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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 the 80/20 rule?
They disguise the origin of an attack
A MAC is seen on a different port
80% of the user traffic should stay in the VLAN
Switchpotrt nonegotiate

2. How are BDPUs spread?
RADIUS
Receives the first packet of a traffic flow and routes it
Multicast to 01-80-c2-00-00-00
Data goes over native vlan - voice goes over VLAN0 - voice QOS is 802.1p

3. What does the version number indicate when looking at CEF entries?
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Group (0-255) - priority (1-254 254 is highest - 100 default)
The number of times the entry has been updated since the table was generated
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.

4. When looking at the sh spanning tree output - What does P2P denote?
A point to point port type
26-byte header - 4-byte trailer with CRC
L2
1-name the chain - 2-establish a key number - 3-create the key string - 4-apply the chain to the string

5. RSTP designated port
Port with best root path cost on segment
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs
Turn on port security
Every hello interval regardless of whether BDPUs are received from root - allowing any switch to take an active role maintaining the topology

6. How do you find duplex mismatches?
Cisco recommends only on the root bridge
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
Use sh interface on the interface and look for error counts > 10
Lowest cumulative cost to root

7. How does a WLC hand off a client's association to another WLC?
Differentiated services code point
Using a mobility exchange message
Either desirable or auto mode
Variation in delay

8. How should the switch port to which a WLC be configured?
802.1x with EAP over LAN (EAPOL)
Trunk
802.1D
Frames that barely exceed 1518B or 1622B due to headers

9. What does Root Guard do?
Controls where candidate root bridges can be connected and found on a network
Because each frame is checked
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
All ARP packets that arrive on untrusted ports are inspected.

10. What is the default mode of load balancing?
Src-dst-ip
Regions and instances
Option 43
Nonstop forwarding is an interactive method focusing on rebuilding the RIB after SUP switchover

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

12. Where is bdpu guard enabled?
All user ports that have portfast enabled
Configure non-silent submode
Interim solution - uses same hardware as WEP - but uses TKIP encryption
Data and voice over native vlan no QOS and no 802.1p trunk

13. What is layer 2 roaming?
It is enabled by default on all CEF capable switches
If the client maintains the same IP address as it roams between Aps. All must have same VLAN - SSID - and subnet
Because each frame is checked
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

14. How is root port decided upon?
Once the CCM gives them the parameters - they use RTP
Lowest cumulative cost to root
FIB
LWAPP (Cisco proprietary) and CAP-WAP (standards based)

15. How is DHCP snooping enabled (scope)?
Automatically by duplex mode in use. Full duplex are point ot point. Half duplex ports use traditional 802.1D convergence is used.
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated
They disguise the origin of an attack
Globally

16. EAP encryption
Dynamic arp inspection
No because they only participate if asked
Dynamic WEP keys that change periodically
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack

17. How does the VRRP master router handle the VIP?
The master router can share the VIP
Effectively stops STP on filtered ports
The port is forced to always authorize any connected client with no authentication necessary (default)
All user ports that have portfast enabled

18. How does PAgP form etherchannels?
Only for the offending VLAN on the port
Connects with SONET or SDH
For hosts that doesn't understand routing - the DGW is configured to reply with its own mac
Only on ports that have same static VLANs or trunking. It also modifies parameters of the channel if one of the ports is modified

19. What are the 3 trunk encap modes?
1- trunking mode - 2-trunk encapsulation - 3-native VLAN - 4-allowed VLAN
Isl - dot1q - negotiate (default)
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
FE and GE

20. What does port-security protect do?
Change in trunk encap
Port stays up - packets from violating MACs dropped - no logging
On all switches in network to enable RLQ request and reply
Switching Database Manager - configures and prunes TCAM partitions

21. What are dynamic VLANs based on?
Almost eliminates listening and learning states for single hosts on an access link
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
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
MAC of the end device

22. What is a CEF glean?

23. What is SSO?

24. What is the cost of a 100Mbps link?
MAC of the end device
19
4
Isl - dot1q - negotiate (default)

25. What is DSCP codepoint AF21(18)?
Immediate (class 2)
Option 43
Globally
Multicast to 01-80-c2-00-00-00

26. What are the 2 UDLD modes?
Feature Manager - after the ACL is created - the FM compiles the ACEs into the table
Group (0-255) - priority (1-254 254 is highest - 100 default)
Normal and aggressive
RPR - RPR+ - and SSO

27. What is a punt adjacency?
Isl - dot1q - negotiate (default)
1-(opt) set system priority - 2-select interface(s) - 3-assign the protocol - 4-set the mode - 5-(opt) set the port priority
Checks the source MAC in the header against the sender MAC in the ARP reply
Packets must be sent to the L3 engine for further processing

28. What must the other end be set to if PAgP desirable or LACP active mode is selected?
LACP port priority
Switch(config-if)# vrrp xx where xx= group number
Either desirable or auto mode
Stateful switchover - redundant sup is fully booted and init'd. Both start and run config are synched as is L2 information - and switchinterfaces.

