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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 is BDPU Guard?
Port with best root path cost on segment
If any BDUP is received on a port - it puts the port into the errdisable state
Only for the offending VLAN on the port
All user ports that have portfast enabled

2. What is a root link query (RLQ)?
Virtual Router Redundancy Protocol - pretty much the same as HSRP
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover

3. What are the RSTP port roles?
Root - designated - alternate - and backup
Access
The master router can share the VIP
63 kbps

4. What is a direct topology change?
One that can be detected on a switch interface (ie. Up/down)
Critical...used most often for IPT
The standby becomes active and stays active by default. Preemption can be configured
Yes to both

5. How does a DHCP server send WLC addresses?
All L2 connectivity should be contained within the access layer.
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
Option 43
The link status stays up - but something between them has failed or is filtering traffic

6. What is a VRRP group?
By using an Ether-IP tunnel
SC fiber or RJ-45
134 bits
The same as a standby group in HSRP

7. How does the CEF L3 engine operate?

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8. Whan is a 10GE WAN PHY?
Connects with SONET or SDH
Another router must have a higher HSRP priority and have preemt set up
Real-time Transport Protocol
The station can transmit immediately and wait for an ack

9. What are the 3 RSTP port types?
The number of times the CEF table has bee flushed and regenerated as a whole
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port
Round robin - weighted - or host-dependent
Edge - root - and point to point

10. How are RSTP point to point ports determined?
Dynamic arp inspection
134 bits - consisting of source and destination addresses and protocol information from the packet or frame
802.1w
Automatically by duplex mode in use. Full duplex are point ot point. Half duplex ports use traditional 802.1D convergence is used.

11. What is the access layer best practice?
All L2 connectivity should be contained within the access layer.
Usually QoS from VOIP but not PC dataa
Admin down
From the DHCP snooping database or from static entries

12. Can loop guard and udld be used together?
Yes
Route processor redundancy - redundant sup is partially booted and initialized and must reload module in the switch and init all sup functions
Makes use of the DHCP snooping database and static ip source binding entries. If enabled - switch will test addresses
5 (0-4 with 4 being the highest)

13. What is a drop adjacency?

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14. What is layer 3 roaming?
When a client roams between Aps in different subnets
If any BDUP is received on a port - it puts the port into the errdisable state
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
Up to 4 can be used in a group. Called active virtual forwarders (AVF)

15. How does Root Guard work?

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16. How does HSRP do MD5 authentication?
By using a hash of a key string
It's a router that maintains routes (static or dynamic) - and populates the FIB
No shut
Priority (class 1)

17. WPA encryption
Interim solution - uses same hardware as WEP - but uses TKIP encryption
Disabled - init - listen - speak - standby - active
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.
Usually QoS from VOIP but not PC dataa

18. What does BDPU filtering do?
Effectively stops STP on filtered ports
Globally
Show standby
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs

19. How do you implement MST?

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20. How many links can be used in an EtherChannel?
Priority (class 1)
Between interfaces that are assigned to L2 VLANs or L2 trunks
Port with best root path cost
2-8 FE - GE - or 10GE are bundled.

21. What is an MST instance?
The MST instance (MSTI) runs alongside the IST and represents an STP instance
Edge - root - and point to point
Using a single WAP to centralize access and control over a group of wireless devices.
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links

22. What happens when switches receive a configuration BDPU?
Hosts associated with a secondary VLAN can communicate with ports on the primary but not with another secondary VLAN
When the AP uplinks to an Ethernet network.
An AP's coverage area
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)

23. What does the SP do?
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
Value - mask - and result (VMR) combinations
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
BGP - EIGRP - OSPF - and IS-IS.

