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Dynamic LACP issue on AOS-S

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  • 1.  Dynamic LACP issue on AOS-S

    Posted Nov 19, 2023 08:43 AM

    I've got two 2530-8G-PoE+ in a lab environment running YA.16.11.0014, and I'm looking into dynamic LACP functionality and MVRP.

    I've noticed that the dynamic Dyn interface is only created when there are two or more interfaces up between the switches.

    If I only connect one interface, an LACP peering is negotiated, but no Dyn dynamic interface is generated.

    This behaviour is of concern, as MVRP is enabled by default on Dyn interfaces (if enabled globally), but seemingly not on single-link dynamic LACP interfaces.

    If a customer uses MVRP, then a solution using dynamic LACP will not operate correctly in many link-failure scenarios.  

    Does anyone know:

    • Is this standard behaviour on all AOS-S platforms?
    • Can AOS-S be configured to generate the Dyn interface when an aggregate only contains 1 link?

    Regards,

    Pete.

    Example:

    I have a two links (port 9 & port 10) between two switches (Switch-004 and Switch-005) , both interfaces have "lacp active" configured on the interface.

    Switch-004# show run int 9-10

    Running configuration:

    interface 9
       lacp active
       untagged vlan 1
       exit
    interface 10
       lacp active
       untagged vlan 1
       exit

    Switch-005# show run int 9-10

    Running configuration:

    interface 9
       lacp active
       untagged vlan 1
       exit
    interface 10
       lacp active
       untagged vlan 1
       exit

    Step #1

    I connect port 10 only:

    Switch-004#
    I 11/19/23 12:55:45 00435 ports: port 10 is Blocked by LACP
    I 11/19/23 12:55:45 00435 ports: port 10 is Blocked by STP
    I 11/19/23 12:55:45 00839 stp: CST Root changed from 32768: (this device) to
                32768: 9cb654-2cfa70
    I 11/19/23 12:55:45 00076 ports: port 10 is now on-line
    I 11/19/23 12:55:45 00001 vlan: DEFAULT_VLAN virtual LAN enabled

    Switch-004#
    Switch-004# show lacp

                                        LACP

               LACP      Trunk     Port                LACP      Admin   Oper
       Port    Enabled   Group     Status    Partner   Status    Key     Key
       -----   -------   -------   -------   -------   -------   ------  ------
       9       Active    9         Down      No        Success   0       0
       10      Active    10        Up        Yes       Success   0       0

    Switch-004(eth-9)# show mvrp config

     Configuration and Status - MVRP

     Global MVRP status : Enabled

     Port     Status   Periodic Registration Join  Leave    LeaveAll Periodic
                       Timer    Type         Time  Timer    Timer    Timer
     -------  -------- -------- ------------ ----  -------- -------- --------
     1        Disabled Enabled  Normal       20    300      1000     100
     2        Disabled Enabled  Normal       20    300      1000     100
     3        Disabled Enabled  Normal       20    300      1000     100
     4        Disabled Enabled  Normal       20    300      1000     100
     5        Disabled Enabled  Normal       20    300      1000     100
     6        Disabled Enabled  Normal       20    300      1000     100
     7        Disabled Enabled  Normal       20    300      1000     100
     8        Disabled Enabled  Normal       20    300      1000     100
     9        Disabled Enabled  Normal       20    300      1000     100
     10       Disabled Enabled  Normal       20    300      1000     100

    Note that MVRP globally enabled, but is not functional on port 10.

