CCNA: STP/RSTP

1 minute read

Description:

STP Commands. See here
Bridge Priority = Switch Priority 32768 / MAC address

STP/RSTP Global Commands:

   Switch(config)#spanning-tree mode [pvst | rapid-pvst] # usually rapid-pvst is chosen. PVST+ is the default.
   Switch(config)#spanning-tree vlan 1-4094 priority 32768 # sets the default priority. Has to increment in 32768 blocks.
   Switch(config)spanning-tree vlan 10 root primary # only run this on the root switch. Changes priority to 1 increment lower than the lowest Bridge id.
   Switch(config)spanning-tree vlan 10 root secondary # only run this on the switch you want as a backup to the root. Changes priority to 16384.
   Switch(config)#spanning-tree vlan 1-4094 hello-time 2 # sets the hello timers to 2 seconds. This is the default.
   Switch(config)#spanning-tree vlan 1-4094 forward-time 15 # sets the forward timers to 15 seconds. This is the default.
   Switch(config)#spanning-tree vlan 1-4094 max-age 20 # sets the max age timers to 20 seconds.This is the default.
   Switch(config)#spanning-tree gaurd [loop|root|none] # enables root gaurd/ loop gaurd
   Switch(config)#spanning-tree backbonefast #enables backbonefast
   Switch(config)#spanning-tree uplinkfast # enables uplinkfast
   Switch(config)#spanning-tree extend system-id # Used for a system that supports 1024 MAC addresses instead of the default 64.
   Switch(config)#spanning-tree bpdugaurd default # sets bpdugaurd as default. Then to disable per interface, just run "spanning-tree bpdugaurd disable"

STP/RSTP Interface Commands:

   Switch(config)#int g0/1
   Switch(config-if)#spanning-tree [vlan 1-4094] port-priority 128 # this is the default. It goes from 0-240 in increments of 16.
   Switch(config-if)#spanning-tree link-type [point-to-point|shared] # manual link specification, not required
   Switch(config-if)#spanning-tree [vlan 1-4094] cost 19
   Switch(config-if)#spanning-tree bpduguard enable # enables bpdugaurd. Good for PCs but bad for WAPs/Switches because it blocks BPDUs.
   Switch(config-if)#spanning-tree bpdufilter enable # enables bpdufiltering
   Switch(config-if)#spanning-tree portfast # enables portfast which disables STP.
   Switch(config-if)#no spanning-tree vlan # disables spanning-tree

Cisco way to enable RSTP:

   Switch# config t
   Switch(config)# spanning-tree mode rapid-pvst
   Switch(config)# int fa 6/4
   Switch(config-if)# spanning-tree link-type point-to-point
   Switch(config-if)# end
   Switch(config)# end
   Switch# clear spanning-tree detected-protocols

Show Commands:

   show spanning-tree
   show spanning-tree summary
   show spanning-tree root
   show spanning-tree bridge
   show spanning-tree detail
   show spanning-tree interface
   show spanning-tree vlan
   debug spanning-tree events

Tags:

Categories:

Updated:

Comments