Module 5-6
What additional information is contained in the 12-bit extended system ID of a BPDU?
VLAN ID The BPDU has three fields; the bridge priority, the extended system ID, and the MAC address. The extended system ID contains 12 bits that identify the VLAN ID.
Which three port states are used by Rapid PVST+? (Choose three.)
1. Forwarding 2. Learning 3. Discarding
In which two PVST+ port states are MAC addresses learned?
1. Forwarding 2. Learnings
Which three are LACP interface modes? (Choose three.)
1. On 2. Active 3. Passive
Which three are PAgP interface modes? (Choose three.)
1. On 2. Auto 3. Desirable
Which is the default STP operation mode on Cisco Catalyst switches?
PVST+
Which protocol was designed to bring faster convergence to STP?
RSTP (Rapid Spanning Tree Protocol)
Which two concepts relate to a switch port that is intended to have only end devices attached and intended never to be used to connect to another switch? (Choose two.)
1. Edge port 2. PortFast
Which combinations of PAgP modes will form an EtherChannel?
1. Auto > Desirable 2. On > On
What are two advantages of EtherChannel?
1. Configuring the EtherChannel interface provides consistency in the configuration of the physical links. 2. Spanning Tree Protocol views the physical links in an EtherChannel as one logical connection. EtherChannel configuration of one logical interface ensures configuration consistency across the physical links in the EtherChannel. The EtherChannel provides increased bandwidth using existing switch ports without requiring any upgrades to the physical interfaces. Load balancing methods are implemented between links that are part of the same Etherchannel. Because EtherChannel views the bundled physical links as one logical connection, spanning tree recalculation is not required if one of the bundled physical links fail. If a physical interface fails, STP cannot transition the failed interface into a forwarding state.
Which two parameters must match on the ports of two switches to create a PAgP EtherChannel between the switches?
1. Speed 2. VLAN information For an EtherChannel to be created, the ports that are concerned on the two switches must match in terms of the speed, duplex, and VLAN information. The PAgP mode must be compatible but not necessarily equal. The port ID and the MAC addresses do not have to match.
Which two statements describe a switch port that is configured with PortFast? (Choose two.)
1. The switch port immediately transitions from blocking to the forwarding state 2. The switch port should never receive BPDUs
What are three advantages of using EtherChannel technology?
1. There is no need to upgrade links to faster connections to increase bandwidth. 2. A Spanning tree recalculation is not required when a single link within the channel goes down. 3. Configuration tasks can be done the EtherChannel interface.
Which three interface parameters must match for an EtherChannel to form?
1. allowed VLANs 2. Trunking mode 3. Native VLAN
During the implementation of Spanning Tree Protocol, all switches are rebooted by the network administrator. What is the first step of the spanning-tree election process?
All the switches send out BPDUs advertising themselves as the root bridge.
How often does a switch send a BPDU(Bridge Protocol Data Unit)?
BPDUs are send every 2 seconds by default.
Which PAgP interface mode will initiate negotiation with other interfaces?
Desirable Only the PAgP Desirable mode initiates negotiations. On and Auto modes do not.
Which statement is true about EtherChannel technology?
EtherChannel uses existing switch ports.
A switch is configured to run STP. What term describes a field used to specify a VLAN ID?
Extended system ID
What is a characteristic of spanning tree?
It is enabled by default on Cisco switches.
When PVST is running over a switched network, which port state can participate in BPDU frame forwarding based on BPDUs received, but does not forward data frames?
Listening. Ports in the blocking state are nondesignated ports and do not participate in frame forwarding. Ports in the listening state can participate in BPDU frame forwarding according to received BPDU frames, but do not forward data frames. Ports in the forwarding state forward data frames and send and receive BPDU frames. Ports in the disabled state are administratively disabled.
What value determines the root bridge when all switches connected by trunk links have default STP configurations?
MAC Address.
Which protocol provides up to 16 instances of RSTP, combines many VLANs with the same physical and logical topology into a common RSTP instance, and provides support for PortFast, BPDU guard, BPDU filter, root guard, and loop guard?
MST MST is the Cisco implementation of MSTP, an IEEE standard protocol that provides up to 16 instances of RSTP and combines many VLANs with the same physical and logical topology into a common RSTP instance. Each instance supports PortFast, BPDU guard, BPDU filter, root guard, and loop guard. STP and RSTP assume only one spanning-tree instance for the entire bridged network, regardless of the number of VLANs. PVST+ provides a separate 802.1D spanning-tree instance for each VLAN that is configured in the network.
What is the outcome of a Layer 2 broadcast storm?
New traffic is discarded by the switch because it is unable to be processed. When the network is saturated with broadcast traffic that is looping between switches, new traffic is discarded by each switch because it is unable to be processed.
Which technology solves the problem of a device being unable to get an IPv4 address from a DHCP server due to STP forwarding delay timers?
When enabled on a switch port, PortFast allows a port to transition from blocking to forwarding state immediately so that DHCP client requests are not delayed reaching the DHCP server. You
By default (without any configuration on a switch), what will determine which switch is the root bridge?
Without configuration changes, all switches will have the default STP priority of 32,768. If all priorities are the same, the switch with the lowest MAC address value will become the root bridge.