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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. What are the port channel load balancing methods?
1-65535 (def 32768) lower priority - higher probability
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
Src-ip - dst-ip - src-dst-ip - src-mac - dst-mac - src-dst-mac - src-port - dst-port - src-dst-port
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP

2. How many tunnels exist between the LAP and WLC?
2 - one for control messages and one for data
Between interfaces that are assigned to L2 VLANs or L2 trunks
Roughly 50%
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

3. What is the STP forwarding state?
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
An ac adaptor that plugs into a wall outlet.
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen
Manages addition - deletion and renaming VLANs across the network

4. What is DSCP codepoint AF41(34)?
Roughly 50%
2-8 FE - GE - or 10GE are bundled.
Flash override (class 4)
7 switches from root bridge

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

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6. What is DSCP codepoint AF31(26)?
By creating a static IP binding
Connects to a router - firewall - or gateway. Can communicate with anything else connected to the primary or any secondary. Ignores pvlan config
Flash (class 3)
Single instance of STP for all VLANs. BDPUs are sent over trunks using the native VLAN with untagged frames. Dot1q based

7. Define VRRP
By name - config revision - and instance to vlan mapping table
Virtual Router Redundancy Protocol - pretty much the same as HSRP
L2
1 second. Backup routers can learn the interval from the master

8. What are the characteristics of the access layer?
3 seconds. Holdtime =3 hellos + 1
Weak key rotation
A group of wireless devices that share a common SSID
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS

9. Where are security and QoS ACLs stored?
With portfast
TCAM
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover

10. What are the 5 STP port roles?
A host port goes up or down
802.11
Each frame transmits its expected duration time
Root - designated - blocking - alternate - forwarding (host)

11. what if a secondary VLAN?
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
0-255
5 (0-4 with 4 being the highest)
Variation in delay

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

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13. What is the switch block?
A VLAN that spans the entire fabric
By short-circuiting the max age timer
Two distribution switches that aggregate one or more access switches
0-255

14. What is the acceptible range of VLANS?
26-byte header - 4-byte trailer with CRC
Only when a nonedge port transitions to forwarding
1-1005 (1 and 1002-1005 are reserved)
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table

15. What are the 2 types of BDPU?
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
Configuration and TCN
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance
Variation in delay

16. What does the rewrite engine do?
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
Hashing algorithm
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
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

17. What are the 5 STP states?
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
Group (0-255) - priority (1-254 254 is highest - 100 default)
Disabled - blocking - listening - learning - forwarding
Distribution layer

18. if the switchport is part of an etherchannel - Where is the network assigned
To the virtual port-channel interface
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
Hashing algorithm
Auto mode

19. What is layer 3 roaming?
L2
When a client roams between Aps in different subnets
Auto mode
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen

20. What is a QoS trust boundary?
2 seconds
0000.5e00.01xx
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS

21. How does an L2 switch do QOS?
Auto mode
By brining up a tunnel between them to carry 802.11 related messages and client data.
An L2 switch can only forward frames best effort unless going across a trunk
Variation in delay

22. What must be in common for a BSS to form?
Matching SSID - compatible data rate - authentication credentials
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
4
A private VLAN can be logically associated with a special secondary vlan

23. What is the cost of a 100Mbps link?
19
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
Real-time Transport Protocol
The configureable UDLD interval must be less than max age plus two intervals of forward delay

24. What is DSCP codepoint AF21(18)?
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
All fiber-optic links between switches (must be enabled on both ends)
1-lowest root bridge ID - 2-lowest root path cost - 3-lowest bridgeID - 4-lowest port ID
Immediate (class 2)

25. How does ILP do power discovery?
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
Port that connects to another switch and becomes a designated port
2-8 FE - GE - or 10GE are bundled.
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.

