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mricardez
Staff
Staff
June 3, 2025

Technical Tip: FortiSwitch how to interpret the uptimes of MCLAG

  • June 3, 2025
  • 0 replies
  • 832 views
Description This article describes how to interpret the uptimes using MCLAG CLIs.
Scope FortiSwitch v7.0 and earlier.
Solution

The multichassis LAG (MCLAG) group LACP interfaces of two FortiSwitch (node-level redundancy).

 

About MCLAG in FortiSwitch.

 

During a troubleshooting session, the uptime values could give a clue of LACP negotiation of the LACP from each node.

 

  1. 'diagnose switch mclag list' is to show mclag trunks (non-ICL trunks), which shows both local and remote trunk uptime.

 

To get local or remote trunk uptime, use 'diagnose switch trunk summary' or 'diagnose switch trunk list <trunk name (optional)>' on the local or remote, respectively.

 

For example:

 

lxie2-248ep-1 # diagnose switch trunk summary  Trunk Name Mode PSC MAC Status Up Time ________________ _________________________ ___________ _________________ ___________ _________________________________  4DN5018000717-0 lacp-active(auto-isl,mclag) src-dst-ip 70:4C:A5:F6:83:F4 up(2/2) 3 days,21 hours,51 mins,14 secs 4ENTF18001440-0 lacp-active(auto-isl,mclag) src-dst-ip 70:4C:A5:F6:83:F6 up(2/2) 3 days,21 hours,51 mins,14 secs 8EP5919000008-0 lacp-active(auto-isl,mclag) src-dst-ip 70:4C:A5:F6:84:00 up(2/2) 3 days,21 hours,51 mins,14 secs <<<<<< local 8EP5919000008-0 uptime _FlInK1_ICL0_ lacp-active(auto-isl,mclag-icl) src-dst-ip 70:4C:A5:F6:83:FA up(2/2) 3 days,21 hours,50 mins,29 secs G101ETK19005973 lacp-active(auto-isl,mclag) src-dst-ip 70:4C:A5:F6:83:FD up(1/1) 3 days,21 hours,51 mins,11 secs    lxie2-248ep-1 # diagnose switch mclag list 8EP5919000008-0 (*) - Using local system-id in LACP BPDU  8EP5919000008-0(*) ------------------     Local system ID 70:4c:a5:f6:84:00     Peer system ID 70:4c:a5:f6:84:00     Current system ID 70:4c:a5:f6:84:00     Local ports 51-52     Peer ports 51-52     Local uptime 3 days 21h:51m:15s <<<<<< local trunk uptime     Peer uptime 3 days 21h:50m:29s     Local LAG is configured as LACP active.     Atleast one local LAG port is UP.     Peer LAG is configured as LACP active     Atleast one peer LAG port is UP,     local LAG ports are filtered for ICL traffic.     Updates sent to peer 312456     Updates received from peer 312449 

 

  1. 'diagnose switch mclag icl' shows local and remote system uptimes, which are compared with 'get system performance status' on the local and remote switch, respectively.

For example:

 

lxie2-248ep-1 # get system performance status CPU states: 12% user 27% system 0% nice 61% idle Memory states: 47% used Average network usage: 0 kbps in 1 minute, 0 kbps in 10 minutes, 0 kbps in 30 minutes Uptime: 3 days, 22 hours, 0 minutes <<<<< local system up time  lxie2-248ep-1 # diagnose switch mclag icl _FlInK1_ICL0_     icl-ports 45-46     egress-block-ports 39-42,48,51-52     interface-mac 70:4c:a5:f6:83:cd     local-serial-number S248EPTF18002170     peer-mac 70:4c:a5:e1:6e:c1     peer-serial-number S248EPTF18001969     Local uptime 3 days 22h: 0m: 0s <<<<<< local system uptime     Peer uptime 3 days 22h: 0m: 0s     MCLAG-STP-mac 70:4c:a5:e1:6e:c0     keepalive interval 1     keepalive timeout 60     dormant candidate Peer     split-brain Disabled  Counters     received keepalive packets 312818     transmited keepalive packets 312825
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