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 is the adjacency table?
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
Within a single MST region - an IST instances runs to work out a loop free topology between links where CST meets the region boundary and all switches in the region. It runs at the boundary.
300 sec
When the AP uplinks to an Ethernet network.


2. What does the SP do?
All ports where root isn't expected
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
SC fiber or RJ-45
Incoming frames dropped - but MACs learned


3. What are the PAgP negotiation modes
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
All ports where root isn't expected
1-1005 (1 and 1002-1005 are reserved)
An instance of RSTP running for each VLAN on the switch. Changing from PVST to RPVST+ is disruptive


4. RSTP root port
10-15%
Port with best root path cost
Full duplex
All fiber-optic links between switches (must be enabled on both ends)


5. What is an autonomous mode AP?
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
Global config (vlan - vtp mode - and vtp domain) and VLAN DB mode commands. Global config is preferred because VLAN DB mode commands are legacy
Will trunk if asked
When each AP stands alone within the larger network.


6. What does Root Guard do?
Controls where candidate root bridges can be connected and found on a network
Prevents the dhcp binding DB from being checked.
Checks the source MAC in the header against the sender MAC in the ARP reply
Checks the sender's ip in all arp requests and checks the sender's IP against target IP in all replies


7. the static port to vlan membership is handled in _____
Untrusted
The ASIC
Protects STP when a physical malfunction only allows traffic in 1 direction - even though the link shows as up (cisco proprietary)
Globally


8. How does RSTP converge?
All user ports that have portfast enabled
If a proposal is received - the recipient isolates - all nonedge ports blocked until proposal sent causing neighbors to synch - which propagates out in waves
Packets must be sent to the L3 engine for further processing
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port


9. What is SSO?

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10. What routing protocols support NSF?
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
BGP - EIGRP - OSPF - and IS-IS.
Packets must be sent to the L3 engine for further processing
Plain text or md5


11. How are RSTP point to point ports determined?
Yes
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
Automatically by duplex mode in use. Full duplex are point ot point. Half duplex ports use traditional 802.1D convergence is used.
One that can be detected on a switch interface (ie. Up/down)


12. What are the caveats for HSRP port tracking?
Roughly 2000
Another router must have a higher HSRP priority and have preemt set up
BGP - EIGRP - OSPF - and IS-IS.
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


13. How does the CEF L3 engine operate?

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14. What are dynamic VLANs based on?
Port with redundant - but less deisrable connection to a segment. Possibly root candidate
Configure non-silent submode
MAC of the end device
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another


15. What are spoofed addresses?
LACP port priority
Checks the destination MAC in the header against the target MAC in the ARP reply
They disguise the origin of an attack
1 to 64


16. What are the steps to configure MST?
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
Transmits keystrokes from phone and commands from CCM
Using digital certificates
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


17. What criteria are used to size a switch block?
That they aren't using the same frequencies.
By name - config revision - and instance to vlan mapping table
If the switch or the powered device doesn't suport power class discovery
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains


18. What is the STP listening state?
Every switch and router in a network must be configured with appropriate QoS features and policies
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
Can send and receive BDPUs
The time that a port spends in both listening and learning states . Default 15 seconds


19. What is a community secondary VLAN?
By an ARP access list that defines the permitted bindings
Hosts within a secondary can communicate with each other and with the primary - but not with another secondary vlan
Each frame transmits its expected duration time
Regions and instances


20. On what scope is DAI enabled?
Per VLAN
When a port moves into forwarding or from fowarding or learning to blocking.
Used when there are 1 or more VLANs mapped to a single STP instance
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


21. How is an RSTP edge port configured
Create 2 hsrp groups - each with the active router being different switches - then have clients point to each
With portfast
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
When the size of a cell is intentionally reduced


22. What is an untrusted port under dhcp snooping?
Gateway load balancing protocol - cisco proprietary
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
2 seconds (def)
Port stays up - packets from violating MACs dropped - no logging


23. How do you show HSRP status
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
2
Show standby
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz


24. What functions does a LAP perform?
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
Turn on port security
Only for the offending VLAN on the port
Usually QoS from VOIP but not PC dataa


