CCNA DC FAQ: Cisco Nexus Spanning Tree Protocol Implementation
Figure: Typical Configuration Choice: Making the Distribution/Aggregation Switch Be Root
Q1. On a Nexus switch, which of the following commands change the value of the bridge ID? (Choose two answers.)
a. spanning-tree bridge-id value
b. spanning-tree vlan vlan-number root {primary | secondary}
c. spanning-tree vlan vlan-number priority value
d. set spanning-tree priority value
Q2. Examine the following extract from the show spanning-tree command on a Cisco Nexus switch:
Spanning tree enabled protocol rstp Root ID Priority 8193 Address c84c.75fa.601e This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 8193 (priority 8192 sys-id-ext 1) Address c84c.75fa.601e Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Interface Role Sts Cost Prio.Nbr Type ---------- ---- --- --------- -------- -------------------------------- Po15 Desg FWD 1 128.4110 (vPC) P2p Po16 Desg FWD 1 128.4111 (vPC) P2p
Which of the following answers is true about the switch on which this command output was gathered?
a. The information is about the STP instance for VLAN 1.
b. The information is about the STP instance for VLAN 3.
c. The command output confirms that this switch cannot possibly be the root switch.
d. The command output confirms that this switch is currently the root switch.
Q3. A switch’s Eth1/1 interface, a trunk that supports VLANs 1–10, has a speed of 10 Gbps. The switch currently has all default settings for STP. Which of the following actions result in the switch using an STP cost of 2 for that interface in VLAN 3? (Choose two answers.)
a. spanning-tree cost 2
b. spanning-tree port-cost 19
c. spanning-tree vlan 3 port-cost 19
d. Adding no configuration
Q4. An engineer configures a switch to put interfaces Eth1/1 and Eth1/2 into the same PortChannel. Which of the following terms is used in the configuration commands?
interface port-channel1 switchport mode trunk mtu 9216 vpc 1
a. Port-Channel
b. Virtual PortChannel
c. Ethernet-Channel
d. Channel-group
Q5. Switch SW3 is receiving only two hello BPDUs, both from the same root switch, received on the two interfaces listed as follows:
SW3# show interfaces status Port Name Status Vlan Duplex Speed Type Eth1/13 connected 1 full 10G 10Gbase-SR Eth1/1 connected 1 full 10G 10Gbase-SR
SW3 has no STP-related configuration commands. The hello received on Eth1/13 lists root cost 10, and the hello received on Eth1/1 lists root cost 20. Which of the following is true about STP on SW3?
a. SW3 will choose Eth1/13 as its root port.
b. SW3 will choose Eth1/1 as its root port.
c. SW3’s Eth1/13 will become a designated port.
d. SW3’s Eth1/1 will become a designated port.
Q6. Which of the following commands list a nonroot switch’s root cost? (Choose two answers.)
a. show spanning-tree root
b. show spanning-tree root cost
c. show spanning-tree bridge
d. show spanning-tree