Dell N1548P Spanning Tree Bug? Or I'm Lost?

Question

Dear Community,

I think I don't need to write very much because, I guess that the following terminal output is quite illustrative. I can't understand why a RSTP enabled port in ALTN role has a mac-address-table with MAC addresses (should be 0 in DISCARDING state) and produces constant MAC_MOVE messages, which is misleading and also annoying!

Po1 is Root port. Forwarding State.

Po3 is Alternative port. Discarding State. Which is OK as designed.

Both trunk ports.

MAC addresses are flapping between Po1 and Po3 as if STP wasn't enabled or misconfigured.

<189> Jan 29 08:52:30 switch-1 FDB[dtlAddrTask]: fdb.c(651) 269141 %% NOTE MAC_MOVE: Mac XX:XX:XX:XX:XX:XX in VLAN: 30 is overwritten from entryType 1 to 1 and port Po1 to Po3

<189> Jan 29 08:53:40 switch-1 FDB[dtlAddrTask]: fdb.c(651) 269196 %% NOTE MAC_MOVE: Mac XX:XX:XX:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3

<189> Jan 29 08:53:43 switch-1 FDB[dtlAddrTask]: fdb.c(651) 269203 %% NOTE MAC_MOVE: Mac XX:XX:XX:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po3 to Po1

<189> Jan 29 08:53:52 switch-1 FDB[dtlAddrTask]: fdb.c(651) 269216 %% NOTE MAC_MOVE: Mac XX:XX:XX:XX:XX:XX in VLAN: 30 is overwritten from entryType 1 to 1 and port Po3 to Po1

<189> Jan 29 08:54:04 switch-1 FDB[dtlAddrTask]: fdb.c(651) 269226 %% NOTE MAC_MOVE: Mac XX:XX:XX:XX:XX:XX in VLAN: 30 is overwritten from entryType 1 to 1 and port Po3 to Po1

<189> Jan 29 08:54:07 switch-1 FDB[dtlAddrTask]: fdb.c(651) 269233 %% NOTE MAC_MOVE: Mac XX:XX:XX:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3

<189> Jan 29 08:54:10 switch-1 FDB[dtlAddrTask]: fdb.c(651) 269234 %% NOTE MAC_MOVE: Mac XX:XX:XX:XX:XX:XX in VLAN: 30 is overwritten from entryType 1 to 1 and port Po1 to Po3

<189> Jan 29 08:54:11 switch-1 FDB[dtlAddrTask]: fdb.c(651) 269237 %% NOTE MAC_MOVE: Mac XX:XX:XX:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po3 to Po1

<189> Jan 29 08:54:11 switch-1 FDB[dtlAddrTask]: fdb.c(651) 269238 %% NOTE MAC_MOVE: Mac XX:XX:XX:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po3 to Po1

switch#show spanning-tree

Spanning Tree            : Enabled
BPDU Flooding            : Disabled
Portfast BPDU Filtering  : Disabled
Mode                     : rstp
Portfast BPDU Guard      : Disabled
CST Regional Root        : 10:00:14:18:77:XX:XX:XX
Regional Root Path Cost  : 0
ROOT ID
              Priority        0
              Address         1418.77XX.XXXX
              Path Cost       1000
              Root Port       Po1
              Hello Time: 2s Max Age: 20s Forward Delay: 15s Transmit Hold Count: 6s
              Bridge Max Hops: 20
Bridge ID
              Priority        4096
              Address         1418.77XX.XXXX
              Hello Time: 2s Max Age: 20s Forward Delay: 15s Transmit Hold Count: 6s
Interfaces

Name      State    Prio.Nbr  Cost      Sts  Role  Restricted
--------- -------- --------- --------- ---- ----- ----------
Po1       Enabled  128.210   1000      FWD  Root  No
Po2       Enabled  128.211   0         DIS  Disb  No
Po3       Enabled  128.212   10000     DSC  Altn  No

switch#show spanning-tree port-channel 1

Port: Po1       Enabled
State: Forwarding                                Role: Root
Port ID: 128.210                                 Port Cost: 1000
Port Fast: No                                    Root Protection: No
Designated Bridge Priority: 4096                 Address: 1418.77XX.XXXX
Designated Port ID: 96.818                       Designated Path Cost: 0
CST Regional Root: 00:00:14:18:77:XX:XX:XX
Port fast status............................... False
Root Guard..................................... False
Loop Guard..................................... False
TCN Guard...................................... False
Auto Portfast.................................. False
BPDU Filter Mode............................... Disabled
Time Since Counters Last Cleared............... 2d18h10m4s
BPDUs: Sent: 6, Received: 119113

