MLAG Procedures and Troubleshooting

Version 12

    This post supply a list of procedures and troubleshooting options when using MLAG.

    This post is advanced and meant for users familiar with MLAG configuration and considerations.

     

    Table of Contents

     

    References

     

    Note: before you start troubleshooting, make sure that you are aligned with the latest GA version of MLNX-OS.

     

    Basic Requirements

    • IP address of mlag-vip must be in same subnet as the MGMT ports
    • MGMT0 must be used for MLAG. In case a switch is not available to connect management ports, back to back connection is acceptable. No need for cross-connect cable.
    • The switch CPU types must match (x86 or PPC).
    • The IPL IP address must not overlap with any other address on the switch. It can belong to a /30 subnet. It is local to this switch and never needs to be advertised to any other switch.

     

    The Good Condition

    In order to configure MLAG as follows, follow HowTo Configure MLAG on Mellanox Switches.

     

    Here is output references from a good condition of MLAG setup as follows:

    MLAG troubleshooting - New Page.png

     

    Output of SX03:

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show mlag

    Admin status: Enabled

    Operational status: Up

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   0

    Enabled:    1

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 0

    Active-full:    1

     

    MLAG IPLs Summary:

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Up           10.10.10.1      10.10.10.2     

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:54:88  Up        <mti-mar-sx03>

    E4:1D:2D:37:50:88  Up         mti-mar-sx04

     

     

     

     

     

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show mlag-vip

    MLAG VIP

    ========

    MLAG group name: my-mlag-vip-domain

    MLAG VIP address: 10.20.2.205/24

    Active nodes: 2

     

     

    Hostname             VIP-State            IP Address         

    ----------------------------------------------------

    mti-mar-sx03         master               10.20.2.53         

    mti-mar-sx04         standby              10.20.2.54         

    mti-mar-sx03 [my-new-domain: master] (config) #

     

     

    Output SX04:

    mti-mar-sx04 [my-mlag-vip-domain: standby] (config) # show mlag

    Admin status: Enabled

    Operational status: Up

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   0

    Enabled:    1

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 0

    Active-full:    1

     

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Up           10.10.10.2      10.10.10.1     

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:50:88  Up        <mti-mar-sx04>

    E4:1D:2D:37:54:88  Up         mti-mar-sx03

     

     

     

     

    mti-mar-sx04 [my-mlag-vip-domain: standby] (config) # show mlag-vip

    MLAG VIP

    ========

    MLAG group name: my-mlag-vip-domain

    MLAG VIP address: 10.20.2.205/24

    Active nodes: 2

     

     

    Hostname             VIP-State            IP Address         

    ----------------------------------------------------

    mti-mar-sx03         master               10.20.2.53         

    mti-mar-sx04         standby              10.20.2.54         

    mti-mar-sx04 [my-new-domain: standby] (config) #

     

     

     

    1. HowTo Change the MLAG VIP domain name

     

    MLAG VIP Domain act as an ID that binds two pair of switches to the same MLAG domain.

    Once assigned to both switches, one will be selected as a master while the other will be selected as a standby.

     

    To change the MLAG VIP domain name, you will need to unmap the switch from the MLAG domain and re-map it again with a new name.

     

    For example changing the domain name from my-mlag-vip-domain to my-new-domain

     

    Standby switch:

    mti-mar-sx04 [my-mlag-vip-domain: standby] (config) # no mlag-vip

    mti-mar-sx04 [standalone: master] (config) # mlag-vip my-new-domain ip 10.20.2.205 /24 force

    mti-mar-sx04 [my-new-domain: *unknown*] (config) #

    mti-mar-sx04 [my-new-domain: *unknown*] (config) #

    mti-mar-sx04 [my-new-domain: *unknown*] (config) #

    mti-mar-sx04 [my-new-domain: master] (config) #

    mti-mar-sx04 [my-new-domain: master] (config) #

    mti-mar-sx04 [my-new-domain: master] (config) #

     

    Master switch:

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # no mlag-vip

    mti-mar-sx03 [standalone: master] (config) #  mlag-vip my-new-domain ip 10.20.2.205 /24 force

    mti-mar-sx03 [my-new-domain: *unknown*] (config) #

    mti-mar-sx03 [my-new-domain: standby] (config) #

    mti-mar-sx03 [my-new-domain: standby] (config) #

     

    In normal condition, the IPL link should be configured as port-channel with 2 or more ports, so there is a rare condition that both of the ports will be in down state.