26. 802.11a
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz
Yes
Only for the offending VLAN on the port
The DCF interframe space- the random backoff time before a wireless set can transmit

27. What is the STP listening state?
Time between BDPUs sent by root bridge. Default of 2 seconds
CEF is distributed completely among multiple L3 forwarding engines.
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
Can send and receive BDPUs

28. What is an indirect topology change?
All L2 connectivity should be contained within the access layer.
Cisco ILP and 802.3af
PAgP (Cisco proprietary) and LACP (standards-based)
The link status stays up - but something between them has failed or is filtering traffic

29. Define HSRP
Port with best root path cost
Forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
Host Standby Router protocol. Cisco proprietary. Switch is either active - standby - or listen

30. What is the default 10mbps Enet duplex?
Half-duplex
After forwarding delay - port can learn new MAC addresses
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
Isolated and community

31. How does HSRP plain text authentication work?
Needs hardware upgrade over WEP - uses AES encryption
A key string of up to 8 characters is sent. Default is cisco.
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains
The DCF interframe space- the random backoff time before a wireless set can transmit

32. How does a Cisco IP phone connect upstream?
Via an 802.1Q trunk or a single VLAN access port
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.
5 classes with 3 drop precedences
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL

33. How does HSRP election work?
16 bits (8b port priority - 8b port number)
Based on priority (0-255). Default is 100. Highest IP is tie breaker
By default weight is 100. Can be made dynamic per interface
Discarding - learning - forwarding

34. How should backbonefast be configured?
Port that connects to another switch and becomes a designated port
On all switches in network to enable RLQ request and reply
Because each frame is checked
Use sh interface on the interface and look for error counts > 10

35. How does HSRP port tracking work?

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36. RSTP BPDU structure
All L2 connectivity should be contained within the access layer.
Yes
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
Real-time functions such as beacons and probes - encryption and interactions with the client at L2

37. What duplex setting does 802.11 use and why?
On by default
Another router must have a higher HSRP priority and have preemt set up
Half because transmitting and receiving stations use the same frequency
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan

38. What is a drop adjacency?

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39. On what scope is DAI enabled?
FE - GE - and aggregated FE/GE Etherchannels
Per VLAN
Trunk
16 - of which up to 8 are active. The others are in standby

40. What is integrated services model QOS?
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
Because each frame is checked
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.
The standby becomes active and stays active by default. Preemption can be configured

41. 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
Lowest cumulative cost to root
1 to 64
From the DHCP snooping database or from static entries

42. What is an untrusted port under dhcp snooping?
Needs hardware upgrade over WEP - uses AES encryption
All nondesignated ports - but ok for all ports
Both layer 2 switching and IVR
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable

43. What is an IST instance?
Limits the number if dhcp requests on a port
Configure the timer on the AVG and let it propagate
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.
2-8 FE - GE - or 10GE are bundled.

44. What is RPR?
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
To a VLAN and not to a VLAN interface (SVI)
The number of times the entry has been updated since the table was generated

45. How are GLBP timers used?
Packets are discarded due to an ACL or policy action
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated
Each peer sends and receives hellos. Def hello is 3 sec - def hold is 10 sec
Trusted or untrusted

46. What do you need to determine to use MSTP?
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
On by default
If any BDUP is received on a port - it puts the port into the errdisable state
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance

47. What is differentiated services model QOS?
L2
Each network device handles packets individually with no advance reservations
Discarding - learning - forwarding
The DCF interframe space- the random backoff time before a wireless set can transmit

48. What contains the next-hop entries?
Needs hardware upgrade over WEP - uses AES encryption
FIB
On root - because the root bridge propagates timers with config BDPU
Frames are forwarded

49. How does DSCP handle IP precedence?
Silent
5 classes with 3 drop precedences
Immediate (class 2)
802.1x with EAP over LAN (EAPOL)

50. How does every GLBP command begin
When the AP uplinks to an Ethernet network.
7 switches from root bridge
Switch(config-if)# glbp xx where xx = group number
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p