switch#show spanning-tree port-channel 3

Port: Po3       Enabled
State: Discarding                                Role: Alternate
Port ID: 128.212                                 Port Cost: 10000
Port Fast: No                                    Root Protection: No
Designated Bridge Priority: 4096                 Address: 1418.77XX.XXXX
Designated Port ID: 128.211                      Designated Path Cost: 333
CST Regional Root: 80:00:14:18:77:XX:XX:XX
Port fast status............................... False
Root Guard..................................... False
Loop Guard..................................... False
TCN Guard...................................... False
Auto Portfast.................................. False
BPDU Filter Mode............................... Disabled
Time Since Counters Last Cleared............... 2d18h10m6s
BPDUs: Sent: 4, Received: 119111

switch#show ver

Machine Description............... Dell EMC Networking Switch
System Model ID................... N1548P
Machine Type...................... Dell EMC Networking N1548P
Serial Number..................... XXXXXXXXXXXXXXXXXXXXXXX
Manufacturer...................... 0xbc00
Burned In MAC Address............. 1418.77XX.XXXX
System Object ID.................. 1.3.6.1.4.1.674.10895.3066
SOC Version....................... BCM56150_A0
HW Version........................ 2
CPLD Version...................... 16
Image File........................ N1500v6.6.3.6
Software Capability............... Stack Limit = 4, VLAN Limit = 512

unit active      backup      current-active next-active
---- ----------- ----------- -------------- --------------
1    6.6.3.6     6.5.3.3     6.6.3.6        6.6.3.6

Is this any kind of BUG or I am missing something here? On the other sides, no flapping occurs - also as expected -

The problem seems to be that instead of a true discarding state (Po3) the port seems to be receiving L2 frames and populating the mac table as normal.

Other switches are Dell too, but I believe the issue is right in this one, which has to discard frames is this switch in Discarding state, right?

Thanks a lot in advance!

DELL-Josh Cr · Answer

Hi echu2017,

That does seem strange. Can you try turning on loop guard on those ports and see if anything changes? The other thing to try would be turning off spanning-tree and re-enabling so it sets all of the port statuses again.

echu2017 · Answer

Hi @DELL-Josh Cr  !Thanks for your response! I've already tried loop guard.Regarding disabling and re enabling STP, is it equivalent to rebooting the switch?I ask this because, I've rebooted the switch multiple times without any behavioral difference. And as I am remotely connected, I am afraid of loosing access because of a loop while disabling STP.

