Bridge restarts on adding an interface list to members

[freaknils]

Hello everyone,

we are currently using several of your switches as part of our backbone infrastructure.

To simplify configuration, we are making use of interface lists (e.g., for applying common policies, VLAN configurations). While this approach works well in general, we have got the problem, that while adding an interface list to the bridge with MLAG (even without interfaces in it) the bridge restarts.
See log (I have added the list "Uplink_ELP"):

# 2026-04-13 08:43:44 by RouterOS 7.20.7
# software id = IWS4-UGS7
#
2026-04-13 08:34:02 system,info interface list added by tcp-msg(winbox):admin@10.49.1.26 (*2000015 = /interface list add exclude="" include="" name=Uplink_ELP)
2026-04-13 08:34:34 bridge,warning "bridge1" peer disconnected 
2026-04-13 08:34:34 bridge,warning "bridge1" peer link down 
2026-04-13 08:34:34 bridge,info "bridge1" peer link up 
2026-04-13 08:34:36 system,info bridge port added by tcp-msg(winbox):admin@10.49.1.26 (*2D = /interface bridge port add auto-isolate=no bpdu-guard=no bridge=bridge1 broadcast-flood=yes disabled=no edge=auto fast-leave=no frame-types=admit-all horizon=none hw=yes ingress-filtering=yes interface=Uplink_ELP learn=auto multicast-router=temporary-query mvrp-applicant-state=normal-participant mvrp-registrar-state=normal point-to-point=auto priority=0x80 pvid=1 restricted-role=yes restricted-tcn=no tag-stacking=no trusted=no unknown-multicast-flood=yes unknown-unicast-flood=yes)
2026-04-13 08:34:36 bridge,info hardware offloading deactivated on bridge "bridge1" ports: bonding20,bonding30
2026-04-13 08:34:36 bridge,info "bridge1" peer link up
2026-04-13 08:34:36 bridge,info hardware offloading activated on bridge "bridge1" ports: qsfpplus2-1,bonding20,qsfpplus1-1,bonding30
2026-04-13 08:34:36 bridge,info "bridge1" peer connected
2026-04-13 08:34:36 bridge,info "bridge1" peer becomes primary F4:1E:57:0D:6A:5E
2026-04-13 08:34:53 bridge,warning no buffer space available for fdb notify
2026-04-13 08:35:19 system,info bridge port changed by tcp-msg(winbox):admin@10.49.1.26 (/interface bridge port set *2D auto-isolate=no bpdu-guard=no bridge=bridge1 broadcast-flood=yes disabled=no edge=auto fast-leave=no frame-types=admit-only-vlan-tagged horizon=none hw=yes ingress-filtering=yes interface=Uplink_ELP learn=auto multicast-router=temporary-query mvrp-applicant-state=normal-participant mvrp-registrar-state=normal point-to-point=auto priority=0x80 pvid=1 restricted-role=yes restricted-tcn=no tag-stacking=no trusted=no unknown-multicast-flood=yes unknown-unicast-flood=yes)
2026-04-13 08:35:19 bridge,info hardware offloading deactivated on bridge "bridge1" ports: bonding30,bonding20
2026-04-13 08:35:19 bridge,info "bridge1" peer link up
2026-04-13 08:35:20 bridge,info hardware offloading activated on bridge "bridge1" ports: bonding30,qsfpplus1-1,qsfpplus2-1,bonding20
2026-04-13 08:35:20 bridge,info "bridge1" peer connected
2026-04-13 08:35:20 bridge,info "bridge1" peer becomes primary F4:1E:57:0D:6A:5E
2026-04-13 08:35:42 bridge,warning "bridge1" peer disconnected
2026-04-13 08:35:42 bridge,warning "bridge1" peer link down
2026-04-13 08:35:42 bridge,info "bridge1" peer link up
2026-04-13 08:35:43 bridge,info "bridge1" peer connected
2026-04-13 08:35:43 bridge,info "bridge1" peer becomes primary F4:1E:57:0D:6A:5E
2026-04-13 08:37:04 system,info item changed by tcp-msg(winbox):admin@10.49.1.26 (/interface bridge vlan set "" bridge=bridge1 disabled=no mvrp-forbidden="" tagged=Uplink,Uplink_Admin,sfp-sfpplus1,Uplink_ohne_BPDU,Uplink_ELP untagged="" vlan-ids=1010)
2026-04-13 08:37:15 system,info item changed by tcp-msg(winbox):admin@10.49.1.26 (/interface bridge vlan set "" bridge=bridge1 disabled=no mvrp-forbidden="" tagged=Uplink,Uplink_Admin,sfp-sfpplus1,Uplink_ohne_BPDU,Uplink_ELP untagged="" vlan-ids=1020)

Used config:

