Spanning Tree Protocol

Question 1

Defined by the IEEE 802.1D standard “Loop Prevention Protocol”, which could lead to symptoms such as broadcast storms, network crashes, and MAC address table corruption. This runs on most modern switches by default
Rada Perlman Inventor of STP
STP by default is turned on in the switch

Answer 1

Spanning Tree Protocol (STP)

Question 2

Switches talk to each other and build a map of the tree. Switches “Block” redundant ports between other switches having only one path and no loops

Answer 2

Switches

Question 3

Used by switches to share information with other switches that are participating in the Spanning-Tree Protocol
Contains switch MAC Address and STP Priority Value (Bridge ID) lowest Bridge ID = Root Bridge

Answer 3

Bridge Protocol Data Unit (BPDU)

Question 4

If there is a lot of hosts it is best to manually elect the Root Bridge (lowest Bridge ID)

Answer 4

Best practice on STP

Question 5

Root Bridge is the “Root” of the Spanning Tree
All paths lead back to the Root Bridge (lowest Bridge ID)
Switches “Block” the Port that has the highest path cost
Higher Path Cost = slower link
Lowest Path Cost = faster link

Answer 5

Root Bridge

Question 6

Faster than the classic spanning-tree
classic STP could take 30 to 50 seconds to converge
Due to ports states: Listening, Learning, Blocking, Forwarding
RSTP has less port states and faster convergence
Discarding, Learning, Forwarding

Answer 6

Rapid Spanning Tree Protocol (RSTP)

Question 7

is the most recent evolution of these protocols (Used in larger data centers)

Answer 7

Shortest Path Bridging (SPB)

Question 8

Multiple Spanning Tree Protocol (MSTP) and Per-VLAN Spanning Tree Protocol (PVST)

Answer 8

Other versions & modes of STP