Spanning Tree Protocol Flashcards
How many different BPDU types are there?
Two types
Configuration BPDU
Topology Change notification BPDU
All ports on a root bridge are assigned what role?
Designated port
How dose a port stay in the blocking, listen, learning states with default values
Blocking state is 20 seconds
Listening and learning are 15 seconds each
What spanning tree Protocol is 802.1s
MST
What spanning tree Protocol is 802.1w
RSTP
What spanning tree Protocol is 802.1D
802.1D is the original stp. It was a single spanning tree instances that covered all vlans.
Pvst is the modern version of this and allows for a per spanning tree instance for each vlan.
What dose a port do in the blocking state.
Blocking: the port is enabled, but the port is not forwarding any traffic to prevent loops. In this state the switch will not learn MAC address on this port. It will however revive BPDU listening for topology changes.
With the default settings the port will remain in this state for 20 seconds before moving into the listing state when a topology change takes place.
Describe the listing state.
Once The port transitions from the blocking state to the listing state it can now send BPDUs. It still cannot forward any network traffic. It will remain in this state for 15 seconds before moving to the learning state.
Describe the learning state.
The port can now learn MAC address and update the Mac table . It can send and receive BPDUs but will not forward any network traffic yet. It will remain in the learning state for 15 seconds before moving to the forwarding state.
Describe the forwarding state.
The port can now forward all traffic.
How long does it take a port to forward in pvst.
The initialization time take 30 seconds for a new port to move into forwarding. 15 seconds for listing and 15 seconds for learning.
How long does it take a port to go from blocking to forwarding in PVST
50 seconds
20 for blocking 15 for listing and 15 for learning.
What is a root port
A port that connects to a root bridge or an upstream switch in the spanning tree topology. Their is only one root port per switch per vlan.
What is a designated port.
A port that can send and receive BPDUS frames to other switches . They provide connections to down stream devices. There’s only one DP per link.
What is the root bridge
The root bridge is the king switch for that spanning tree topology all its ports are in a forwarding state and its the one that dictates topology changes.