25. can root guard and udld be used together?
Interim solution - uses same hardware as WEP - but uses TKIP encryption
Yes
Checks the destination MAC in the header against the target MAC in the ARP reply
Half-duplex


26. How long are TCAM masks?
Dynamic arp inspection
After forwarding delay - port can learn new MAC addresses
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry
134 bits


27. What are the 2 types of BDPU?
Configuration and TCN
Packets must be sent to the L3 engine for further processing
Use the spanning-tree root macro
The TOS field in the header is used. 2 methods 3 bits or 6 bits


28. What happens when the topology changes?

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29. What are the 4 steps to extend QoS trust?
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
1- enable qos - 2-define qos parameters to be trusted - 3-make trust conditional - 4-instruct IP phone how to extnd boundary
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


30. What is the acceptible range of VLANS?
FE and GE
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
Either desirable or auto mode
1-1005 (1 and 1002-1005 are reserved)


31. What is the VRRP skew time?
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry
By short-circuiting the max age timer
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
A MAC is seen on a different port


32. What are the steps to configure a PAgP port channel?
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode
It is enabled by default on all CEF capable switches
Hashing algorithm
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client


33. What must you be sure of if AP cells overlap?

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34. What is the bridge priority range?
The switch checks the MAC and IP reported in the reply against trusted values. If they don't match - it is dropped and logged
0-65535 (def 32768) lower=better
Per VLAN
Virtual Router Redundancy Protocol - pretty much the same as HSRP


35. What is step 1 of enabling IP source guard?
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
A point to point port type
The same as a standby group in HSRP
Configure and enable DHCP snooping


36. RSTP uses which standard?
Up to 4 can be used in a group. Called active virtual forwarders (AVF)
For hosts that doesn't understand routing - the DGW is configured to reply with its own mac
802.1w
SC fiber or RJ-45


37. What are TCAM entries composed of?
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
Set the native VLAN of a trunk to a bogus or unused VLAN ID then prune the native VLAN off both ends of the trunk
Value - mask - and result (VMR) combinations
Tracks of BDPUs on nondesignated ports. When those BDPUs stop coming - the port is put into loop-inconsistent state and blocks


38. What is a CEF glean?

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39. What types of ports autonegotiate?
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p
2-8 FE - GE - or 10GE are bundled.
FE and GE
Disabled - blocking - listening - learning - forwarding


40. Does VTP pass private VLAN configuration?
SC fiber or RJ-45
No
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
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


41. RSTP designated port
L2
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
Port with best root path cost on segment
Cisco ILP and 802.3af


42. How much BW does a PSTN connection use?
63 kbps
0007.b4xx.xxyy where xx.xx is six 0 bits followed by a 10-bit GLBP group numberr. Yyyy is the virtual forwarder number
Automatically using DTP and CDP
Round robin - weighted - or host-dependent


43. What is unique about HSRP group numbers?
The switch checks the MAC and IP reported in the reply against trusted values. If they don't match - it is dropped and logged
Full duplex
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable


44. What is the 80/20 rule?
Half because transmitting and receiving stations use the same frequency
80% of the user traffic should stay in the VLAN
224.0.0.2 (all routers)
Edge - root - and point to point


45. What is the range of PAgP channel group numbers?
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
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
1 to 64
0000.5e00.01xx


46. What address does HSRP send hello packets to?
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover
2-8 FE - GE - or 10GE are bundled.
224.0.0.2 (all routers)
It is enabled by default on all CEF capable switches


47. What are the characteristics of the core layer
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
224.0.0.2 (all routers)
Switchpotrt nonegotiate
The standby becomes active and stays active by default. Preemption can be configured


48. What are the 6 HSRP states?
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
By creating a static IP binding
By using a hash of a key string
Disabled - init - listen - speak - standby - active


49. If there are 2 ports with same root cost - how is the tie broken for designated port?
Disabled - blocking - listening - learning - forwarding
The ASIC
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
Enables portfast - sets the port to access and disables PAgP


50. What is a vlan?
Trusted or untrusted
A single broadcast domain
Receives the first packet of a traffic flow and routes it
Virtual Router Redundancy Protocol - pretty much the same as HSRP