[admin@swlan-1.12-01] > /interface/list/export 
# 2026-04-13 08:54:57 by RouterOS 7.20.7
# software id = IWS4-UGS7
#
# model = CRS326-24S+2Q+
# serial number = HGS0ADQ5BRY
/interface list
add name=Management
add name=Uplink
add name=Uplink_Admin
add name=Uplink_ToR
add name=Uplink_ohne_BPDU
add name=Uplink_ELP
/interface list member
add interface=ether1 list=Management
add interface=qsfpplus1-1 list=Uplink
add interface=sfp-sfpplus9 list=Uplink_Admin
add interface=sfp-sfpplus10 list=Uplink_Admin
add interface=sfp-sfpplus11 list=Uplink_Admin
add interface=qsfpplus2-1 list=Uplink
add interface=bonding20 list=Uplink_ohne_BPDU
add interface=bonding30 list=Uplink_ohne_BPDU
/interface bridge
add name=bridge1 priority=0 vlan-filtering=yes
/interface bridge mlag
set bridge=bridge1 peer-port=qsfpplus2-1 priority=64
/interface bridge port
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus4 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus5 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus6 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus7 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus8 restricted-role=yes
add bridge=bridge1 interface=sfp-sfpplus9 restricted-role=yes
add bridge=bridge1 interface=sfp-sfpplus10 restricted-role=yes
add bridge=bridge1 interface=sfp-sfpplus11 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus13 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus14 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus15 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus16 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus17 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus18 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus19 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus20 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus21 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus22 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=sfp-sfpplus23 restricted-role=yes
add bridge=bridge1 interface=sfp-sfpplus1 restricted-role=yes
add bpdu-guard=yes bridge=bridge1 interface=bonding1 restricted-role=yes
add bridge=bridge1 frame-types=admit-only-vlan-tagged interface=Uplink trusted=yes
add bridge=bridge1 frame-types=admit-only-vlan-tagged interface=Uplink_ToR restricted-role=yes
add bpdu-guard=yes bridge=bridge1 frame-types=admit-only-vlan-tagged interface=Uplink_ohne_BPDU restricted-role=yes trusted=yes
add bridge=bridge1 frame-types=admit-only-vlan-tagged interface=Uplink_ELP restricted-role=yes
/interface bridge vlan
add bridge=bridge1 tagged=Uplink,Uplink_Admin,Uplink_ToR,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=1000
add bridge=bridge1 tagged=Uplink,Uplink_Admin,sfp-sfpplus1,Uplink_ohne_BPDU,Uplink_ELP vlan-ids=1010
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=1011
add bridge=bridge1 tagged=Uplink,Uplink_Admin,sfp-sfpplus1,Uplink_ohne_BPDU,Uplink_ELP vlan-ids=1020
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=1040
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=1050
add bridge=bridge1 tagged=Uplink,Uplink_Admin,Uplink_ToR,sfp-sfpplus1,bonding1,Uplink_ohne_BPDU vlan-ids=1150
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=1174
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=2240
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=2280
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=2288
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=2305
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=2313
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=1021
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=1022
add bridge=bridge1 tagged=Uplink,sfp-sfpplus1,Uplink_ohne_BPDU vlan-ids=2702
add bridge=*2D tagged=bonding20 vlan-ids=1010

Why does the bridge restart and why is the hardware offloading stopped for a short period of time?

We use stable branch!

Thanks!

[jaclaz]

@freaknils

add bridge=*2D

Very likely not related, stiill check point #21 here:

GP & CSA (Good Practice and Common Sense Advice) for Mikrotik devices

Preamble and disclaimer: The following is a numbered list of what is usually considered good practice or common sense advice when choosing, using, setting up or maintaining a Mikrotik router. It is my personal take on the matter, and in no way approved, endorsed or recommended, officially or unofficially, by Mikrotik or their partners or by anyone else. In other words you are perfectly free to ignore its contents, though they represent (IMHO) a sort of (useful) check list for people starting …

[freaknils]

Thanks, this was orphaned entry. But I think, that's not the cause of my problem

[jaclaz]

Well, yes and no.

It surely accounts for 27 out of 105 seconds of your cycle, i.e. roughly between 1/4 and 1/3.

As I see it, the operation that take the more time (21-27 seconds) is:

 bridge,info "bridge1" peer becomes primary F4:1E:57:0D:6A:5E

and you are executing it three times (and 1 is related to the *2D).