    Step #2

    I now connect port 9:

    I 11/19/23 13:05:54 00435 ports: port 9 is Blocked by LACP
    I 11/19/23 13:05:55 00435 ports: port 10 is Blocked by LACP
    I 11/19/23 13:05:55 00839 stp: CST Root changed from 32768: 9cb654-2cfa70 to
                32768: (this device)
    I 11/19/23 13:05:55 00397 lacp: Port 10 is moved to trunk Dyn1
    I 11/19/23 13:05:55 00002 vlan: DEFAULT_VLAN virtual LAN disabled
    I 11/19/23 13:05:55 00397 lacp: Port 9 is moved to trunk Dyn1
    I 11/19/23 13:05:55 00078 ports: trunk Dyn1 is now active
    I 11/19/23 13:05:55 00435 ports: port 9 is Blocked by STP
    I 11/19/23 13:05:56 00839 stp: CST Root changed from 32768: (this device) to
                32768: 9cb654-2cfa70
    I 11/19/23 13:05:56 00076 ports: port 9 in Dyn1 is now on-line
    I 11/19/23 13:05:56 00001 vlan: DEFAULT_VLAN virtual LAN enabled
    I 11/19/23 13:06:23 00435 ports: port 10 is Blocked by STP
    I 11/19/23 13:06:23 00076 ports: port 10 in Dyn1 is now on-line
    Switch-004# show lacp

                                        LACP

               LACP      Trunk     Port                LACP      Admin   Oper
       Port    Enabled   Group     Status    Partner   Status    Key     Key
       -----   -------   -------   -------   -------   -------   ------  ------
       9       Active    Dyn1      Up        Yes       Success   0       0
       10      Active    Dyn1      Up        Yes       Success   0       0

    Switch-004(eth-9)# show mvrp config

     Configuration and Status - MVRP

     Global MVRP status : Enabled

     Port     Status   Periodic Registration Join  Leave    LeaveAll Periodic
                       Timer    Type         Time  Timer    Timer    Timer
     -------  -------- -------- ------------ ----  -------- -------- --------
     1        Disabled Enabled  Normal       20    300      1000     100
     2        Disabled Enabled  Normal       20    300      1000     100
     3        Disabled Enabled  Normal       20    300      1000     100
     4        Disabled Enabled  Normal       20    300      1000     100
     5        Disabled Enabled  Normal       20    300      1000     100
     6        Disabled Enabled  Normal       20    300      1000     100
     7        Disabled Enabled  Normal       20    300      1000     100
     8        Disabled Enabled  Normal       20    300      1000     100
     Dyn1     Enabled  Enabled  Normal       20    300      1000     100

    Note that MVRP is now functional on Dyn1.

    Step #3

    I now disconnect port 9:

    I 11/19/23 13:32:31 00077 ports: port 9 in Dyn1 is now off-line
    I 11/19/23 13:33:01 00398 lacp: Port 9 is removed from trunk Dyn1

    Switch-004# show lacp

                                        LACP

               LACP      Trunk     Port                LACP      Admin   Oper
       Port    Enabled   Group     Status    Partner   Status    Key     Key
       -----   -------   -------   -------   -------   -------   ------  ------
       9       Active    9         Down      No        Success   0       0
       10      Active    Dyn1      Up        Yes       Success   0       0


    Switch-004# show mvrp config

     Configuration and Status - MVRP

     Global MVRP status : Enabled

     Port     Status   Periodic Registration Join  Leave    LeaveAll Periodic
                       Timer    Type         Time  Timer    Timer    Timer
     -------  -------- -------- ------------ ----  -------- -------- --------
     1        Disabled Enabled  Normal       20    300      1000     100
     2        Disabled Enabled  Normal       20    300      1000     100
     3        Disabled Enabled  Normal       20    300      1000     100
     4        Disabled Enabled  Normal       20    300      1000     100
     5        Disabled Enabled  Normal       20    300      1000     100
     6        Disabled Enabled  Normal       20    300      1000     100
     7        Disabled Enabled  Normal       20    300      1000     100
     8        Disabled Enabled  Normal       20    300      1000     100
     9        Disabled Enabled  Normal       20    300      1000     100
     Dyn1     Enabled  Enabled  Normal       20    300      1000     100

    Note that the Dyn1 interface remains, and MVRP continues to work, despite the switch being in the same physical "state" as in step #1.