Description

This article illustrates the behaviour of MC-AE interface upon ICCP Down with and without prefer-status-control-active configuration.

 

Upon ICCP Down, all mc-lag port flap and below is how MC-LAG should behaves from URL below:

https://www.juniper.net/documentation/us/en/software/junos/mc-lag/topics/concept/best-practices-usage-notes.html

 

 

Symptoms

Per URL, You can configure prefer-status-control-active statement with the status-control standby configuration to prevent the LACP mc-ae system ID from reverting to the LACP default system ID during an ICCP failure. 

First at all, the example in this test use ae0 as ICCP with physical member et-0/0/50 and et-0/0/51. ae1 configure as Active in QFX5110-1 and backup in QFX5110-2. 
    et-0/0/50 {
        ether-options {
            802.3ad ae0;
        }
    }
    et-0/0/51 {
        ether-options {
            802.3ad ae0;
    ae0 {
        description Inter-Link_for_ICCP_ICL;
        aggregated-ether-options {
            lacp {
                active;
            }
        }

QFX5110-1 ae1 config as status-control active 
     ae1 {
        aggregated-ether-options {
            lacp {
                active;
                periodic fast;
                system-id 00:11:00:22:00:01;
                admin-key 1;
            }
            mc-ae {
                mc-ae-id 1;
                redundancy-group 2;
                chassis-id 1;
                mode active-active;
                status-control active;
                init-delay-time 240;

QFX5110-2 ae1 config as status-control standby 
    ae1 {
        aggregated-ether-options {
            lacp {
                active;
                periodic fast;
                system-id 00:11:00:22:00:01;
                admin-key 1;
            }
            mc-ae {
                mc-ae-id 1;
                redundancy-group 2;
                chassis-id 0;
                mode active-active;
                status-control standby;
                init-delay-time 240;

 

Solution

Below Test illustrates mc-ae behaviour with and without Prefer-status-control-active.

Case A: Prefer-status-control-active NOT Configured
  1.  Disable et-0/0/50 and et-0/0/51, ae0 down
  2.  Hence, ICCP down
  3.  While ICCP Down, MC-LAG AE port in QFX5110-1 flap once and MC-LAG AE Port in QFX5110-2 flip once due to LACP ID change from configured value to default value
  4. Before ICCP Down – AE1 in QFX5110-1 and QFX5110-2 used configured LACP ID: 00:11:00:22:00:01 
    labroot@QFX5110-1> show lacp interfaces ae1 extensive 
Sep 12 15:42:22
Aggregated interface: ae1
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      ge-0/0/0       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      ge-0/0/0     Partner    No    No   Yes  Yes  Yes   Yes     Fast    Active
    LACP protocol:        Receive State  Transmit State          Mux State 
      ge-0/0/0                  Current   Fast periodic Collecting distributing
    LACP info:        Role     System             System       Port     Port    Port 
                             priority         identifier   priority   number     key 
      ge-0/0/0       Actor        127  00:11:00:22:00:01        127    32769       1
      ge-0/0/0     Partner        127  68:22:8e:64:fa:40        127        1       1
 
labroot@QFX5110-2> show lacp interfaces ae1 extensive 
Sep 12 15:42:28
Aggregated interface: ae1
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      ge-0/0/0       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      ge-0/0/0     Partner    No    No   Yes  Yes  Yes   Yes     Fast    Active
    LACP protocol:        Receive State  Transmit State          Mux State 
      ge-0/0/0                  Current   Fast periodic Collecting distributing
    LACP info:        Role     System             System       Port     Port    Port 
                             priority         identifier   priority   number     key 
      ge-0/0/0       Actor        127  00:11:00:22:00:01        127        1       1
      ge-0/0/0     Partner        127  68:22:8e:64:fa:40        127        2       1