The other operation that takes time is:

bridge,warning no buffer space available for fdb notify

Note	Time (seconds)	Log Entry	Column 4
		# 2026-04-13 08:43:44 by RouterOS 7.20.7
		# software id = IWS4-UGS7
		#
irrelevant	0	2026-04-13 08:34:02 system,info interface list added by tcp-msg(winbox):admin@10.49.1.26 (*2000015 = /interface list add exclude= include= name=Uplink_ELP)
Within 1 second	1	2026-04-13 08:34:34 bridge,warning bridge1 peer disconnected
		2026-04-13 08:34:34 bridge,warning bridge1 peer link down
		2026-04-13 08:34:34 bridge,info bridge1 peer link up
Timeout	2
Within 1 second		2026-04-13 08:34:36 system,info bridge port added by tcp-msg(winbox):admin@10.49.1.26 (*2D = /interface bridge port add auto-isolate=no bpdu-guard=no bridge=bridge1 broadcast-flood=yes disabled=no edge=auto fast-leave=no frame-types=admit-all horizon=none hw=yes ingress-filtering=yes interface=Uplink_ELP learn=auto multicast-router=temporary-query mvrp-applicant-state=normal-participant mvrp-registrar-state=normal point-to-point=auto priority=0x80 pvid=1 restricted-role=yes restricted-tcn=no tag-stacking=no trusted=no unknown-multicast-flood=yes unknown-unicast-flood=yes)
		2026-04-13 08:34:36 bridge,info hardware offloading deactivated on bridge bridge1 ports: bonding20,bonding30
		2026-04-13 08:34:36 bridge,info bridge1 peer link up
		2026-04-13 08:34:36 bridge,info hardware offloading activated on bridge bridge1 ports: qsfpplus2-1,bonding20,qsfpplus1-1,bonding30
		2026-04-13 08:34:36 bridge,info bridge1 peer connected
	1	2026-04-13 08:34:36 bridge,info bridge1 peer becomes primary F4:1E:57:0D:6A:5E
Time for execution	27
		2026-04-13 08:34:53 bridge,warning no buffer space available for fdb notify
Time for execution	26
Within 1 second	1	2026-04-13 08:35:19 system,info bridge port changed by tcp-msg(winbox):admin@10.49.1.26 (/interface bridge port set *2D auto-isolate=no bpdu-guard=no bridge=bridge1 broadcast-flood=yes disabled=no edge=auto fast-leave=no frame-types=admit-only-vlan-tagged horizon=none hw=yes ingress-filtering=yes interface=Uplink_ELP learn=auto multicast-router=temporary-query mvrp-applicant-state=normal-participant mvrp-registrar-state=normal point-to-point=auto priority=0x80 pvid=1 restricted-role=yes restricted-tcn=no tag-stacking=no trusted=no unknown-multicast-flood=yes unknown-unicast-flood=yes)
		2026-04-13 08:35:19 bridge,info hardware offloading deactivated on bridge bridge1 ports: bonding30,bonding20
		2026-04-13 08:35:19 bridge,info bridge1 peer link up
Timeout	1
Within 1 second	1	2026-04-13 08:35:20 bridge,info hardware offloading activated on bridge bridge1 ports: bonding30,qsfpplus1-1,qsfpplus2-1,bonding20
		2026-04-13 08:35:20 bridge,info bridge1 peer connected
		2026-04-13 08:35:20 bridge,info bridge1 peer becomes primary F4:1E:57:0D:6A:5E
Time for execution	22
Within 1 second	1	2026-04-13 08:35:42 bridge,warning bridge1 peer disconnected
		2026-04-13 08:35:42 bridge,warning bridge1 peer link down
		2026-04-13 08:35:42 bridge,info bridge1 peer link up
Timeout	1
		2026-04-13 08:35:43 bridge,info bridge1 peer connected
		2026-04-13 08:35:43 bridge,info bridge1 peer becomes primary F4:1E:57:0D:6A:5E
Time for execution	21
irrelevant	0	2026-04-13 08:37:04 system,info item changed by tcp-msg(winbox):admin@10.49.1.26 (/interface bridge vlan set bridge=bridge1 disabled=no mvrp-forbidden= tagged=Uplink,Uplink_Admin,sfp-sfpplus1,Uplink_ohne_BPDU,Uplink_ELP untagged= vlan-ids=1010)
TOTAL	105

Very likely the restart of the bridge cannot be avoided, turning off/on hardware offloading takes only 1 second or less, so the only thing I believe you can try is to have only one disable/enable of the bridge.

Maybe you can disable the bridge manually BEFORE updating it and then re-enable it AFTER you have changed the settings?

No idea how the "buffer space available for fdb notify" could be avoided.

[freaknils]

Hi thanks for your reply,

I think the

bridge,info "bridge1" peer becomes primary F4:1E:57:0D:6A:5E

comes from my MLAG setup. But why does RouterOS turn off the hardware offloading?

In my eyes this is not an expected behaviour.

Additionaly: When I add an interface to a interface list, which will add this interface to the bridge with no big trouble.

Maybe the buffer space error is my cause. Disabling the bridge before changings is not possible, because the switch is in main production.