29. What are the gotchas for uplinkfast?

30. What are the 6 HSRP states?
7 switches from root bridge
Disabled - init - listen - speak - standby - active
5 (0-4 with 4 being the highest)
1 to 64

31. How are frames forwarded across a specific link?
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.
Can hear only BDPUs
Hashing algorithm
Once the CCM gives them the parameters - they use RTP

32. 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
Trunk
3 seconds. Holdtime =3 hellos + 1
L2

33. How do you configure a DHCP gateway?
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
From the DHCP snooping database or from static entries
Hashing algorithm
First configure a L3 interface in same VLAN as clients - then use the ip helper-address command to ID the DHCP server

34. 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
Effectively stops STP on filtered ports
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
Configuration and TCN

35. What does the static keyword do when applying an arp ACL?
Prevents the dhcp binding DB from being checked.
The number of times the entry has been updated since the table was generated
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
The topology is pre-populated by downloading the topology DB into the FIB and dynamically updated. Called Cisco Express Forwarding

36. How do IP phones communicate with each other?
Another router must have a higher HSRP priority and have preemt set up
Port
Reboots and searches for a new WLC
Once the CCM gives them the parameters - they use RTP

37. How far chould a VLAN extend?
Immediate (class 2)
Distribution layer
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
When each AP stands alone within the larger network.

38. What is errdisable dtp-flap?
Change in trunk encap
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another
1 IP subnet
By using a hash of a key string

39. What is the access layer best practice?
All L2 connectivity should be contained within the access layer.
1/2 and 3/6
When each AP stands alone within the larger network.
80% of the user traffic should stay in the VLAN

40. What is a null adjacency?
Priority (class 1)
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure
Real-time functions such as beacons and probes - encryption and interactions with the client at L2
Used to switch packets destined for the null interface

41. How does packet forwarding work
All nondesignated ports - but ok for all ports
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
Untrusted
Arp for local subnet - if on different subnet - will arp for dgw

42. what I s distributed CEF (dCEF)?
The total delay from start to finish
Used when ACLs specify port ranges...used by TCAM
CEF is distributed completely among multiple L3 forwarding engines.
When the AP uplinks to an Ethernet network.

43. When a host is connected to a switchport - why aren't frame errors propagated?
Checks the source MAC in the header against the sender MAC in the ARP reply
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
Show standby
Because each frame is checked

44. How does every GLBP command begin
Use the spanning-tree root macro
Switch(config-if)# glbp xx where xx = group number
Very high L3 throughput - no access lists or port filtering - redundancy and resilience - advanced QoS
Port stays up - packets from violating MACs dropped - no logging

45. What is a QoS trust boundary?
The point at which a switch decides to trust incoming Qos. Usually at boundary with ISP
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
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
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz

46. Which ports should you consider trusted for DAI?
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
L2
Those that connect to other switches
Up to 54Mbps - not cross-compatible - 12 to 23 clean channels - 5.8 Ghz

47. How many potential links can LACP define?
3 seconds. Holdtime =3 hellos + 1
16 - of which up to 8 are active. The others are in standby
2 strand MMF with MT-RJ or SC connectors
FE and GE

48. What is layer 3 roaming?
Weak key rotation
1 second. Backup routers can learn the interval from the master
When a client roams between Aps in different subnets
Disabled - blocking - listening - learning - forwarding

49. What is a wireless mobility group?
7 switches from root bridge
Port with alternative path to root less desirable than root
Variation in delay
A client can roam to any WLC as long as it stays in a mobility group

50. What do you need to determine to use MSTP?
By creating a static IP binding
All nondesignated ports - but ok for all ports
The number of STP instances needed ot support the desired topologies and whether to map a set of VLANs to each instance
The standby becomes active and stays active by default. Preemption can be configured