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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. How many MST instances can be in a region?
Gateway load balancing protocol - cisco proprietary
When a port moves into forwarding or from fowarding or learning to blocking.
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
Causes switch to actively determine whether alternative paths exist to root bridge in case ther eis an indirect failure

2. How do you disable DTP when you configure both ends of the ISL manually?
Switchpotrt nonegotiate
Auto mode
Per-port or globally for all fiber-optic ports. Can be enabled globally - but will only affect fiber ports
1500B

3. What is the LACP priority range?
1-65535 (def 32768) lower priority - higher probability
Will trunk if asked
On by default
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds

4. How many potential links can LACP define?
All fiber-optic links between switches (must be enabled on both ends)
Configure the timer on the AVG and let it propagate
16 - of which up to 8 are active. The others are in standby
Trusted or untrusted

5. How does UDLD work?
Configuration and TCN
12 kbps with headers and compression
By brining up a tunnel between them to carry 802.11 related messages and client data.
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD

6. What is the 80/20 rule?
Backbonefast uses RLQ to determine if upstream switches have stable connections to root bridge
80% of the user traffic should stay in the VLAN
2 strand MMF with MT-RJ or SC connectors
Via an 802.1Q trunk or a single VLAN access port

7. Define GLBP
A client can roam to any WLC as long as it stays in a mobility group
If a unidirectional link is detected - the port continues normally - but the port is marked as undetermined and a syslog is generated
Gateway load balancing protocol - cisco proprietary
Can send and receive BDPUs

8. What is the traditional MLS view of switching?
By sending a gratuitous ARP
The number of times the entry has been updated since the table was generated
By an ARP access list that defines the permitted bindings
Route once - switch many

9. How does every GLBP command begin
Switch(config-if)# glbp xx where xx = group number
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
1 to 64
Some unused bits are used to allow a port to identify its role and state. Also the BDPUs state that they are V2 BDPUs

10. What method of QOS does voice traffic use most frequently?
Root
MAC addresses are learned from the source MAC of incoming frames. If the destination address is unknown - the frame is flooded out all except the receiving port.
Differentiated services
Each frame transmits its expected duration time

11. If the WLC connects to an Etherchannel - how should the channel be configured and why?

12. What 2 conditions does IP source guard check for?
224.0.0.2 (all routers)
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
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
Source IP and MAC must match those addresses learned by DHCP snooping or a static entry

13. How should the switch port to which a LAP be configured?
Access
Port that connects to another switch and becomes a designated port
All L2 connectivity should be contained within the access layer.
MST attributes must be manually entereed on each switch in the region. They don' t propagate like VTP.

14. 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
MAC addresses are learned from the source MAC of incoming frames. If the destination address is unknown - the frame is flooded out all except the receiving port.
16 - IST gets MSTI 0 - 1-15 are available for use. MSTIs are locally significant to the MST region
4

15. How is RSTP synchronization accomplished?
Routers are assigned to common GLBP group. All routers can be active and can load balance
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another
Traffic types and patterns - amount of L3 switching cap. At dist. Layer - # users at access layer - geography - size of spanning tree domains
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root

16. How does uplinkfast handle changes in topology?
A router keeps a routing table and an ARP table. The FIB combines them for every next-hop entry
Every switch and router in a network must be configured with appropriate QoS features and policies
Round robin - weighted - or host-dependent
Notifies upstream neighbors by sending multicasts on behalf of hosts at the interval of the max update rate parameter.

17. What is 802.1x force-authorized?
Can send and receive BDPUs
The port is forced to always authorize any connected client with no authentication necessary (default)
RADIUS
FE and GE

18. What scope is 802.1x enabled?
RPR - RPR+ - and SSO
Globally
300 sec by default
Differentiated services

19. What is DSCP codepoint AF31(26)?
Trunk
Frames that barely exceed 1518B or 1622B due to headers
Flash (class 3)
Trunk

20. What are the characteristics of the distribution layer?
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
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
All user ports that have portfast enabled
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links

21. How does GLBP work?
The standby becomes active and stays active by default. Preemption can be configured
Routers are assigned to common GLBP group. All routers can be active and can load balance
By an ARP access list that defines the permitted bindings
Port stays up - packets from violating MACs dropped - no logging

22. What is a cell?

23. Which 4 things must be agreeable to trunk?
Real-time Transport Protocol
Routers at the distribution layer become the bottlenecks or broadcast or multicast traffic slows the switches in the switch block
1- trunking mode - 2-trunk encapsulation - 3-native VLAN - 4-allowed VLAN
The frame tag contains a 3 but portion tagged from 0 (low) to 7 (high)

24. What is dynamic desireable?
Per VLAN
Automatically negotiates a common trunk mode between switches
Reboots and searches for a new WLC
The port asks the other end to trunk

25. Does a WLC and a LAP need to be on the same subnet?
Used to switch packets that can't be forwarded normallly due to an encapsulation failure - unresolved address - unsupported protocol - etc.
No
The active router. All other routers are in backup state
Priority (class 1)