echu2017 · Answer

I've forced a transition for Po3 from 'DSC' to 'FWD' by disabling Root port.Here is the full snip: Jan 29 15:54:47 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302240 %% NOTE MAC_MOVE: Mac 8A:F7:A7:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po3 to Po1 Jan 29 15:55:14 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302262 %% NOTE MAC_MOVE: Mac 32:57:35:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:15 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302263 %% NOTE MAC_MOVE: Mac E4:26:53:XX:XX:XX in VLAN: 20 is overwritten from entryType 1 to 1 and port Po3 to Po1 Jan 29 15:55:17 switch-1 TRAPMGR[trapTask]: traputil.c(721) 302265 %% NOTE Po3 is transitioned from the Forwarding state to the Blocking state in instance 0 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302268 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302269 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302270 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302271 %% NOTE MAC_MOVE: Mac 78:2B:CB:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302272 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302273 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302274 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302275 %% NOTE MAC_MOVE: Mac B0:83:FE:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302276 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302277 %% NOTE Spanning Tree Topology Change: 0, Unit: 1 Jan 29 15:55:21 switch-1 TRAPMGR[trapTask]: traputil.c(721) 302278 %% NOTE Po3 is transitioned from the Learning state to the Forwarding state in instance 0 Jan 29 15:56:19 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302354 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:19 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302355 %% NOTE Spanning Tree Topology Change: 0, Unit: 1 Jan 29 15:56:21 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302358 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:21 switch-1 TRAPMGR[trapTask]: traputil.c(721) 302359 %% NOTE Po3 is transitioned from the Forwarding state to the Blocking state in instance 0 Jan 29 15:56:23 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302362 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:25 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302370 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:25 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302371 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po3 Jan 29 15:56:27 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302374 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:27 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302375 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po3 Jan 29 15:56:29 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302376 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:29 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302377 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po3 Jan 29 15:56:30 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302379 %% NOTE MAC_MOVE: Mac C0:9F:E1:XX:XX:XX in VLAN: 4 is overwritten from entryType 1 to 1 and port Po1 to Po3 switch#show spanning-tree port-channel 1 Port: Po1 Enabled State: Forwarding Role: Root Port ID: 128.210 Port Cost: 1000 Port Fast: No Root Protection: No Designated Bridge Priority: 4096 Address: 1418.77XX.XXXX Designated Port ID: 96.818 Designated Path Cost: 0 CST Regional Root: 00:00:14:18:77:XX:XX:XX Port fast status............................... False Root Guard..................................... False Loop Guard..................................... False TCN Guard...................................... False Auto Portfast.................................. False BPDU Filter Mode............................... Disabled Time Since Counters Last Cleared............... 3d1h13m24s BPDUs: Sent: 8, Received: 131814 switch#show spanning-tree port-channel 3 Port: Po3 Enabled State: Discarding Role: Alternate Port ID: 128.212 Port Cost: 10000 Port Fast: No Root Protection: No Designated Bridge Priority: 4096 Address: 1418.77XX.XXXX Designated Port ID: 128.211 Designated Path Cost: 333 CST Regional Root: 80:00:14:18:77:XX:XX:XX Port fast status............................... False Root Guard..................................... False Loop Guard..................................... False TCN Guard...................................... False Auto Portfast.................................. False BPDU Filter Mode............................... Disabled Time Since Counters Last Cleared............... 3d1h13m24s BPDUs: Sent: 41, Received: 131785 switch#show mac address-table interface port-channel 3 Aging time is 300 Sec Vlan Mac Address Type Port -------- --------------------- ----------- --------------------- 1 0800.23XX.XXXX Dynamic Po3 1 1418.77XX.XXXX Dynamic Po3 4 3085.A9XX.XXXX Dynamic Po3 4 4413.D0XX.XXXX Dynamic Po3 4 C03F.D5XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3

DELL-Josh Cr · Answer

Are you able to break the port channel and see if it still happens as individual ports? Is this a new install or was it working on older firmware previously?