    #After ICCP Down AE1 in QFX5110-1 and QFX5110-2 used default LACP ID: d8:53:9a:56:f3:20   
    labroot@QFX5110-1> show lacp interfaces ae1 extensive 
Sep 12 15:44:09
Aggregated interface: ae1
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      ge-0/0/0       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      ge-0/0/0     Partner    No    No   Yes  Yes  Yes   Yes     Fast    Active
    LACP protocol:        Receive State  Transmit State          Mux State 
      ge-0/0/0                  Current   Fast periodic Collecting distributing
    LACP info:        Role     System             System       Port     Port    Port 
                             priority         identifier   priority   number     key 
      ge-0/0/0       Actor        127  d8:53:9a:56:f3:20        127    32769       1
      ge-0/0/0     Partner        127  68:22:8e:64:fa:40        127        1       1
 
labroot@QFX5110-2> show lacp interfaces ae1 extensive 
Sep 12 15:44:15
Aggregated interface: ae1
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      ge-0/0/0       Actor    No    No    No   No  Yes   Yes     Fast    Active
      ge-0/0/0     Partner    No    No    No   No   No   Yes     Fast    Active
    LACP protocol:        Receive State  Transmit State          Mux State 
      ge-0/0/0                  Current   Fast periodic           Attached
    LACP info:        Role     System             System       Port     Port    Port 
                             priority         identifier   priority   number     key 
      ge-0/0/0       Actor        127  d8:53:9a:56:53:20        127        1       1
      ge-0/0/0     Partner        127  68:22:8e:64:fa:40        127        2       1
  5.  After AE0 resume and then ICCP Up around 1 mins, MC-LAG AE port in QFX5110-1 flap again due to LACP ID change from default value to configured value and MC-LAG AE Port in QFX5110-2 up   
    labroot@QFX5110-1> show lacp interfaces ae1 extensive 
Sep 12 15:47:44
Aggregated interface: ae1
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      ge-0/0/0       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      ge-0/0/0     Partner    No    No   Yes  Yes  Yes   Yes     Fast    Active
    LACP protocol:        Receive State  Transmit State          Mux State 
      ge-0/0/0                  Current   Fast periodic Collecting distributing
    LACP info:        Role     System             System       Port     Port    Port 
                             priority         identifier   priority   number     key 
      ge-0/0/0       Actor        127  00:11:00:22:00:01        127    32769       1
     ge-0/0/0     Partner        127  68:22:8e:64:fa:40        127        1       1
 
labroot@QFX5110-2> show lacp interfaces ae1 extensive 
Sep 12 15:47:40
Aggregated interface: ae1
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      ge-0/0/0       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      ge-0/0/0     Partner    No    No   Yes  Yes  Yes   Yes     Fast    Active
    LACP protocol:        Receive State  Transmit State          Mux State 
      ge-0/0/0                  Current   Fast periodic Collecting distributing
    LACP info:        Role     System             System       Port     Port    Port 
                             priority         identifier   priority   number     key 
      ge-0/0/0       Actor        127  00:11:00:22:00:01        127        1       1
      ge-0/0/0     Partner        127  68:22:8e:64:fa:40        127        2       1
  6. ae interface up/down timestamp, traffic should be impacted for a few second while ae1 in QFX5110-1 flaps 
    #ICCP ae0 down when et-0/0/50 and et-0/0/51 disabled
labroot@QFX5110-1> show log messages | match SNMP_TRAP_LINK | match ae0 
Sep 12 15:48:14
ep 12 15:43:27  QFX5110-1 mib2d[11099]: SNMP_TRAP_LINK_DOWN: ifIndex 4147, ifAdminStatus up(1), ifOperStatus down(2), ifName ae0
Sep 12 15:45:45  QFX5110-1 mib2d[11099]: SNMP_TRAP_LINK_UP: ifIndex 4147, ifAdminStatus up(1), ifOperStatus up(1), ifName ae0
 
#QFX5110-1 ae1 flap twice during LACP ID change to default and then back configured Value
labroot@QFX5110-1> show log messages | match SNMP_TRAP_LINK | match ae1$   
Sep 12 15:48:23
Sep 12 15:43:28  QFX5110-1 mib2d[11099]: SNMP_TRAP_LINK_DOWN: ifIndex 4148, ifAdminStatus up(1), ifOperStatus down(2), ifName ae1
Sep 12 15:43:31  QFX5110-1 mib2d[11099]: SNMP_TRAP_LINK_UP: ifIndex 4148, ifAdminStatus up(1), ifOperStatus up(1), ifName ae1
Sep 12 15:46:52  QFX5110-1 mib2d[11099]: SNMP_TRAP_LINK_DOWN: ifIndex 4148, ifAdminStatus up(1), ifOperStatus down(2), ifName ae1
Sep 12 15:46:54  QFX5110-1 mib2d[11099]: SNMP_TRAP_LINK_UP: ifIndex 4148, ifAdminStatus up(1), ifOperStatus up(1), ifName ae1
 
