Description

The 'force-up' option is not working on mc-ae (MC-LAG) on ACX7100.  Member links of the aggregated trunk work one at a time, but not in an active/active fashion. 

The connected dual homed server can not implemented LACP in this case, so it must be forced up.

Symptoms

An ACX7100 is configured for MC-LAG active/active.  The peering device does not support LACP ,so LACP Force-up is being used.  However, only a single leg will move to a CD state while other leg will remain in an attached state.
 

For example, ACX1 has FUP up and in Collecting/Distributing:

set interfaces ae5 description "HVS-257 Core-N3"
set interfaces ae5 native-vlan-id 101
set interfaces ae5 mtu 2200
set interfaces ae5 aggregated-ether-options lacp system-id 00:01:02:03:04:05
set interfaces ae5 aggregated-ether-options lacp admin-key 5
set interfaces ae5 aggregated-ether-options lacp force-up
set interfaces ae5 aggregated-ether-options mc-ae mc-ae-id 5
set interfaces ae5 aggregated-ether-options mc-ae redundancy-group 1
set interfaces ae5 aggregated-ether-options mc-ae chassis-id 0
set interfaces ae5 aggregated-ether-options mc-ae mode active-active
set interfaces ae5 aggregated-ether-options mc-ae status-control active
set interfaces ae5 aggregated-ether-options mc-ae init-delay-time 240
set interfaces ae5 unit 0 family ethernet-switching interface-mode trunk
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-101-control
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-301-nsi-cm
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-110-volt
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-111-vbng
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-201-dsi
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-401-prov
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-501-public

labroot@f11-42# run show lacp interfaces ae5
Aggregated interface: ae5
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      et-0/0/5 FUP    Actor  Yes    No   Yes  Yes  Yes   Yes     Fast   Passive
      et-0/0/5 FUP  Partner   No   Yes    No   No  Yes   Yes     Fast   Passive
    LACP protocol:        Receive State  Transmit State          Mux State
      et-0/0/5 FUP              Current     No periodic Collecting distributing

labroot@f11-42# run show interfaces mc-ae extensive         
Member Link                  : ae5
Current State Machine's State: mcae active state
Local Status                 : active
Local State                  : up
Peer Status                  : active
Peer State                   : down
     Logical Interface        : ae5.0
     Topology Type            : bridge
     Local State              : up
     Peer State               : down
     Peer Ip/MCP/State        : 10.50.1.2 ae0.0 up

 MCAE Configuration
     Redundancy Group         : 1
     MCAE ID                  : 5
     MCAE Mode                : active_active
     Status Control           : active
     Chassis ID               : 0
LACP Configuration
     System ID                : 00:01:02:03:04:05
     Admin Key                : 5
LACP Information
     Local Partner System ID  : 00:00:00:00:00:00
     Peer Partner System ID   : 00:00:00:00:00:00

But ACX2 is in Detached even though it it is set for Active/Active:

labroot@f11-20# show interfaces ae5 | display set            
set interfaces ae5 description "HVS-257 Core-N3"
set interfaces ae5 native-vlan-id 101
set interfaces ae5 mtu 2200
set interfaces ae5 aggregated-ether-options lacp system-id 00:01:02:03:04:05
set interfaces ae5 aggregated-ether-options lacp admin-key 5
set interfaces ae5 aggregated-ether-options lacp force-up
set interfaces ae5 aggregated-ether-options mc-ae mc-ae-id 5
set interfaces ae5 aggregated-ether-options mc-ae redundancy-group 1
set interfaces ae5 aggregated-ether-options mc-ae chassis-id 1
set interfaces ae5 aggregated-ether-options mc-ae mode active-active
set interfaces ae5 aggregated-ether-options mc-ae status-control standby
set interfaces ae5 aggregated-ether-options mc-ae init-delay-time 240
set interfaces ae5 unit 0 family ethernet-switching interface-mode trunk
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-101-control
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-301-nsi-cm
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-110-volt
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-111-vbng
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-201-dsi
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-401-prov
set interfaces ae5 unit 0 family ethernet-switching vlan members vlan-501-public

[edit]
labroot@f11-20# run show lacp interfaces ae5         
Aggregated interface: ae5
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      et-0/0/48 FUP    Actor   No  Yes    No   No   No   Yes     Fast   Passive
      et-0/0/48 FUP  Partner   No  Yes    No   No   No   Yes     Fast   Passive
    LACP protocol:        Receive State  Transmit State          Mux State 
      et-0/0/48                 Current     No periodic           Attached


labroot@f11-20# run show interfaces mc-ae extensive 
 Member Link                  : ae5
 Current State Machine's State: mcae active state
 Local Status                 : active
 Local State                  : down
 Peer Status                  : active
 Peer State                   : up
     Logical Interface        : ae5.0
     Topology Type            : bridge
     Local State              : down
     Peer State               : up
     Peer Ip/MCP/State        : 10.50.1.1 ae0.0 up
 
 MCAE Configuration
     Redundancy Group         : 1
     MCAE ID                  : 5
     MCAE Mode                : active_active
     Status Control           : standby
     Chassis ID               : 1
 LACP Configuration
     System ID                : 00:01:02:03:04:05
     Admin Key                : 5
 LACP Information
     Local Partner System ID  : 00:00:00:00:00:00
     Peer Partner System ID   : 00:00:00:00:00:00

 

Solution

This is expected behavior for all platforms.  The system will act as a active/standy when LACP is not used on connecting switch or server.  In the case of MC-LAG, the LACP force-up feature will be used for keeping link up.  However, on any particular AE interface only one interface/links can be kept up.  Otherwise, the PE will receive duplicate packets or there can be traffic drops. 

Modification History

2024-02-27 : Article Created
2024-07029:  Adjusted for external publish