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Determining direction of Link Aggregation (LAG) switch using SNMP traps for ASR55K

David Damerjian
Cisco Employee
Cisco Employee

‎01-14-2013 05:43 AM - edited ‎07-05-2021 12:13 PM

LAG (Link Aggregation) SNMP traps that represent a switch from one LAG group of ports to the other, in and of themselves, do not indicate which actual set of LAG ports has become the active (distributing) ports. Here is an example of the traps, along with the log message that gets generated (this log message says the same thing as the traps do):

Sun Jan 13 23:37:45 2013 Internal trap notification 1204 (LAGGroupDown) card:5, port:10, partner:(007F,00-26-88-8D-CF-F0,0039)
Sun Jan 13 23:37:45 2013 Internal trap notification 1205 (LAGGroupUp) card:5, port:10, partner:(007F,00-26-88-A8-47-F0,0039)

2013-Jan-13+23:37:45.142 [lagmgr 179050 warning] [5/0/5526 <lagmgr:0> lagmgr_state.c:1190] [software internal system critical-info syslog] LAG group 50 (global) with master port 5/10 has changed partner from (007F,00-26-88-8D-CF-F0,0039) to (007F,00-26-88-A8-47-F0,0039)

Note that the card number has no significance in indicating which set of ports has become active, as it is referencing the active MMIO, while the port is simply the link aggregation master port (versus member ports).

Now, "show port table [all]" will indeed indicate which is the active set of ports at any given time via the "+" symbol, so for the latest switch, this command can be used to determine the direction of the switch. In the particular example above, the switch was from ports on 5 to 6:

******** show port table all *******

Port  Role Type                      Admin    Oper Link State    Pair  Redundant

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

5/10 Srvc 10G Ethernet              Enabled  -    Up   -         6/10 LA~  5/10

           Untagged                  Enabled  Up   -    Active   -     -

           Tagged VLAN  2011         Enabled  Up   -    Active   -     -

           Tagged VLAN  2405         Enabled  Up   -    Active   -     -

           Tagged VLAN  2015         Enabled  Up   -    Active   -     -

           Tagged VLAN  2427         Enabled  Up   -    Active   -     -

           Tagged VLAN  2407         Enabled  Up   -    Active   -     -

           Tagged VLAN  2441         Enabled  Up   -    Active   -     -

5/11 Srvc 10G Ethernet              Enabled  Up   Up   Active    6/11 LA~  5/10

5/15 Srvc 10G Ethernet              Enabled  Up   Up   Active    6/15 LA~  5/10

5/16 Srvc 10G Ethernet              Enabled  Up   Up   Active    6/16 LA~  5/10

6/10 Srvc 10G Ethernet              Enabled  -    Up   -         5/10 LA+  5/10

           Untagged                  Enabled  Up   -    Active   -     -

           Tagged VLAN  2011         Enabled  Up   -    Active   -     -

           Tagged VLAN  2405         Enabled  Up   -    Active   -     -

           Tagged VLAN  2015         Enabled  Up   -    Active   -     -

           Tagged VLAN  2427         Enabled  Up   -    Active   -     -

           Tagged VLAN  2407         Enabled  Up   -    Active   -     -

           Tagged VLAN  2441         Enabled  Up   -    Active   -     -

6/11 Srvc 10G Ethernet              Enabled  Up   Up   Active    5/11 LA+  5/10

6/15 Srvc 10G Ethernet              Enabled  Up   Up   Active    5/15 LA+  5/10

6/16 Srvc 10G Ethernet              Enabled  Up   Up   Active    5/16 LA+  5/10

But, if there have been multiple LAG switches over time, then one would possibly not have the output of "show port table" from the time period after a particular LAG switch unless they happened to have captured such output at the time.  So, in order to make a determination, one could look further at the actual MAC addresses mentioned in both of the (Up/Down) traps. If you examine the output of "show port info" for any of the ports in both LAG groups, you should see those two MAC addresses listed in the field "Link Aggregation Peer", one address for all the LAG ports on 5 and the other address for all the LAG ports on 6. For example, here is output for one port from each of the LAG groups on MMIOs 5 and 6:

