All infra losing connectivity along time

[plavielle]

Hi, experts.

Can someone can explain me what phenomenom can block my entire network minutes after minutes, and after 1.5 hour, all goes well.

No infos in log (normal or flash). SPT disable, but i'm pretty sure i've no loop (pretty).

Materials : sg250-26 et 50 sg350 10 sfp firmware 2.5.8.12

[MHM Cisco World · Accepted solution]

Log work side by side with STP, if you disable STP how control plane is detect LOOP and Log message appear?
the LOOP is happen in data plane and there is flood of broadcast/multicast in network

just show any interface and see the broadcast/multicast counter you will see number is increase not by 10 but at least by 100.

[plavielle]

Okay.

But it's difficult when 150 persons call you "you know that internet doesnt work ???"

I'm in the process to reconfigure all my switch with STP enable and firmware 2.5.8.12 (not sure 2.5.8.15 the one i have actually is stable).

Thanks for your time and your help.

[MHM Cisco World]

Yes STP is mandatory for L2 LOOP prevent.

[plavielle]

on SG300 (my root stp) do i have to setup interface "root guard" and "edge port" ???

[MHM Cisco World]

edge port like port fast help only when connect host to SW to reduce the FWD time for port, 
so edge port is config only on port connect to host and for more secure config BPDU guard on edge port.
root guard must config in right port 
https://afrozahmad.com/blog/spanning-tree-guard-root/

[plavielle]

if i read interface statistics multicast grow up to 100k per seconds. Normal or not ????

[MHM Cisco World]

Not normal.

Check stp.