Description

The "STP handler: Stp index=10, op=change, state=Forwarding, Topo change generation=0" message is reported into the system message file if an Ethernet interface on the device flaps or STP configuration changes. This article documents that this is an expected behavior and these STP messages can be ignored.

Symptoms

The following "STP Handler" and "STP Change" messages appear in the message file when an Ethernet link flaps or STP configuration changes:

Show log messages:

Mar 24 18:58:34 Mx480 rpd[2924]: EVENT <UpDown> ge-3/0/8 index 173 <Up Broadcast Multicast> address #0 2c.6b.f5.4c.23.e6
Mar 24 18:58:34 Mx480 rpd[2924]: STP handler: Stp index=10, op=change, state=Forwarding, Topo change generation=0 
Mar 24 18:58:34 Mx480 rpd[2924]: *STP Change*, notify to other modules

Solution

This informational message comes from the rpd (routing process) STP message handler, which is responsible for decoding received rtsock messages from another user daemon and notifying corresponding routines:

Mar 24 18:58:34 Mx480 rpd[2924]: EVENT <UpDown> ge-3/0/8 index 173 <Up Broadcast Multicast> address #0 2c.6b.f5.4c.23.e6
Mar 24 18:58:34 Mx480 rpd[2924]: STP handler: Stp index=10, op=change, state=Forwarding, Topo change generation=0 ----->decoded
Mar 24 18:58:34 Mx480 rpd[2924]: *STP Change*, notify to other modules ----->notifying

These messages are information and expected and can be ignored if:

  1. The device is not running spanning tree and the messages appear only when an interface flaps.
    or
  2. STP configuration changes on the device.
Note:   These messages are reported only if the system syslog is set for any any.

The following two tests confirm the above two points.

TEST 1:

This lab test shows that when an interface which has no STP configuration is disabled/enabled, the STP messages can be seen: 
lab@Mx480# run show configuration interfaces ge-3/0/8
Mar 24 18:57:24

[edit]
lab@Mx480# run show interfaces terse ge-3/0/8
Mar 24 18:57:40
Interface Admin Link Proto Local Remote
ge-3/0/8  up    up

[edit]
lab@Mx480# set interfaces ge-3/0/8 disable
Mar 24 18:57:55

[edit]
lab@Mx480# commit
Mar 24 18:57:57
commit complete

[edit]
lab@Mx480# run show interfaces terse ge-3/0/8
Mar 24 18:58:04
Interface Admin Link Proto Local Remote
ge-3/0/8  down  down

[edit]
lab@Mx480# run show configuration interfaces ge-3/0/8
Mar 24 18:58:11
disable;

[edit]
lab@Mx480# delete interfaces ge-3/0/8 disable
Mar 24 18:58:25

[edit]
lab@Mx480# commit
Mar 24 18:58:28
commit complete

[edit]
lab@Mx480# run show interfaces terse ge-3/0/8
Mar 24 18:58:49
Interface Admin Link Proto Local Remote
ge-3/0/8  up    up
[edit]
lab@Mx480# run show log messages
Mar 24 18:59:07
Mar 24 18:58:34 Mx480 rpd[2924]: EVENT <UpDown> ge-3/0/8 index 173 <Up Broadcast Multicast> address #0 2c.6b.f5.4c.23.e6
Mar 24 18:58:34 Mx480 rpd[2924]: STP handler: Stp index=10, op=change, state=Forwarding, Topo change generation=0
Mar 24 18:58:34 Mx480 rpd[2924]: *STP Change*, notify to other modules
Mar 24 18:58:34 Mx480 mib2d[2990]: SNMP_TRAP_LINK_UP: ifIndex 685, ifAdminStatus up(1), ifOperStatus up(1), ifName ge-3/0/8

Below is the system syslog configuration on the device: 
lab@Mx480# run show configuration system syslog
Mar 24 18:59:28
user * {
    any emergency;
}
file interactive-commands {
    interactive-commands any;
}
file messages {
    any any;
}

TEST 2:

New STP configuration on the device triggers these messages: 

lab# run show configuration protocols mstp
Mar 31 10:17:19
interface ge-3/0/2;
msti 1 {
    vlan 100;
}
________________________________________________

Adding new msti :  <<<<<<<<<<<< Adding new STP configuration

lab# set protocols mstp msti 2 vlan 200
Mar 31 10:17:52

[edit]
lab# commit
Mar 31 10:17:56
commit complete
_________________________________________________

lab# run show log messages
Mar 31 10:18:12

Mar 31 10:18:00 rpd[1727]: STP handler: IFD =NULL, op=change, state=Forwarding, Topo change generation=0
Mar 31 10:18:00 rpd[1727]: *STP Change*, notify to other modules