Port: 5/11
  Port Type               : 10G Ethernet
  Role                    : Service Port
  Description             : (None Set)
  Redundancy Mode         : Port Mode
  Framing Mode            : Unspecified
  Redundant With          : 6/11
  Preferred Port          : Non-Revertive
  Physical ifIndex        : 84606976
  Administrative State    : Enabled
  Configured Duplex       : Auto
  Configured Speed        : Auto
  Configured Flow Control : Enabled
  Interface MAC Address   : D8-24-BD-8A-18-EA
  SRP Virtual MAC Address : None
  Fixed MAC Address       : D8-24-BD-8A-18-CA
  Link State              : Up
  Link Duplex             : Full
  Link Speed              : 10 Gb
  Flow Control            : Enabled
  Link Aggregation Group  : 50 (global, member)
  Link Aggregation LACP   : Active, Short, Auto
  Link Aggregation Master : 5/10
  Link Aggregation State  : Agreed with LACP peer
  Link Aggregation Actor  : (8000,D8-24-BD-8A-18-00,001A,8000,050B)
  Link Aggregation Peer   : (007F,00-26-88-8D-CF-F0,0039,007F,0024)
  Logical ifIndex         : 84606977
  Operational State       : Up, Active
  SFP Module              : Present (10G Base-SR)


Port: 6/11
  Port Type               : 10G Ethernet
  Role                    : Service Port
  Description             : (None Set)
  Redundancy Mode         : Port Mode
  Framing Mode            : Unspecified
  Redundant With          : 5/11
  Preferred Port          : Non-Revertive
  Physical ifIndex        : 101384192
  Administrative State    : Enabled
  Configured Duplex       : Auto
  Configured Speed        : Auto
  Configured Flow Control : Enabled
  Interface MAC Address   : D8-24-BD-8A-18-EA
  SRP Virtual MAC Address : None
  Fixed MAC Address       : D8-24-BD-8A-19-0A
  Link State              : Up
  Link Duplex             : Full
  Link Speed              : 10 Gb
  Flow Control            : Enabled
  Link Aggregation Group  : 50 (global, member)
  Link Aggregation LACP   : Active, Short, Auto
  Link Aggregation Master : 5/10
  Link Aggregation State  : Port distributing
  Link Aggregation Actor  : (8000,D8-24-BD-8A-18-00,001A,8000,060B)
  Link Aggregation Peer   : (007F,00-26-88-A8-47-F0,0039,007F,0024)
  Logical ifIndex         : 101384193
  Operational State       : Up, Active
  SFP Module              : Present (10G Base-SR)

Matching up the colored MAC addresses, one can easily determine that the direction of the switch was from 5 to 6:

Sun Jan 13 23:37:45 2013 Internal trap notification 1204 (LAGGroupDown) card:5, port:10, partner:(007F,00-26-88-8D-CF-F0,0039)
Sun Jan 13 23:37:45 2013 Internal trap notification 1205 (LAGGroupUp) card:5, port:10, partner:(007F,00-26-88-A8-47-F0,0039)

Port: 5/11

  Link Aggregation Peer   : (007F,00-26-88-8D-CF-F0,0039,007F,0024)

Port: 6/11

  Link Aggregation Peer   : (007F,00-26-88-A8-47-F0,0039,007F,0024)

In v12.3, additional log messages have been added that will clearly indicate the direction of the switch, but log messages may or may not be available for switches that have taken place farther in the past at the point where the logs have been overwritten in time. Here is an example of a switch from 6 to 5:

2013-Jan-04+09:50:35.280 [snmp 22002 info] [5/0/1754 <lagmgr:0> trap_api.c:1932] [software internal system syslog] Internal trap notification 1205 (LAGGroupUp) card:5, port:10, partner:(007F,2C-6B-F5-73-A3-F0,0034)
2013-Jan-04+09:50:35.280 [snmp 22002 info] [5/0/1754 <lagmgr:0> trap_api.c:1932] [software internal system syslog] Internal trap notification 1204 (LAGGroupDown) card:5, port:10, partner:(007F,2C-6B-F5-72-3D-F0,0034)

