LACP shared with multiple vap-groups in VRRP configuration

Products

• XOS

Issue/Introduction

LACP shared between multiple VAP groups might trigger a VRRP failover if the LACP master VAP is reloaded 

vap-group fw xslinux_v5_64
vap-group fw2 xslinux_v5_64

circuit inside circuit-id 1032
  vap-group fw
    ip X.X.X.X z.z.z.z
  vap-group fw2
    ip y.y.y.y z.z.z.z

group-interface MLT1
  interface-type ethernet
  mode multi-link circuit inside
  interface 1/1
  interface 1/4
  interface 1/5
  interface 1/6
  
vrrp failover-group fw failover-group-id 2
  priority 254
  monitor-group-interface MLT1
    priority-delta 20
   
vrrp failover-group fw2 failover-group-id 3
  priority 254
  monitor-group-interface MLT1
    priority-delta 20
   



 

Resolution

When the LACP interface is configured, the master VAP is used to send the LACP packets. If the LACP is shared between multiple VAP groups, the LACP master VAP is the master VAP of the VAP group with the lowest VAP group ID.

To find the VAP group ID run the following command from the CPM prompt:

#/usr/bin/psql -U guest running-config -c "SELECT vfpgroupid, vfpgroupname FROM vfpGroupTable"
[[email protected] admin]# /usr/bin/psql -U guest running-config -c "SELECT vfpgroupid, vfpgroupname FROM vfpGroupTable"
 vfpgroupid | vfpgroupname
------------+--------------
          1 | fw
          2 | fw2
(4 rows)

The VAP-group id appears in the left hand column

To find the master VAP run the following command:
# show ap-vap-mapping
Module  Slot  Status  VAP IP Address  VAP Group  Index  Master (true/false) 
AP3     5     Active  1.1.1.103       fw         1      false               
AP4     6     Active  1.1.1.105       fw2        1      false               
AP5     7     Active  1.1.1.104       fw         2      true                
AP9     11    Active  1.1.1.106       fw2        2      true                
(4 rows)


In this case fw is the VAP group with lowest ID and fw_2(AP5)is the LACP master VAP.

If AP5 is reloaded, then AP3 will become the master VAP for the VAP group fw and for the LACP interface. In this scenario, the priority delta of the group interface MLT1 will not decrease and the failover will not occur. 

If the VAP group fw is reloaded, then the priority delta of the group interface MLT1 will decrement by 20 in both failover groups until the LACP master VAP is available. This might cause an unexpected failover. 
 
# reload vap-group fw

# show vrrp detail-status
Execute "show vrrp detail-status-help" to see help for this command.

FG_ID  Status  Priority  Delta  Type  Component                                
    2  Master   234/254     0     vr  inside/10/0/0            
    2  Master   234/254   -20     mg  MLT1                     
    3  Master   234/254     0     vr  inside/11/0/0            
    3  Master   234/254   -20     mg  MLT1