    In this case only the master switch will pass traffic.

     

    Regularly, when we run show mlag command, we will get (only one mlag-port-channel port is configured in this case) :

     

    Master:

    mti-mar-sx04 [my-new-domain: master] (config) # show mlag

    Admin status: Enabled

    Operational status: Up

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   0

    Enabled:    1

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 0

    Active-full:    1

     

    MLAG IPLs Summary:

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Up           10.10.10.2      10.10.10.1     

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:50:88  Up        <mti-mar-sx04>

    E4:1D:2D:37:54:88  Up         mti-mar-sx03

    mti-mar-sx04 [my-new-domain: master] (config) #

     

    Standby:

    mti-mar-sx03 [my-new-domain: standby] (config) # show mlag

    Admin status: Enabled

    Operational status: Up

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   0

    Enabled:    1

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 0

    Active-full:    1

     

     

    MLAG IPLs Summary:

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Up           10.10.10.1      10.10.10.2     

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:54:88  Up        <mti-mar-sx03>

    E4:1D:2D:37:50:88  Up         mti-mar-sx04

    mti-mar-sx03 [my-new-domain: standby] (config) #

     

    When shutting down the IPL port on the master switch:

     

    mti-mar-sx04 [my-new-domain: master] (config) # interface port-channel 1 shutdown

    mti-mar-sx04 [my-new-domain: master] (config) # show mlag

    Admin status: Enabled

    Operational status: Up

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   0

    Enabled:    1

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 0

    Active-full:    1

     

    MLAG IPLs Summary:

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Down        10.10.10.2      10.10.10.1     

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:50:88  Up        <mti-mar-sx04>

    E4:1D:2D:37:54:88  Down      mti-mar-sx03

     

    mti-mar-sx04 [my-new-domain: master] (config) #

     

    Standby switch:

    mti-mar-sx03 [my-new-domain: standby] (config) # show mlag

    Admin status: Enabled

    Operational status: Down

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   1

    Enabled:    0

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 0

    Active-full:    1

     

    MLAG IPLs Summary:

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Down        10.10.10.1      10.10.10.2     

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:54:88  Peering  <mti-mar-sx03>

    E4:1D:2D:37:50:88  Down      mti-mar-sx04

    mti-mar-sx03 [my-new-domain: standby] (config) #

     

     

    3. 'Inactive Ports' and 'Active-Partial' Status on the show mlag command

    The main reason for that could be that the mlag-port-channel is down.

    All ethernet ports are admin UP by default, however the mlag-port-channel are down by default. The reason behind it is that in most cases you wish to finish all network configuration and then enable the mlag-port channel.

     

    So, when creating mlag-port-channel and adding ethernet interface to it (either static or LACP), don't forget to enable the port.

     

    Note: When one port is down, it doesn't mean that the whole mlag-port-channel is down.

     

    MLAG Ports Status Summary:

    • Inactive - all ports in the mlag-port-channel are down (on both switches).
    • Active-partial - some ports are down (example below, on one switch)
    • Active-full - normal condition, all is good.

     

    Here is the symptom (when one mlag-port-channel is down):

    mti-mar-sx03 [my-new-domain: master] (config) # interface mlag-port-channel 10 shutdown

    mti-mar-sx03 [my-new-domain: master] (config) # show mlag

    Admin status: Enabled

    Operational status: Up

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   0

    Enabled:    1

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 1

    Active-full:    0

     

    MLAG IPLs Summary:

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Up           10.10.10.1      10.10.10.2     

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:54:88  Up        <mti-mar-sx03>

    E4:1D:2D:37:50:88  Up         mti-mar-sx04

    mti-mar-sx03 [my-new-domain: master] (config) #

     

