but still uses 802.1p trunk

35. What is a bridge ID made up of?
All ARP packets that arrive on untrusted ports are inspected.
Bridge priority and MAC
Stateful switchover - redundant sup is fully booted and init'd. Both start and run config are synched as is L2 information - and switchinterfaces.
Untrusted

36. How are VACLs configured?
As a VLAN access map
7 switches from root bridge
The switch checks the MAC and IP reported in the reply against trusted values. If they don't match - it is dropped and logged
Yes

37. How is root port decided upon?
16 bits (8b port priority - 8b port number)
Lowest cumulative cost to root
Automatically negotiates a common trunk mode between switches
Data goes over native vlan - voice goes over specified VLAN - voice QOS is 802.1p

38. What happens when the topology changes?

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39. What pins does FE use?
1/2 and 3/6
Auto mode
Can send and receive BDPUs
Only the standby monitors the hello messages from the active router

40. How do IP phones communicate with each other?
The distribution layer should have only L3 links
Manually
Once the CCM gives them the parameters - they use RTP
By using a trunk link

41. What are the 2 UDLD modes?
Normal and aggressive
1 second. Backup routers can learn the interval from the master
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
Only when a nonedge port transitions to forwarding

42. Whan is a 10GE WAN PHY?
1/2 and 3/6
12 kbps with headers and compression
Connects with SONET or SDH
Must be same type - speed - VLAN(s) - native vlan - pass the same set of vlans -duplex - and spanning tree settings

43. RSTP alternate port
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
Port with alternative path to root less desirable than root
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
That they aren't using the same frequencies.

44. How is RSTP synchronization accomplished?
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
Roughly 2000
Hashing algorithm
Use the spanning-tree root macro

45. What is a microcell?
Normal and aggressive
Enables portfast - sets the port to access and disables PAgP
When the size of a cell is intentionally reduced
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added

46. What is dhcp snooping rate limiting?
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
Limits the number if dhcp requests on a port
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
Promiscuous and host

47. What is dynamic desireable?
Distribution layer
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
The port asks the other end to trunk
Connects with SONET or SDH

48. How often are BDPUs sent?
2 seconds (def)
With portfast
Usually QoS from VOIP but not PC dataa
By sending a gratuitous ARP

49. Each switch port is a _____ ______
3 seconds. Holdtime =3 hellos + 1
The number of times the entry has been updated since the table was generated
Using a single WAP to centralize access and control over a group of wireless devices.
Collision domain

50. What is the GLBP AVG?
Prevents the dhcp binding DB from being checked.
Either desirable or auto mode
Listens to the first packet going to router and away from the router. If it can switch in both directions - it learns a shortcut path so subsequent packets can be switched without the RP
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