Spanning Tree

By | 05/02/2015

Types of spanning tree:

CST – Common Spanning Tree – 802.1q

RSTP – Rapid Spanning Tree – 802.1w

PVST – Per Vlan Spanning Tree – Creates one instance per VLAN and STP is run for each VLAN.

MST – Multiple Spanning Tree – 802.1s – It’s possible to define the number of instances and which VLANs belong to each STP instance. For topologies with lots of VLANs, MST allows to run only on instance for those VLANs that will have the same topology.

 

References:

http://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/24248-147.html

 

 

Switch BPDU options

spanning-tree bpdu guard – If a switch is connected in the port and it receives bpdu traffic, the port will be set at err-disabled state

spanning-tree bpdufilter enable – The port won’t sent any bpdu through the interface. No Spanning Tree protection on this port.

spanning-tree guard root – If the port receives a superior bpdu, root guard sets the port in a root-inconsistent STP state

 

err-disable recovery options

Switch(config)# errdisable recovery cause bpduguard

Switch(config)# errdisable recovery interval 30

 

References:

 http://www.securityartwork.es/2015/05/25/defensas-frente-a-ataques-stp/