#QFX5110-2 ae1 down when ae0 down and coming back up when ae0+ICCP restore.
labroot@QFX5110-2> show log messages | match SNMP_TRAP_LINK | match ae1$ 
Sep 12 15:49:54
Sep 12 15:43:28  QFX5110-2 mib2d[9502]: SNMP_TRAP_LINK_DOWN: ifIndex 4144, ifAdminStatus up(1), ifOperStatus down(2), ifName ae1
Sep 12 15:46:54  QFX5110-2 mib2d[9502]: SNMP_TRAP_LINK_UP: ifIndex 4144, ifAdminStatus up(1), ifOperStatus up(1), ifName ae1

Case B: Prefer-status-control-active Configured
  1. Add below config in QFX5110-1 
    set interfaces ae1 aggregated-ether-options mc-ae events iccp-peer-down prefer-status-control-active

     
  2. same as case A, disable et-0/0/50 and et-0/0/51, then ae0 + ICCP down, this time, LACP ID in QFX5110-1 remains unchanged and QFX5110-2 change to default value(no impact as ae1 in QFX5110-2 is down).  
    labroot@QFX5110-1> show lacp interfaces ae1 extensive 
Sep 12 15:57:52
Aggregated interface: ae1
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      ge-0/0/0       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      ge-0/0/0     Partner    No    No   Yes  Yes  Yes   Yes     Fast    Active
    LACP protocol:        Receive State  Transmit State          Mux State 
      ge-0/0/0                  Current   Fast periodic Collecting distributing
    LACP info:        Role     System             System       Port     Port    Port 
                             priority         identifier   priority   number     key 
      ge-0/0/0       Actor        127  00:11:00:22:00:01        127    32769       1
      ge-0/0/0     Partner        127  68:22:8e:64:fa:40        127        1       1
 
labroot@QFX5110-2> show lacp interfaces ae1 extensive 
Sep 12 15:58:06
Aggregated interface: ae1
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      ge-0/0/0       Actor    No    No    No   No  Yes   Yes     Fast    Active
      ge-0/0/0     Partner    No    No    No   No   No   Yes     Fast    Active
    LACP protocol:        Receive State  Transmit State          Mux State 
      ge-0/0/0                  Current   Fast periodic           Attached
    LACP info:        Role     System             System       Port     Port    Port 
                             priority         identifier   priority   number     key 
      ge-0/0/0       Actor        127  d8:53:9a:56:53:20        127        1       1
      ge-0/0/0     Partner        127  68:22:8e:64:fa:40        127        2       1

     
  3. Restore et-0/0/50+et-0/0/51, then AE0/ICCP restores
  4. ae interface up/down timestamp, traffic should have no impacted as ae1 did not flap in QFX5110-1 
    labroot@QFX5110-1> show log messages | match SNMP_TRAP_LINK | match ae0 
Sep 12 16:00:59
Sep 12 15:57:48  QFX5110-1 mib2d[11099]: SNMP_TRAP_LINK_DOWN: ifIndex 4147, ifAdminStatus up(1), ifOperStatus down(2), ifName ae0
Sep 12 15:59:48  QFX5110-1 mib2d[11099]: SNMP_TRAP_LINK_UP: ifIndex 4147, ifAdminStatus up(1), ifOperStatus up(1), ifName ae0
 
#QFX5110-1 No flapping in ae1 
labroot@QFX5110-1> show log messages | match SNMP_TRAP_LINK | match ae1$ 
Sep 12 16:00:59
 
#QFX5110-2 ae1 down when ae0 down and coming back up when ae0+ICCP restore.
labroot@QFX5110-2> show log messages | match SNMP_TRAP_LINK | match ae1$ 
Sep 12 16:01:10
Sep 12 15:57:49  QFX5110-2 mib2d[9502]: SNMP_TRAP_LINK_DOWN: ifIndex 4144, ifAdminStatus up(1), ifOperStatus down(2), ifName ae1
Sep 12 16:00:07  QFX5110-2 mib2d[9502]: SNMP_TRAP_LINK_UP: ifIndex 4144, ifAdminStatus up(1), ifOperStatus up(1), ifName ae1

     

Modification History

2024-10-09 : Article Created