    Enabling it back:

    mti-mar-sx03 [my-new-domain: master] (config) # interface mlag-port-channel 10 no shutdown

    mti-mar-sx03 [my-new-domain: master] (config) # show mlag

    Admin status: Enabled

    Operational status: Up

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D

     

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   0

    Enabled:    1

     

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 0

    Active-full:    1

     

     

    MLAG IPLs Summary:

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Up           10.10.10.1      10.10.10.2     

     

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:54:88  Up        <mti-mar-sx03>

    E4:1D:2D:37:50:88  Up         mti-mar-sx04

    mti-mar-sx03 [my-new-domain: master] (config) #

     

    4. Spanning Tree and MLAG

    Wrong use of spanning tree in general may block unwanted port on the network. When using MLAG it is recommended to turn off Spanning Tree on the switch

     

    To disable spanning tree globally on the switch, run on both switches:

    mti-mar-sx03 [my-new-domain: master] (config) # no spanning tree

     

    5. Management Port connectivity - mgmt0

    For MLAG, mgmt0 interfaces on both switches should be on the same subnet.

    if for any reason, the mgmt1 is used for the switch management MLAG will not work, it requires specifically mgmt0 IP connectivity with the other switch. In such case you need to connect mgmt0 back-to-back with the other switch.

     

    6. Management Port is Down but IPL port is UP

    In case when there is no ping between the two servers on mgmt0 (e.g. mgmt0 port is Down, or any management switch problem that blocks traffic between the switches on mgmt0) - both switches will pass traffic.

    There is no mentioning of the second switch in the cluster. The show mlag and show mlag-vip output will look like this below:

    mti-mar-sx04 [my-new-domain: master] (config) # show mlag

    Admin status: Enabled

    Operational status: Up

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   0

    Enabled:    1

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 0

    Active-full:    1

     

    MLAG IPLs Summary:

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Up           10.10.10.2      10.10.10.1     

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:50:88  Up        <mti-mar-sx04>

    E4:1D:2D:37:54:88  Up         -

    mti-mar-sx04 [my-new-domain: master] (config) #

    mti-mar-sx04 [my-new-domain: master] (config) # show mlag-vip

    MLAG VIP

    ========

    MLAG group name: my-new-domain

    MLAG VIP address: 10.20.2.205/24

    Active nodes: 1

     

     

    Hostname             VIP-State            IP Address         

    ----------------------------------------------------

    mti-mar-sx04         master               10.20.2.54         

    mti-mar-sx04 [my-new-domain: master] (config) #

     

    7. Connecting four switches in 2 MLAG domains

    The best practice in this case is to have only one mlag-port-channel with all the ports connecting between the leafs and the spines, to avoid loops.

     

    8. LACP vesus Static

    Make sure to configure LACP (active, passive) or static mode (on) on all mlag ports and on all server ports. Setting static mode on one side while LACP on the other side will not work.

     

    9. Debugging MLAG Cluster issues

     

    - After adding the two switches to the cluster, wait for a few seconds. One switch will become Master, while the other one will become the slave. When performing remove/add/cluster change operations, always wait for the switch to go to “standalone master” before continuing.

    - Run "show mlag-vip"

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show mlag-vip

    MLAG VIP

    ========

    MLAG group name: my-mlag-vip-domain

    MLAG VIP address: 10.20.2.205/24

    Active nodes: 2

     

     

    Hostname             VIP-State            IP Address        

    ----------------------------------------------------

    mti-mar-sx03         master               10.20.2.53        

    mti-mar-sx04         standby             10.20.2.54        

    mti-mar-sx03 [my-new-domain: master] (config) #

    Verify that the two switches are in the cluster. The other MLAG switch must reflect the same information.

     

    Note: If one switch does not see this MLAG-Domain do the following:

    Run "show ip route"

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show ip route

     

    VRF Name:         default

    -----------------------------

    Destination       Mask              Gateway           Interface         Source            Distance/Metric

    default           0.0.0.0           10.20.0.251       mgmt0             DHCP              0/0

    10.20.0.0         255.255.0.0       0.0.0.0           mgmt0             direct            0/0

    10.10.10.0        255.255.255.0     0.0.0.0   

     

    The management subnet must only point out of the MGMT port. inband management is acceptable. If there is a conflict, the MGMT Keep alive is sent out on the wrong port and not advertised to other switch.

