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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 3 RSTP port types?
It can't
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
Edge - root - and point to point
The configureable UDLD interval must be less than max age plus two intervals of forward delay

2. How does GLBP work?
Collision domain
Routers are assigned to common GLBP group. All routers can be active and can load balance
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
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure

3. What is RPR+?

4. Where should STP timers be configured and why?
By using a trunk link
5 classes with 3 drop precedences
On root - because the root bridge propagates timers with config BDPU
After forwarding delay - port can learn new MAC addresses

5. Automatically configure STP timers
Use the spanning-tree root macro
By using a hash of a key string
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
On all switches in network to enable RLQ request and reply

6. What is the port priority range?
0-255 (lower is better)
2 - one for control messages and one for data
Root - designated - alternate - and backup
Best effort delivery - integrated services model - and differentiated services model

7. How does an LAP bind with a WLC?
Control functions
By brining up a tunnel between them to carry 802.11 related messages and client data.
RPR - RPR+ - and SSO
FIB

8. What pins does FE use?
That they aren't using the same frequencies.
1/2 and 3/6
1500B
No

9. What is the port number range?
0-255
Root - designated - blocking - alternate - forwarding (host)
Disabled - init - listen - speak - standby - active
Lowest cumulative cost to root

10. What is accelerated CEF (aCEF)?
Flash override (class 4)
Flash (class 3)
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
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset

11. What is the STP forward delay timer?
MST attributes must be manually entereed on each switch in the region. They don' t propagate like VTP.
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
The time that a port spends in both listening and learning states . Default 15 seconds
Once the CCM gives them the parameters - they use RTP

12. What is the STP blocking state?
Can hear only BDPUs
After another forwarding delay - the port can send and receive data frames - collect MAC addresses - and send and receove BDPUs
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
TCAM

13. How can BDPU Guard be configured?
Hosts within a secondary can communicate with each other and with the primary - but not with another secondary vlan
Data and voice over native vlan no QOS and no 802.1p trunk
Globally or per-port
The frame tag includes a 3 bit COS value from 0 (low) to 7 (high). Native vlans are untagged so no COS

14. How many 802.3af power classes are there?
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
A path is pre-arranged for priority along the complete path from source to destination using the RSVP protocol.
5 (0-4 with 4 being the highest)
Via an 802.1Q trunk or a single VLAN access port

15. What are dynamic VLANs based on?
Both ends should be on because on modes doesn't send PAgP or LACP packets
PAgP (Cisco proprietary) and LACP (standards-based)
L2
MAC of the end device

16. What duplex setting does 802.11 use and why?
If any BDUP is received on a port - it puts the port into the errdisable state
An L2 switch can only forward frames best effort unless going across a trunk
300 sec by default
Half because transmitting and receiving stations use the same frequency

17. What is a discard adjacency?
Plain text or md5
Etherchannel ports have inconsistent config
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
Packets are discarded due to an ACL or policy action

18. What is the portr ID?
16 bits (8b port priority - 8b port number)
Trunk
Yes
Yes

19. How does a WLC hand off a client's association to another WLC?
Any ports associated with an isolated vlan can reach the primary - but not any other secondary. Hosts withn an isolated vlan can't reach each other
Virtual Router Redundancy Protocol - pretty much the same as HSRP
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
Using a mobility exchange message

20. What is portfast?
The wireless clients communicate directly with no other means of connectivity such as a WAP
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
Almost eliminates listening and learning states for single hosts on an access link
26-byte header - 4-byte trailer with CRC

21. 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.
When each AP stands alone within the larger network.
Needs hardware upgrade over WEP - uses AES encryption
Up to 4 can be used in a group. Called active virtual forwarders (AVF)

22. What is 802.1x force-unauthorized?
Port is forced to never authorize any connected client
The switch adds its MAC to the option 82 field so that the DHCP reply echoes back the switch's own information
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
Configure non-silent submode

23. Whan is a 10GE WAN PHY?
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
Connects with SONET or SDH
Regions and instances
0-65535 (def 32768) lower=better

24. What is PVST plus (PVST+)?
Allows devices to interoperate with PVST and CST. Can use both dot1q and ISL
1 -2 -5.5 and 11 Mbps - Channels 1/6/11 - 2.4Ghz
A point to point port type
An ac adaptor that plugs into a wall outlet.

