04-25-2018 02:58 PM - edited 03-08-2019 02:47 PM
Hi Guys,
I am little confused about the stp instance calculation.
Can you pls conform the number instances from the below outputs and how we are calculating it ?
UPE_CS01_LKO#show spanning-tree sum
UPE_CS01_LKO#show spanning-tree summary
Switch is in pvst mode
Root bridge for: VLAN0001, VLAN0011-VLAN0021, VLAN0025, VLAN0031-VLAN0033
VLAN0051-VLAN0052, VLAN0055, VLAN0061-VLAN0064, VLAN0066, VLAN0071
VLAN0101-VLAN0102, VLAN0275, VLAN0279, VLAN0286, VLAN0300-VLAN0301, VLAN031
VLAN0320-VLAN0321, VLAN0327, VLAN0358, VLAN0383
Extended system ID is enabled
Portfast Default is disabled
PortFast BPDU Guard Default is disabled
Portfast BPDU Filter Default is disabled
Loopguard Default is disabled
EtherChannel misconfig guard is enabled
UplinkFast is disabled
BackboneFast is disabled
Configured Pathcost method used is short
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
VLAN0001 0 0 0 9 9
VLAN0011 0 0 0 16 16
VLAN0012 0 0 0 3 3
VLAN0013 0 0 0 2 2
VLAN0014 0 0 0 6 6
VLAN0015 0 0 0 8 8
--More--
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
VLAN0016 0 0 0 2 2
VLAN0017 0 0 0 14 14
VLAN0018 0 0 0 3 3
VLAN0019 0 0 0 3 3
VLAN0020 0 0 0 2 2
VLAN0021 0 0 0 2 2
VLAN0025 0 0 0 4 4
VLAN0031 0 0 0 6 6
VLAN0030 0 0 0 4 4
VLAN0033 0 0 0 4 4
VLAN0051 0 0 0 4 4
VLAN0052 0 0 0 4 4
VLAN0055 0 0 0 8 8
VLAN0061 0 0 0 3 3
VLAN0062 0 0 0 3 3
VLAN0063 1 0 0 2 3
VLAN0064 0 0 0 3 3
VLAN0066 0 0 0 4 4
VLAN0071 0 0 0 2 2
VLAN0101 0 0 0 2 2
VLAN0102 0 0 0 2 2
VLAN0275 0 0 0 4 4
VLAN0279 0 0 0 2 2
--More--
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
VLAN0286 0 0 0 2 2
VLAN0300 0 0 0 4 4
VLAN0302 0 0 0 4 4
VLAN0315 0 0 0 5 5
VLAN0320 0 0 0 5 5
VLAN0321 0 0 0 4 4
VLAN0335 0 0 0 4 4
VLAN0427 0 0 0 4 4
VLAN0458 0 0 0 4 4
VLAN0483 0 0 0 2 2
---------------------- -------- --------- -------- ---------- ----------
39 vlans 1 0 0 169 170
It is calculated by the vlan number's or active STP ??
04-26-2018 03:01 AM
Hi
For evry vlan you add, cisco will by default, start an stp instance. You can disable stp per vlan. If you haven't done that, you have 39 stp instances.
There are often limits on how many stp instances a switch can handle. So if you enabla more vlan than the switch can handle stp for, there will be vlan that doesn' run stp. Different switch models can have different limits.
/Mikael
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