3 - STP Implementation Flashcards
Ch 3
Commands to manually configure an Etherchannel?
- Int fa0/14
- channel-group 1 mode on
- int fa0/15
- channel-group 1 mode on
What two other terms are synonymous with Etherchannel?
Port-channel and Channel-group
What two protocols does Cisco support to negotiate an Etherchannel?
- Cisco-proprietary Port Aggregation Protocol (PAgP)
- IEEE standard Link Aggregation Control Protocol (LACP)
What is the IEEE standard for LACP?
802.3ad
What are the two key words that enable PAgP?
desireable and auto
What are the two key words that enable LACP?
active and passive
show’ cmds to view an Etherchannel?
- show etherchannel 2 port-channel
- show etherchannel 2 summary
- show spanning-tree vlan 3
What is the command to move from STP to RSTP?
spanning-tree mode rapid-pvst
What is the command to implement 802.1d STP?
spanning-tree mode pvst
What is 802.3ad?
The IEEE standard for LACP
What mode of spanning-tree is the default?
pvst or 802.1d
What ‘show’ cmds will display the version of spanning-tree
- show spanning-tree vlan 10
- show spanning-tree vlan 10 bridge
What ‘show’ cmd displays alternate and backup interfaces whether RSTP is running or not?
show spanning-tree vlan 10
What is the only ways to determine which version of spanning-tree is running?
- You must look at the ‘spanning-tree mode’ command in the configuration.
- show spanning-tree vlan 10 bridge
What does ‘spanning-tree mode mst’ do?
Creates multiple RSTP instances but does NOT require one instance per VLAN.
What is the RSTP term for Blocking?
Discarding
What will ‘show’ cmds display for a port that is Discarding?
Blocking
What ‘show’ cmd will display the STP state of an interface?
show spanning-tree vlan 10 interface gig0/1 state
What two interface conditions tells RSTP what type of port it is?
duplex and portfast
How would RSTP identify and shared port?
half-duplex without portfast configured
What type of RSTP port would be half-duplex with portfast configured
shared-edge
What type of RSTP port would be full-duplex with portfast configured?
point-to-point edge
What type of RSTP port would be full-duplex without portfast configured
point-to-point (between two switches)
What show command will display the type of RSTP port whether RSTP is running or not?
show spanning-tree vlan 10 Loc: 3190
What two versions of RSTP do Cisco switches support?
- Rapid PVST
- Multiple Spanning-tree
What is the command to implement mst?
spanning-tree mode mst Loc: 3190
What are the fields of the BID with the System Extension?
Priority 4-bits, System ID Extension 12-bits holding VLAN #, System ID (MAC) 6-bytes Loc: 3225
What is the interface cmd for changing a port cost on a switch for a specific VLAN?
spanning-tree vlan 10 cost 30 Loc: 3382
What show cmd will display the port cost?
show spanning-tree vlan 10’
What is the cmd for changing the priority of a switch?
spanning-tree vlan 10 priority
What is the cmd for making a switch to Root Bridge?
spanning-tree vlan 10 root primary
What is the cmd for making a switch a backup to the Root Bridge?
spanning-tree vlan 10 root secondary
If the command ‘spanning-tree vlan 10 root primary’ is used what priority value will it assign?
If current root base priority higher than 24576 then 24576. If lower then highest multiple of 4096 that is lower than current root. Loc: 3382
If the command ‘spanning-tree vlan 10 root secondary’ is used what priority value will it assign?
28672 Loc: 3434
What is the base priority?
32768 Loc: 3434
What show command will show the local switches BID and Priority
show spanning-tree vlan 10 bridge Loc: 3434
What show command will show the Root Bridge BID and Priority without having to be on the Root switch?
show spanning-tree vlan 10 root Loc: 3434
What is the command to enable portfast on an interface?
spanning-tree portfast Loc: 3532
What is the command to enable bpdu guard?
spanning-tree bpduguard enable Loc: 3532
what is the command to enable portfast globally?
spanning-tree portfast default Loc: 3532
What is the command to enable bpdu guard globally
spanning-tree portfast bpduguard default Loc: 3840
What are the commands to disable bpdu guard and portfast on an interface?
spanning-tree portfast disable, spanning-tree bpduguard disable Loc: 3532
What is the show command to view the global state of bpdu guard and portfast
show spanning-tree summary
What is the interface cmd for changing its port cost for all VLANs on that interface?
spanning-tree cost 19
When configuring Etherchannel do you need to create a Logical Port-channel Interface?
No.
In RSTP how do you identify the Alternate port?
- show spanning-tree vlan 10
- then look below at port for Altn
What 3 options can follow the ‘spanning-tree mode ‘ command?
- pvst
- mst
- rapid-pvst
Of the 3 options that can follow the ‘spanning-tree mode’ command which two are RSTP?
- rapid-pvst
- mst
If a port is configured as Half Duplex with portfast enabled what type of port does RSTP consider it to be?
Shared Edge port
What command will change the port cost?
- interface gig0/1
- spanning-tree vlan 10 cost 16