25. What is the FM?
Needs hardware upgrade over WEP - uses AES encryption
If the client maintains the same IP address as it roams between Aps. All must have same VLAN - SSID - and subnet
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
10-15%

26. What does the rewrite engine do?
63 kbps
Interim solution - uses same hardware as WEP - but uses TKIP encryption
If a proposal is received - the recipient isolates - all nonedge ports blocked until proposal sent causing neighbors to synch - which propagates out in waves
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information

27. RSTP BPDU structure
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
Automatically using DTP and CDP
Only when a nonedge port transitions to forwarding
Trunk

28. can root guard and bdpu guard be used together?
Dynamic WEP keys that change periodically
Edge - root - and point to point
No
Matching SSID - compatible data rate - authentication credentials

29. How often are CAM table entries aged?
FE and GE
Both ends should be on because on modes doesn't send PAgP or LACP packets
Trusted or untrusted
300 sec

30. What is BDPU Guard?
5 classes with 3 drop precedences
802.1x with EAP over LAN (EAPOL)
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
If any BDUP is received on a port - it puts the port into the errdisable state

31. How does the VRRP master router handle the VIP?
300 sec by default
By default weight is 100. Can be made dynamic per interface
Automatically negotiates a common trunk mode between switches
The master router can share the VIP

32. What are the gotchas for uplinkfast?

33. What is the PVLAN host mode?
1/2 and 3/6
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan
They should be an unconditional Etherchannel because the WLC can't negotiate a channel.
RADIUS

34. How does ILP do power discovery?
Configure the timer on the AVG and let it propagate
Sends a test tone on the transmit pair. If a device is detected - CDP is used to narrow down the power class.
On all switches in network to enable RLQ request and reply
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.

35. How should UDLD be configured?
The configureable UDLD interval must be less than max age plus two intervals of forward delay
Effectively stops STP on filtered ports
The DCF interframe space- the random backoff time before a wireless set can transmit
Untrusted

36. What is backbonefast?
Protects STP when a physical malfunction only allows traffic in 1 direction - even though the link shows as up (cisco proprietary)
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
Variation in delay
Distributed coordinion function - the use of timers to prevent wireless collisions

37. How are multiple VLANs mapped to multiple SSIDs?
By using a trunk link
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
When the size of a cell is intentionally reduced
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports

38. How should backbonefast be configured?
On (all ports channel) - auto (channels when asked) - and desirable(actively asks to form a channel)
Source IP - dest IP - combination of source and dest IP - source and dest MAC - or TCP/UDP port numbers
By configuring every switch port to have an expected and controlled behavior
On all switches in network to enable RLQ request and reply

39. How is Root Guard used?
Switches make an effort to move packets as quickly as possible
Automatically using DTP and CDP
On ports where you never expect to find a root bridge for a VLAN
A single broadcast domain

40. Where is root guard enabled?

41. By default - what submode does PAgP operate in with the desirable and auto modes?
0-65535 (def 32768) lower=better
Using a single WAP to centralize access and control over a group of wireless devices.
Silent
Show standby

42. How much overlap should WAPs have?
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p
Checks the sender's ip in all arp requests and checks the sender's IP against target IP in all replies
10-15%
Differentiated services code point

43. How are frames forwarded across a specific link?
Hashing algorithm
Etherchannel ports have inconsistent config
Roughly 50%
The number of times the CEF table has bee flushed and regenerated as a whole

44. How is a WLC handoff handled when the WLCs are in different subnets?
All user ports that have portfast enabled
16 bits (8b port priority - 8b port number)
By using an Ether-IP tunnel
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

45. static vlans offer ____ based membership
By encapsulating each frame in a header and trailer
Port
Cisco proprietary. 1 instance of STP/VLAN. Requires ISL instead of dot1q
Trunk

46. What 2 tunnelling mechanisms do the LAP and WLC use to communicate?
Port that connects to another switch and becomes a designated port
LWAPP (Cisco proprietary) and CAP-WAP (standards based)
When the AP uplinks to an Ethernet network.
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information

47. How are VACLs applied
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
By short-circuiting the max age timer
26-byte header - 4-byte trailer with CRC
To a VLAN and not to a VLAN interface (SVI)

48. What are the 5 steps to manualy configure STP?
Connects to a router - firewall - or gateway. Can communicate with anything else connected to the primary or any secondary. Ignores pvlan config
FIB
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
Isl - dot1q - negotiate (default)

49. What is the default 802.3af power class and its use?

50. How does HSRP gateway addressing work
16 bits (8b port priority - 8b port number)
Matching SSID - compatible data rate - authentication credentials
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
The number of times the entry has been updated since the table was generated