Switching

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

I'd go with what Chris is saying.    Check which ports are ROOT against the two devices....

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

The root on these switches and all the switches at each school site is the core fiber switch at the site.  The fiber switch has a much better priority than any other switch.  Many of the sites have few enough  IDFs that each switch is a home run to the fiber switch. Of the two switches in this topic, one hits a primary switch in the IDF and one is the only switch in the rack.  I will have to check to see if the same mac addr is the root bridge for all the switches at a site. I suspect it is.  

I'd go with what Chris is saying.    Check which ports are ROOT against the two devices....

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

Would be interested to know if the logs can shed more light. 

The root on these switches and all the switches at each school site is the core fiber switch at the site.  The fiber switch has a much better priority than any other switch.  Many of the sites have few enough  IDFs that each switch is a home run to the fiber switch. Of the two switches in this topic, one hits a primary switch in the IDF and one is the only switch in the rack.  I will have to check to see if the same mac addr is the root bridge for all the switches at a site. I suspect it is.  

I'd go with what Chris is saying.    Check which ports are ROOT against the two devices....

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

So in your problem statement, you say you do see topo changes.....  and we are assuming from the wording that there is only 1 uplink to the "fiber" switch.

This tells me that there could not be any loops so if your using spanning tree, on all vlans, and the primary switch has a lowest priority,(assuming there is a primary switch at each school), then there is something else that is triggering topo changes..  You also mention losing connection to Mist....the could trigger a topo change if your internet connection is somehowe using STP as well..... 

I am also assuming each school install is by itself, and not connected back to  a central site... if all locations are going back to a central site, then that primary needs to be root, and ALL other devices have a higher priority to keep them pointed to ONE location.     

Can you provide a model of one of the problem locations?  and/or a snippet of the configuration, especially protocols and vlan configs....

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

Here is a sparse definition of the LCBM syslog:

The syslog message "LBCM-L2,brcm_ifl_l2_init()" is related to the initialization of Layer 2 interfaces on devices using Broadcom chipsets. This message typically appears in the context of control plane operations and does not impact the forwarding plane, meaning transit traffic is not affected.

I would think that if the logical i/f (hence the ifl_L2 in the syslog) had an issue, it could logically shut down or restarted at the chip level which would trigger a topo change as stp is extremely fast at any comms issues between switches....

I would prob compare hardware against a known good 2300 vs. the one in question.... or replace the sfp's between primary and idf.   Ive had this issue before and sfp was at fault even though it runs 99% of the time.....

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

In the case of the switch named RV I swapped out a DAC cable for a new SM fiber and a pair of SFPs.  This switch is daisy-chained to a primary switch in the IDF rack. This did not resolve the issue. The switch named SR has a single-mode fiber home run to the core switch. I haven't swapped anything out on this one , yet. 

What makes me pause is these two switches have nothing plugged into them, in the case of the RV switch and only three devices in the case of the SR switch and yet their logs get filled in 2 days, where as other switches I took a look at had about 7 days of log and did not have the load of messages I posted above. 

Here is a sparse definition of the LCBM syslog:

The syslog message "LBCM-L2,brcm_ifl_l2_init()" is related to the initialization of Layer 2 interfaces on devices using Broadcom chipsets. This message typically appears in the context of control plane operations and does not impact the forwarding plane, meaning transit traffic is not affected.

I would think that if the logical i/f (hence the ifl_L2 in the syslog) had an issue, it could logically shut down or restarted at the chip level which would trigger a topo change as stp is extremely fast at any comms issues between switches....

I would prob compare hardware against a known good 2300 vs. the one in question.... or replace the sfp's between primary and idf.   Ive had this issue before and sfp was at fault even though it runs 99% of the time.....

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?

A head scratcher for sure......

I  would compare the entire config of those two against a known switch to not have these issues....

the rv switch appears to have auto-snapshot enabled, and may be doing it too often from the syslog msg....you can safely remove it if it is there...

Also, make sure NTP associations are working.

compare JunosOS and firmware versions if ya havn't already done so....

Are you using RTSP, or VSTP ?   

What type of devices are on the SR?

You can put those as an "edge" device to mitigate any bpdu/stp traffic....     

In the case of the switch named RV I swapped out a DAC cable for a new SM fiber and a pair of SFPs.  This switch is daisy-chained to a primary switch in the IDF rack. This did not resolve the issue. The switch named SR has a single-mode fiber home run to the core switch. I haven't swapped anything out on this one , yet. 

What makes me pause is these two switches have nothing plugged into them, in the case of the RV switch and only three devices in the case of the SR switch and yet their logs get filled in 2 days, where as other switches I took a look at had about 7 days of log and did not have the load of messages I posted above. 

Here is a sparse definition of the LCBM syslog:

The syslog message "LBCM-L2,brcm_ifl_l2_init()" is related to the initialization of Layer 2 interfaces on devices using Broadcom chipsets. This message typically appears in the context of control plane operations and does not impact the forwarding plane, meaning transit traffic is not affected.

I would think that if the logical i/f (hence the ifl_L2 in the syslog) had an issue, it could logically shut down or restarted at the chip level which would trigger a topo change as stp is extremely fast at any comms issues between switches....

I would prob compare hardware against a known good 2300 vs. the one in question.... or replace the sfp's between primary and idf.   Ive had this issue before and sfp was at fault even though it runs 99% of the time.....

I have two EX2300 switches doing the same thing at two different school sites. They lose connection to the Miast dashboard, but I can connect via ssh with MobaXterm. I checked optic power on one with a fiber cable and it's fine. I checked for any errors on the port and there were none. Not even drops. The other switch has a DAC cable to the primary switch in the rack and also does not show any errors on the port.  I do see topo changes generated on the uplink port on both switches. I tested to see if they were both connecting with port 443 as a system connection and they were. 

Other than scheduling a " have you tried turning it off and on again " switch reboot, I can't think of a next thing to check.  Any suggestions?