26. How does VRRP do tracking?

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

28. What is an indirect topology change?
Discarding - learning - forwarding
Roughly 50%
Any dhcp reply coming from an untrusted port is discarded and the offending port is put in errdisable
The link status stays up - but something between them has failed or is filtering traffic

29. What is accelerated CEF (aCEF)?
Aggregation - high L3 throughput - security and policy based connectivity functions through access lists and packet filters - QoS - scalable high-speed links
Group (0-1023) priority (1-255 higher better def 100)
0000.5e00.01xx
CEF is distributed across multiple L3 forwarding engines - typically on Catalyst 6500 line cards each having only a subset

30. What is layer 3 roaming?
TCAM
Disabled - init - listen - speak - standby - active
When a client roams between Aps in different subnets
Configure non-silent submode

31. If a wireless station needs to transmit and another device is transmitting - what happens?
Sends special layer 2 UDLD frames and expects an echo. Both ends must be configured for UDLD
Flash (class 3)
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting
The same as a standby group in HSRP

32. What does Root Guard do?
It updates the L2 headers with the proper src and dst MAC - L3 TTL - L3 checksum - and L2 checksum information
80% of the user traffic should stay in the VLAN
Controls where candidate root bridges can be connected and found on a network
Root

33. How can BDPU Guard be configured?
When the size of a cell is intentionally reduced
All non-edge ports are discarding. After the root bridge is identified - the port with superior BDPU becomes root
Globally or per-port
Yes

34. How do you prevent VLAN hopping?
The distribution layer should have only L3 links
Completed dhcp bindings - mac addresses - IP addresses - etc.
Automatically by duplex mode in use. Full duplex are point ot point. Half duplex ports use traditional 802.1D convergence is used.
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

35. What duplex setting does 802.11 use and why?
Discarding - learning - forwarding
A VLAN that spans the entire fabric
Half because transmitting and receiving stations use the same frequency
Connects with SONET or SDH

36. Does GLBP allow preemption?
The priority is a 2 byte value followed by the MAC that decides which ports are actively participating in Etherchannel (lower=higher priority)
Yes
4
On ports where you never expect to find a root bridge for a VLAN

37. What does port-security restrict do?
Port stays up - but packets from violating MACs are dropped. Switch logs violating packets
They must be carried over a voice VLAN (VVID) or over a regular data VLAN (ie. The native VLAN or the PVID)
Plain text or md5
802.1x with EAP over LAN (EAPOL)

38. What is DSCP?
Frames that barely exceed 1518B or 1622B due to headers
Differentiated services code point
Roughly 50%
Switchpotrt nonegotiate

39. When a host is connected to a switchport - why aren't frame errors propagated?
Using a mobility exchange message
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.
Because each frame is checked
Show standby

40. Where is root guard enabled?

41. What format does the GLBP MAC use?
Every switch and router in a network must be configured with appropriate QoS features and policies
Packets are discarded due to an ACL or policy action
0007.b4xx.xxyy where xx.xx is six 0 bits followed by a 10-bit GLBP group numberr. Yyyy is the virtual forwarder number
It is enabled by default on all CEF capable switches

42. What are the RSTP port roles?
1-client sends DHCP discover as broadcast - 2-DHCP server sends DHCP offer - client sends DHCP Request - DHCP server sends DHCP ack
Root - designated - alternate - and backup
Switch(config-if)# vrrp xx where xx= group number
Globally

43. What is best effort delivery QOS?
Switches make an effort to move packets as quickly as possible
Using a mobility exchange message
1 to 64
Switching Database Manager - configures and prunes TCAM partitions

44. What functions does a WLC perform?
Best effort delivery - integrated services model - and differentiated services model
Control functions
The link status stays up - but something between them has failed or is filtering traffic
The station must wait until the frame in progress has completed - then wait a random amount of time before transmitting

45. What are the 3 ways GLBP load-balances?
When each AP stands alone within the larger network.
Round robin - weighted - or host-dependent
2 strand MMF with MT-RJ or SC connectors
A client can roam to any WLC as long as it stays in a mobility group

46. How does RSTP converge?
Distribution layer
4
Collision domain
If a proposal is received - the recipient isolates - all nonedge ports blocked until proposal sent causing neighbors to synch - which propagates out in waves

47. What does the src-mac option do when checking ARP replies
Switch(config-if)# glbp xx where xx = group number
They shorten their bridge table aging times from default (300sec) to the fowarding delay (15 sec)
The time interval that a switch stores a DBPU before discarding it. Default 20 seconds
Checks the source MAC in the header against the sender MAC in the ARP reply

48. What is route caching?

49. RSTP edge port
Only a single host connects . If one BDPU is received - it is no longer an edge port
Globally
Port with best root path cost
Root - designated - alternate - and backup

50. 802.11g
Isolated and community
80% of the user traffic should stay in the VLAN
Port that connects to another switch and becomes a designated port
Compatible with 802.11b - up to 54Mbps in 12 data rates - 3 channels - 2.4Ghz