echu2017 · Answer

I've forced a transition from 'ALTN' to 'FWD' by disabling Root port.Here is the full snip: Jan 29 15:54:47 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302240 %% NOTE MAC_MOVE: Mac 8A:F7:A7:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po3 to Po1 Jan 29 15:55:14 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302262 %% NOTE MAC_MOVE: Mac 32:57:35:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:15 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302263 %% NOTE MAC_MOVE: Mac E4:26:53:XX:XX:XX in VLAN: 20 is overwritten from entryType 1 to 1 and port Po3 to Po1 Jan 29 15:55:17 switch-1 TRAPMGR[trapTask]: traputil.c(721) 302265 %% NOTE Po3 is transitioned from the Forwarding state to the Blocking state in instance 0 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302268 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302269 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302270 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302271 %% NOTE MAC_MOVE: Mac 78:2B:CB:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302272 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302273 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302274 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302275 %% NOTE MAC_MOVE: Mac B0:83:FE:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302276 %% NOTE MAC_MOVE: Mac D8:9E:F3:XX:XX:XX in VLAN: 1 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 15:55:21 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302277 %% NOTE Spanning Tree Topology Change: 0, Unit: 1 Jan 29 15:55:21 switch-1 TRAPMGR[trapTask]: traputil.c(721) 302278 %% NOTE Po3 is transitioned from the Learning state to the Forwarding state in instance 0 Jan 29 15:56:19 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302354 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:19 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302355 %% NOTE Spanning Tree Topology Change: 0, Unit: 1 Jan 29 15:56:21 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302358 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:21 switch-1 TRAPMGR[trapTask]: traputil.c(721) 302359 %% NOTE Po3 is transitioned from the Forwarding state to the Blocking state in instance 0 Jan 29 15:56:23 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302362 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:25 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302370 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:25 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302371 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po3 Jan 29 15:56:27 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302374 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:27 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302375 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po3 Jan 29 15:56:29 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302376 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 15:56:29 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 302377 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po3 Jan 29 15:56:30 switch-1 FDB[dtlAddrTask]: fdb.c(651) 302379 %% NOTE MAC_MOVE: Mac C0:9F:E1:XX:XX:XX in VLAN: 4 is overwritten from entryType 1 to 1 and port Po1 to Po3 switch#show spanning-tree port-channel 1 Port: Po1 Enabled State: Forwarding Role: Root Port ID: 128.210 Port Cost: 1000 Port Fast: No Root Protection: No Designated Bridge Priority: 4096 Address: 1418.77XX.XXXX Designated Port ID: 96.818 Designated Path Cost: 0 CST Regional Root: 00:00:14:18:77:XX:XX:XX Port fast status............................... False Root Guard..................................... False Loop Guard..................................... False TCN Guard...................................... False Auto Portfast.................................. False BPDU Filter Mode............................... Disabled Time Since Counters Last Cleared............... 3d1h13m24s BPDUs: Sent: 8, Received: 131814 switch#show spanning-tree port-channel 3 Port: Po3 Enabled State: Discarding Role: Alternate Port ID: 128.212 Port Cost: 10000 Port Fast: No Root Protection: No Designated Bridge Priority: 4096 Address: 1418.77XX.XXXX Designated Port ID: 128.211 Designated Path Cost: 333 CST Regional Root: 80:00:14:18:77:XX:XX:XX Port fast status............................... False Root Guard..................................... False Loop Guard..................................... False TCN Guard...................................... False Auto Portfast.................................. False BPDU Filter Mode............................... Disabled Time Since Counters Last Cleared............... 3d1h13m24s BPDUs: Sent: 41, Received: 131785 switch#show mac address-table interface port-channel 3 Aging time is 300 Sec Vlan Mac Address Type Port -------- --------------------- ----------- --------------------- 1 0800.23XX.XXXX Dynamic Po3 1 1418.77XX.XXXX Dynamic Po3 4 3085.A9XX.XXXX Dynamic Po3 4 4413.D0XX.XXXX Dynamic Po3 4 C03F.D5XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3

echu2017 · Answer

To summarize:1. Spanning-Tree mode is set to RSTP.2. Po3 had two members: Gi1/0/1 and Gi1/0/2 in LACP mode (channel-group 3 mode active).3. Bringing one member down, did not restore the expected RSTP behavior in Discarding State (i.e. MAC Address-table empty, no MAC_MOVE messages)4. Bringing the 'root port' of the switch connected to Po3 down, triggered the transition from Discarding to Forwarding (as expected). So at least this works as expected.5. Breaking down the port-channel as suggested by @DELL-Josh Cr and having a single port as an alternative uplink did restore the desired behavior of STP while in DSC state: Which is empty mac-address-table and NO MAC_MOVE messages (flapping hosts).