     

    In case the switch still does not see the cluster: The MGMT keep alive is broadcast to a well know multicast DNS group – 224.0.0.251. Check to see if both switches are advertising to this group. It is likely that the mgmt. port will see a lot of traffic. This output will need to be captured and analyzed.

     

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # tcpdump -i mgmt0

    tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

    listening on mgmt0, link-type EN10MB (Ethernet), capture size 96 bytes

     

    06:42:15.330780 IP mti-mar-sx03.mti.labs.mlnx.mdns > 224.0.0.251.mdns:  0 [2a] PTR (Cache flush)? _tcn_MLAG-DOMAIN._tcp.local. (117)

     

    This is a transmission from master to the multicast group. Before we have a master, both switches will see this frame and both will transmit it. After the cluster is formed, only the master will transmit this. If this frame is not seen, the cluster will not form.

     

    10. Debugging IPL issues

    IPL Link needs to be up for MLAG peer ports and sync data to be available. The IPL VLAN is local to the MLAG switches and can be any number. VLAN 4000 or higher is typically used for control vlans and is recommended.

    Show mlag command shows IPL link state and other valuable information.

    The IPL link needs to be Up. Both the switches must be in Up State in the Member summary. Peering or down is not a good state. Peering could be a transient state but should move to UP eventually.

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show mlag

    Admin status: Enabled

    Operational status: Up

    Reload-delay: 30 sec

    Keepalive-interval: 1 sec

    Upgrade-timeout: 60 min

    System-mac: 00:00:5E:00:01:5D << Both switches should show the same System MAC Address

     

    MLAG Ports Configuration Summary:

    Configured: 1

    Disabled:   0

    Enabled:    1

     

    MLAG Ports Status Summary:

    Inactive:       0

    Active-partial: 0

    Active-full:    1

     

    MLAG IPLs Summary:

    ID   Group         Vlan       Operational  Local           Peer

         Port-Channel  Interface  State        IP address      IP address

    --------------------------------------------------------------------------

    1    Po1           4000       Up           10.10.10.1      10.10.10.2    

     

    MLAG Members Summary:

    System-id          State     Hostname

    -------------------------------------

    E4:1D:2D:37:54:88  Up        <mti-mar-sx03>

    E4:1D:2D:37:50:88  Up         mti-mar-sx04

     

    In case IPL is up and still member ports are not visible, try ping the remote IPL interface. Ping the local switch and then the MLAG Peer switch IPL IP address.  If ping doesn’t go through use tcpdump to debug this case. In case link is up and ping is lossy, check for traffic on the IPL interface. During normal operation, IPL traffic is a few frames per second at the most. If you see a lot of traffic, it is likely an indication of a loop in the setup.

     

    switch (config) # tcpdump -i vlan4000

     

    The other usual suspects are checking if both sides are set to static, or lacp. Check interface transceiver for matching serial numbers to identify cabling issues.

     

    11. Debugging MLAG port issues

    A healthy MLAG should show all ports as UP (P) and MLAG must be (U).

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show interface mlag-port-channel summary

    MLAG Port-Channel Flags: D-Down, U-Up

                             P-Partial UP, S - suspended by MLAG

    Port Flags: D - Down, P - Up in port-channel (members)

                S - Suspend in port-channel (members), I - Individual

     

    Group

    Port-Channel      Type       Local Ports              Peer Ports

    (D/U/P/S)                    (D/P/S/I)                (D/P/S/I)

    --------------------------------------------------------------------------------

    1 Mpo1(U)         LACP        Eth1/10(P)                Eth1/10(P)

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) #

     

    Partial means that all ports are down on the MLAG-peer switch side. This could result from interface MLAG being shut on the remote side or mlag protocol shut on remote side.

