EXOS VM 22.6.1.4:

!!!!  NOTE: Spanning Tree default changed in ExtremeXOS 22.2  !!!!

Multiple Spanning Tree Protocol (MSTP) is enabled by default to prevent broadcast storms

Would you like to disable MSTP? [y/N/q]:

* EXOS-VM.3 # show stpd
MSTP Global Configuration:
MSTP Region Name        : 0c7216bd8e00
MSTP Format Identifier  : 0
MSTP Revision Level     : 3
MSTP Digest             : ac:36:17:7f:50:28:3c:d4:b8:38:21:d8:ab:26:de:62
Common and Internal Spanning Tree (CIST)        : s0
Total Number of MST Instances (MSTI)            : 0

Name       Tag  Flags  Ports Bridge ID        Designated Root  Rt Port Rt Cost
s0         0000 EM—-    12 80000c7216bd8e00 80000c7216bd8e00 ——-       0

Total number of STPDs: 1                STP Flush Method: VLAN and Port
STP BPDU Forwarding: On
STP Multicast Send IGMP or MLD Query: On

Flags: (C) Topology Change, (D) Disable, (E) Enable, (R) Rapid Root Failover
(T) Topology Change Detected, (M) MSTP CIST, (I) MSTP MSTI

* EXOS-VM.5 # show stpd detail

Stpd: s0                Stp: ENABLED            Number of Ports: 12
Rapid Root Failover: Disabled
Operational Mode: MSTP                  Default Binding Mode: 802.1D
MSTI Instance:  CIST
802.1Q Tag: (none)
Ports: 1,2,3,4,5,6,7,8,9,10,
11,12
Participating Vlans: Default
Auto-bind Vlans: Default
Bridge Priority            : 32768              Bridge Priority Mode: 802.1t
Operational Bridge Priority: 32768
BridgeID                   : 80:00:0c:72:16:bd:8e:00
Designated root            : 80:00:0c:72:16:bd:8e:00
CIST Root                  : 80:00:0c:72:16:bd:8e:00
CIST Regional Root         : 80:00:0c:72:16:bd:8e:00
External RootPathCost      : 0  Internal RootPathCost: 0
Root Port   : —-
MaxAge      : 20s       HelloTime     : 2s      ForwardDelay     : 15s
CfgBrMaxAge : 20s       CfgBrHelloTime: 2s      CfgBrForwardDelay: 15s
RemainHopCount: 20      CfgMaxHopCount: 20
Topology Change Time           : 35s            Hold time        : 1s
Topology Change Detected       : FALSE          Topology Change  : FALSE
Number of Topology Changes     : 0
Time Since Last Topology Change: 0s
Topology Change initiated locally on Port none
Topology Change last received on Port none from none
Backup Root               : Off         Backup Root Activated  : FALSE
Loop Protect Event Window : 180s        Loop Protect Threshold : 3
New Root Trap             : On          Topology Change Trap   : Off
Tx Hold Count             : 6
Participating VLANs:
VLAN                                     Tag    Number of Ports
Ports
——————————————————————————-
Default                                  1      12
1(F),2(F),3(F),4(F),5(F),6(F),7(F),8(F),
9(F),10(F),11(F),12(F)
Flags: B-Blocking, D-Disabled, F-Forwarding, I-Listening, L-Learning

* EXOS-VM.6 # show stpd s0 ports
Port     Mode   State      Cost  Flags     Priority Port ID Designated Bridge
1      802.1D FORWARDING 200000 eDappw–B- 128      8001    80:00:0c:72:16:bd:8e:00
2      802.1D FORWARDING 200000 eDappw–B- 128      8002    80:00:0c:72:16:bd:8e:00
3      802.1D FORWARDING 200000 eDappw–B- 128      8003    80:00:0c:72:16:bd:8e:00
4      802.1D FORWARDING 200000 eDappw–B- 128      8004    80:00:0c:72:16:bd:8e:00
5      802.1D FORWARDING 200000 eDappw–B- 128      8005    80:00:0c:72:16:bd:8e:00
6      802.1D FORWARDING 200000 eDappw–B- 128      8006    80:00:0c:72:16:bd:8e:00
7      802.1D FORWARDING 200000 eDappw–B- 128      8007    80:00:0c:72:16:bd:8e:00
8      802.1D FORWARDING 200000 eDappw–B- 128      8008    80:00:0c:72:16:bd:8e:00
9      802.1D FORWARDING 200000 eDappw–B- 128      8009    80:00:0c:72:16:bd:8e:00
10     802.1D FORWARDING 200000 eDappw–B- 128      800a    80:00:0c:72:16:bd:8e:00
11     802.1D FORWARDING 200000 eDappw–B- 128      800b    80:00:0c:72:16:bd:8e:00
12     802.1D FORWARDING 200000 eDappw–B- 128      800c    80:00:0c:72:16:bd:8e:00

Total Ports: 12

————————- Flags: —————————-
1:                e=Enable, d=Disable
2: (Port role)    R=Root, D=Designated, A=Alternate, B=Backup, M=Master
3: (Config type)  b=broadcast, p=point-to-point, e=edge, a=auto
4: (Oper. type)   b=broadcast, p=point-to-point, e=edge
5:                p=proposing, a=agree
6: (partner mode) d = 802.1d, w = 802.1w, m = mstp
7:                i = edgeport inconsistency
8:                S = edgeport safe guard active
s = edgeport safe guard configured but inactive
8:                G = edgeport safe guard bpdu restrict active in 802.1w and mstp
g = edgeport safe guard bpdu restrict active in 802.1d
9:                B = Boundary, I = Internal
10:               r = restricted role, t = active role

* EXOS-VM.8 # show config stp detail
#
# Module stp configuration.
#
configure mstp region 0c7216bd8e00
configure mstp revision 3
configure mstp format 0
create stpd s0
configure stpd s0 delete vlan default ports all
configure stpd s0 mode mstp cist
configure stpd s0 forwarddelay 15
configure stpd s0 hellotime 2
configure stpd s0 maxage 20
configure stpd s0 max-hop-count 20
configure stpd s0 priority-mode dot1t
configure stpd s0 priority 32768
configure stpd s0 default-encapsulation dot1d
configure stpd s0 loop-protect event-window 180
configure stpd s0 loop-protect event-threshold 3
configure stpd s0 backup-root off
configure stpd s0 trap new-root on
configure stpd s0 trap topology-change off
configure stpd s0 trap topology-change edge-ports off
configure stpd s0 tx-hold-count 6
enable stpd s0 auto-bind vlan Default
enable stpd s0
configure stpd flush-method vlan-and-port
configure stpd bpdu-forwarding on
configure stpd multicast send-query on

After adding another EXOS switch with two inter-switch links between them forming a looped topology, the second port on the non-root bridge is BLOCKING as expected.

EXOS-VM.2 # show stpd s0 p
Port     Mode   State      Cost  Flags     Priority Port ID Designated Bridge
1      802.1D FORWARDING 200000 eRapam–B- 128      8001    80:00:0c:72:16:86:e7:00
2      802.1D BLOCKING   200000 eAapam–B- 128      8002    80:00:0c:72:16:86:e7:00