echu2017 · Answer

I'll get you by PM!Done, we now have both scenarios running! Jan 29 17:36:14 switch-1 TRAPMGR[trapTask]: traputil.c(721) 318044 %% NOTE Link Up: Gi1/0/1 Jan 29 17:36:15 switch-1 DOT3AD[dot3ad_core_lac]: dot3ad_db.c(959) 318046 %% INFO Interface Gi1/0/1 attached to ch3. Jan 29 17:36:15 switch-1 DOT3AD[dot3ad_core_lac]: dot3ad_lac.c(299) 318047 %% NOTE ch3 is up. Jan 29 17:36:15 switch-1 TRAPMGR[trapTask]: traputil.c(721) 318048 %% NOTE Po3 is transitioned from the Forwarding state to the Blocking state in instance 0 Jan 29 17:36:37 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 318058 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Gi1/0/2 Jan 29 17:36:37 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 318059 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po3 Jan 29 17:36:37 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 318060 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 17:36:39 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 318061 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Gi1/0/2 Jan 29 17:36:39 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 318062 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 17:36:39 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 318063 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po3 Jan 29 17:36:41 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 318066 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Gi1/0/2 Jan 29 17:36:41 switch-1 TRAPMGR[dot1s_task]: traputil.c(763) 318067 %% NOTE Spanning Tree Topology Change Received: MSTID: 0 Po1 Jan 29 17:36:48 switch-1 FDB[dtlAddrTask]: fdb.c(651) 318069 %% NOTE MAC_MOVE: Mac C0:9F:E1:XX:XX:XX in VLAN: 4 is overwritten from entryType 1 to 1 and port Po1 to Po3 switch#show spanning-tree Jan 29 17:37:05 switch-1 FDB[dtlAddrTask]: fdb.c(651) 318077 %% NOTE MAC_MOVE: Mac 94:27:90:XX:XX:XX in VLAN: 20 is overwritten from entryType 1 to 1 and port Po1 to Po3 Jan 29 17:37:05 switch-1 FDB[dtlAddrTask]: fdb.c(651) 318078 %% NOTE MAC_MOVE: Mac 94:27:90:XX:XX:XX in VLAN: 20 is overwritten from entryType 1 to 1 and port Po3 to Po1 Interfaces Name State Prio.Nbr Cost Sts Role Restricted --------- -------- --------- --------- ---- ----- ---------- Gi1/0/2 Enabled 128.2 20000 DSC Altn No Po3 Enabled 128.212 20000 DSC Altn No Jan 29 17:38:01 switch-1 FDB[dtlAddrTask]: fdb.c(651) 318126 %% NOTE MAC_MOVE: Mac 7C:89:56:XX:XX:XX in VLAN: 20 is overwritten from entryType 1 to 1 and port Po1 to Po3 switch#show mac address-table interface gi1/0/2 Aging time is 300 Sec Vlan Mac Address Type Port -------- --------------------- ----------- --------------------- Forwarding Database Empty. switch#show mac address-table interface po3 Aging time is 300 Sec Vlan Mac Address Type Port -------- --------------------- ----------- --------------------- 1 1418.77XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C09F.E1XX.XXXX Dynamic Po3 4 C85A.9FXX.XXXX Dynamic Po3 20 7C89.56XX.XXXX Dynamic Po3 switch#show interfaces port-channel Channel Ports Ch-Type Hash Type Min-links Local Prf Rx Util Tx Util ------- ----------------------------- -------- --------- --------- --------- --------- --------- Po3 Active: Gi1/0/1 Dynamic 5 1 Disabled 0 0

echu2017 · Answer

That absolutely restored the expected behavior ! Having a single port without any port-channel.

show spanning-tree

<...>
Interfaces

Name      State    Prio.Nbr  Cost      Sts  Role  Restricted
--------- -------- --------- --------- ---- ----- ----------
<...>
Gi1/0/2   Enabled  128.2     20000     DSC  Altn  No
<...>

show mac address-table interface gi1/0/2

Aging time is 300 Sec

Vlan     Mac Address           Type        Port
-------- --------------------- ----------- ---------------------

Forwarding Database Empty.

So we can say that this is a BUG in the interoperability between STP and Port-Channels??
Where should I report it?

DELL-Josh Cr · Answer

Try recreating the port channels and see if it breaks again or continues to work. If you can private message me the service tag I can have it escalated. Alternatively, phone support can do the escalation.

echu2017 · Answer

Hi @DELL-Josh Cr !! Did you received any updates on this???

DELL-Josh Cr · Answer

I have not heard anything new and I don’t see it in the most recent release. https://dell.to/3lVuAKJ I unfortunately, don’t have any exposure to the development process, so I don’t really have a good answer to tell you for when it will be fixed, just that I had it escalated so they are aware.

echu2017 · Answer

Thanks, I've checked latest release and it's not there. Would you mind to check with them if they at least could reproduce mi issue? Thanks!

Edictsystems · Answer

Is there an update to this? I am seeing an almost identical situation on some switches that have STP Discarding on a port-channel but still happens to be learning MAC address on that interface. All switches are at 7.6.1.21 currently.

Any help would be great. Thanks!

DELL-Charles R · Answer

Hello,   What switches are you using?   For N1500 Series - Firmware Version 6.8.1.4 is the latest Dell validated version https://dell.to/3wSao6f

Edictsystems · Answer

@DELL-Charles R​ These are N2000 series switches. It appears we are only 1 FW update behind, as 7.6.1.22 seems to be the latest. I looked through the release notes for that version and don't see any mention for fixes to RSTP and port-channel issues.

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