24. What is 802.1x auto?
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server
The port uses 802.1x exchange to move from unauthorized to authorized. Requires app on client
The number of times the CEF table has bee flushed and regenerated as a whole
Checks the source MAC in the header against the sender MAC in the ARP reply

25. can root guard and bdpu guard be used together?
Turn on port security
No
Manually
FIB

26. What does the switchport host macro do?
The wireless clients communicate directly with no other means of connectivity such as a WAP
A private VLAN can be logically associated with a special secondary vlan
Between interfaces that are assigned to L2 VLANs or L2 trunks
Sets the switchport mode to access - enables portfast - and turns off channel grouping for the port

27. What is 802.1x force-unauthorized?
No
Port is forced to never authorize any connected client
Normal and aggressive
Both ends should be on because on modes doesn't send PAgP or LACP packets

28. What is UDLD normal mode?
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated
Low cost - high density ports - multiple scalable uplinks - vlans - traffic and protocol filtering and QoS
Group (0-255) - priority (1-254 254 is highest - 100 default)
When each AP stands alone within the larger network.

29. What are the 3 ways GLBP load-balances?
Round robin - weighted - or host-dependent
Embeds the tag within the frame
All nondesignated ports - but ok for all ports
Switchpotrt nonegotiate

30. What is DSCP codepoint AF41(34)?
Flash override (class 4)
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
Use the spanning-tree root macro

31. 802.11g
Between any type of interface as long as the interface can have an L3 address assigned
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
Arp for local subnet - if on different subnet - will arp for dgw
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz

32. What is an ESS?
When the AP uplinks to an Ethernet network.
All nondesignated ports - but ok for all ports
The topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding
1-(opt) configure load balancing - 2-select the interface(s) - 3-assign the protocol - 4-select the mode and submode

33. How is an RSTP edge port configured
4
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
With portfast
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.

34. RSTP learning state
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
Incoming frames dropped - but MACs learned
The ASIC
Two distribution switches that aggregate one or more access switches

35. Where shoul dmultilayer switches be implemented?
Distribution layer
Cisco recommends only on the root bridge
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
Yes

36. What is the adjacency table?
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
Protects STP when a physical malfunction only allows traffic in 1 direction - even though the link shows as up (cisco proprietary)
Differentiated services
Prevents the dhcp binding DB from being checked.

37. What does the RP do?
Receives the first packet of a traffic flow and routes it
A key string of up to 8 characters is sent. Default is cisco.
A private VLAN can be logically associated with a special secondary vlan
Limits the number if dhcp requests on a port

38. What is backbonefast?
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack
Switching Database Manager - configures and prunes TCAM partitions
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
63 kbps

39. How much overlap should a wireless repeater have?
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
Roughly 50%
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
Used to switch packets destined for the null interface

40. What is the portr ID?
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
16 bits (8b port priority - 8b port number)
Isl - dot1q - negotiate (default)
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string

41. What does MSTP consist of?
Connects to a host on an isolated or community vlan. Communicates only with promiscuous port or ports on same community vlan
Regions and instances
Connects to a router - firewall - or gateway. Can communicate with anything else connected to the primary or any secondary. Ignores pvlan config
By configuring every switch port to have an expected and controlled behavior

42. 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
0007.b4xx.xxyy where xx.xx is six 0 bits followed by a 10-bit GLBP group numberr. Yyyy is the virtual forwarder number
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.
L2

43. How does a Cisco IP phone connect upstream?
After forwarding delay - port can learn new MAC addresses
Automatically using DTP and CDP
Via an 802.1Q trunk or a single VLAN access port
A VLAN that spans the entire fabric

44. What is the range of HSRP group numbers?
0-255
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
Change in trunk encap

45. What is a service set?
0000.5e00.01xx
The TOS field in the header is used. 2 methods 3 bits or 6 bits
A group of wireless devices that share a common SSID
Per VLAN

46. 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)
BGP - EIGRP - OSPF - and IS-IS.
By using a hash of a key string
Port

47. How does HSRP election work?
Based on priority (0-255). Default is 100. Highest IP is tie breaker
16 - of which up to 8 are active. The others are in standby
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p
2 seconds

48. Where is bdpu guard enabled?
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another
All user ports that have portfast enabled
Switch(config-if)# vrrp xx where xx= group number
The standby becomes active and stays active by default. Preemption can be configured

49. How should the switch port to which an autonomous AP be configured?
Trunk
Limits the number if dhcp requests on a port
Configure non-silent submode
Control functions

50. What does the dst-mac option do when checking ARP replies
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
All nondesignated ports - but ok for all ports
Effectively stops STP on filtered ports
Checks the destination MAC in the header against the target MAC in the ARP reply