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show interface mlag-port-channel summary

    MLAG Port-Channel Flags: D-Down, U-Up

                             P-Partial UP, S - suspended by MLAG

    Port Flags: D - Down, P - Up in port-channel (members)

                S - Suspend in port-channel (members), I - Individual

     

    Group

    Port-Channel      Type       Local Ports              Peer Ports

    (D/U/P/S)                    (D/P/S/I)                (D/P/S/I)

    --------------------------------------------------------------------------------

    1 Mpo1(P)         LACP       Eth1/10(P)                 Eth1/10(D)

     

    Peer ports not being visible means that ports in the MLAG-Peer switch are either not added in the MLAG or there are cluster issues.

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show interface mlag-port-channel summary

    MLAG Port-Channel Flags: D-Down, U-Up

                             P-Partial UP, S - suspended by MLAG

    Port Flags: D - Down, P - Up in port-channel (members)

                S - Suspend in port-channel (members), I - Individual

     

     

    Group

    Port-Channel      Type       Local Ports              Peer Ports

    (D/U/P/S)                    (D/P/S/I)                (D/P/S/I)

    --------------------------------------------------------------------------------

    1 Mpo1(P)         LACP      Eth1/10(P)

    SX1012-B [MLAG-DOMAIN: master] (config) #

     

    If the physical port shows (S) that could result from either receiving no PDUs from the remote side or by receiving a PDU that doesn’t match what is being received on other members of the MLAG port-channel

    Check the lacp counters to see continuous increment of counters, both sent and receive must increment. One every second for fast retransmit and one every 30 seconds for slow retransmit.

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show lacp counters

    LACPDUs     Marker     Marker Response      LACPDUs

    Port      Sent Recv      Sent Recv         Sent Recv        Illegal    Unknown

    -----------------------------------------------------------------------------

     

    ...

     

    Mlag-port-channel: 1

    ------------------

    1/10       0   0           0   0             35  27             0       0

     

    In case the lacp counters are incrementing and port is still down, then check the SID received on different port of the MLAG.  They should match across all MLAG ports.

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) #show lacp interfaces neighbors

    Flags:

    A - Device is in Active mode

    P - Device is in Passive mode

     

    MLAG channel group 1 neighbors

     

    Port 1/10

    ----------

    Partner System ID               : e4:1d:2d:37:48:80  (This is the System-ID received on this port from the remote switch. It must match for all ports connected to the same switch)

    Partner System priority         : 32768

    Flags                           : A

    LACP Partner Port Priority      : 32768

    LACP Partner Oper Key           : 13845 (LACP OPER KEY must match across all ports in the same MLAG port-channel)

    LACP Partner Port State         : 0xbc

     

    Port State Flags Decode

    ------------------------

    Activity : Active

    Aggregation State : Aggregation, Sync, Collecting, Distributing,

     

    To check the SID used by the Mellanox switch use this command:

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show lacp interfaces  mlag-port-channel 1 system-identifier

    Priority: 32768

    MAC:      00:00:5E:00:01:06

     

    Check the lacp property across all ports in an MLAG

    mti-mar-sx03 [my-mlag-vip-domain: master] (config) # show lacp interfaces eth 1/10

    Port : 1/10

    -------------

     

    Port State = Bundle

    MLAG Channel Group : 1

    Pseudo mlag-port-channel = Mpo1

    LACP port-priority = 32768

    LACP Rate = Slow

    LACP Activity : Active

    LACP Timeout : Short

     

    Aggregation State : Aggregation, Sync, Collecting, Distributing,

     

                        LACP Port  Admin   Oper  Port       Port

    Port     State      Priority   Key     Key   Number     State

    -------------------------------------------------------------------

    1/7      Bundle     32768      29001  29001  0x7        0x0

    (This is what we advertise to the remote switch- the Admin and Oper keys must match across all ports in a port-channel)

     

    12. General Debugging Tips and other considerations

    • It is possible that a port is down when it is in MLAG mode.  You can always check the physical link by taking the port out of the MLAG.

    • Cluster is not required for MLAG connectivity but is a best practice and is require for detection of split brain (when both switches active, but can't see each other).
    • When any one switch is rebooted, the mlag ports on the mlag peer switch are not flapped.
    • LACP is highly recommended for MLAG- especially if the remote peer is a switch. This will ensure a second level of sanity and identify any wiring issues.