2013-Jan-04+09:50:35.280 [lagmgr 179050 warning] [5/0/1754 <lagmgr:0> lagmgr_state.c:1299] [software internal system critical-info syslog] LAG group 50 (global) with master port 5/10 has changed partner from (007F,2C-6B-F5-72-3D-F0,0034) on 6/10, 6/11, 6/15, 6/16 to (007F,2C-6B-F5-73-A3-F0,0034) on 5/10, 5/11, 5/15, 5/16

2013-Jan-04+09:50:35.280 [lagmgr 179043 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:857] [software internal system critical-info syslog] LAG port 6/16 in LAG group 50 (global) collecting=0 distributing=0
2013-Jan-04+09:50:35.280 [lagmgr 179042 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:826] [software internal system critical-info syslog] LAG port 6/16 deselected from LAG group 50 (global)

2013-Jan-04+09:50:35.280 [lagmgr 179043 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:857] [software internal system critical-info syslog] LAG port 6/15 in LAG group 50 (global) collecting=0 distributing=0
2013-Jan-04+09:50:35.280 [lagmgr 179042 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:826] [software internal system critical-info syslog] LAG port 6/15 deselected from LAG group 50 (global)

2013-Jan-04+09:50:35.280 [lagmgr 179043 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:857] [software internal system critical-info syslog] LAG port 6/11 in LAG group 50 (global) collecting=0 distributing=0
2013-Jan-04+09:50:35.280 [lagmgr 179042 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:826] [software internal system critical-info syslog] LAG port 6/11 deselected from LAG group 50 (global)

2013-Jan-04+09:50:35.280 [lagmgr 179043 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:857] [software internal system critical-info syslog] LAG port 6/10 in LAG group 50 (global) collecting=0 distributing=0
2013-Jan-04+09:50:35.280 [lagmgr 179042 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:826] [software internal system critical-info syslog] LAG port 6/10 deselected from LAG group 50 (global)

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

2013-Jan-04+09:50:35.280 [lagmgr 179043 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:857] [software internal system critical-info syslog] LAG port 5/16 in LAG group 50 (global) collecting=1 distributing=1
2013-Jan-04+09:50:35.280 [lagmgr 179041 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:819] [software internal system critical-info syslog] LAG port 5/16 selected in LAG group 50 (global)

2013-Jan-04+09:50:35.280 [lagmgr 179043 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:857] [software internal system critical-info syslog] LAG port 5/15 in LAG group 50 (global) collecting=1 distributing=1
2013-Jan-04+09:50:35.280 [lagmgr 179041 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:819] [software internal system critical-info syslog] LAG port 5/15 selected in LAG group 50 (global)

2013-Jan-04+09:50:35.280 [lagmgr 179043 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:857] [software internal system critical-info syslog] LAG port 5/11 in LAG group 50 (global) collecting=1 distributing=1
2013-Jan-04+09:50:35.280 [lagmgr 179041 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:819] [software internal system critical-info syslog] LAG port 5/11 selected in LAG group 50 (global)

2013-Jan-04+09:50:35.280 [lagmgr 179043 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:857] [software internal system critical-info syslog] LAG port 5/10 in LAG group 50 (global) collecting=1 distributing=1
2013-Jan-04+09:50:35.280 [lagmgr 179041 info] [5/0/1754 <lagmgr:0> lagmgr_state.c:819] [software internal system critical-info syslog] LAG port 5/10 selected in LAG group 50 (global)

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

2013-Jan-04+09:50:35.262 [lagmgr 179040 info] [5/0/1754 <lagmgr:0> lagmgr_config.c:2507] [software internal system critical-info syslog] LAG port 6/16 left LAG group 50 (global)
2013-Jan-04+09:50:35.262 [lagmgr 179040 info] [5/0/1754 <lagmgr:0> lagmgr_config.c:2507] [software internal system critical-info syslog] LAG port 6/15 left LAG group 50 (global)
2013-Jan-04+09:50:35.262 [lagmgr 179040 info] [5/0/1754 <lagmgr:0> lagmgr_config.c:2507] [software internal system critical-info syslog] LAG port 6/11 left LAG group 50 (global)
2013-Jan-04+09:50:35.262 [lagmgr 179040 info] [5/0/1754 <lagmgr:0> lagmgr_config.c:2507] [software internal system critical-info syslog] LAG port 6/10 left LAG group 50 (global)
 

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