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QFX5110-VC and QFX5110-VCF - Rebooting or removing and reinserting the VCP cables can result in Inter-member traffic flow issues

  [TSB17317] Show Article Properties


Alert Type:
PSN - Product Support Notification
Product Affected:
QFX5110-VC, QFX5110-VCF
Alert Description:

Inter-member traffic flow can break on a QFX5110-VC, and QFX5110-VCF, when doing one of the following actions:

  • Rebooting the VC or VCF
  • Removing and reinserting the VCP cables
Solution:
PROBLEM:

On issuing a reboot on a QFX5110-VC or a QFX5110-VCF, or when removing and then reinserting the VCP cables, SDK gets into an incorrect 'modportsetting. 
This breaks traffic flow between certain members of the QFX5110-VC or QFX5110-VCF. Once either the QFX5110-VC or QFX5110-VCF has re-converged after the reboot, or after reinserting the cables, the virtual chassis VCP (virtual chassis ports) ports stop forwarding traffic received on the local member to a different member.
  • This issue might affect traffic between certain VC/VCF members and not between all members.
  • It does not affect traffic traversing a standalone QFX5110, or traffic ingressing, and egressing the VC/VCF via the same member.
SOLUTION:

PR1350716    -    The issue is fixed for both the VC and VCF starting in JunOS 17.3R2-S2, 17.3R3 and 17.4R2 onwards in the respective release branches.
 
  • ​​QFX5110-VC and QFX5110-VCF   Fixed in JunOS Software 17.3R2-S2, 17.3R3, 17.4R2

WORKAROUND:
  • The workaround to resume inter-member traffic flow is to delete and re-configure the VC ports on the VC/VCF members between which traffic forwarding is broken.

PROCEDURE:
 ​1. Delete and re-configure the VC port on  either of the affected members like member 0 here:
 
root@dc-core-1> show virtual-chassis vc-port                                  
fpc0:
--------------------------------------------------------------------------
Interface   Type              Trunk  Status       Speed        Neighbor
or                             ID                 (mbps)       ID  Interface
PIC / Port
0/1         Configured         -1    Up           40000        1   vcp-255/0/48
0/2         Configured         -1    Up           40000        2   vcp-255/0/2
 
root@dc-core-1> request virtual-chassis vc-port delete pic-slot 0 port 1 member 0     
         
fpc0:
--------------------------------------------------------------------------
Port deletion initiated, use cmd show virtual-chassis vc-port to verify
 
 
root@dc-core-1> request virtual-chassis vc-port set pic-slot 0 port 1 member 0
     
fpc0:
--------------------------------------------------------------------------
Port conversion initiated,  use show virtual-chassis vc-port to verify
 
 
Interface: xe-1/0/46, Enabled, Link is Up
Encapsulation: Ethernet, Speed: 10000mbps
Traffic statistics:                                              Current delta
  Input bytes:              157167044416 (761999176 bps)           [413185728]
  Output bytes:              19848576069 (762000752 bps)           [373571840]
  Input packets:              2455735062 (1488283 pps)               [6480497]
  Output packets:              310133751 (1488282 pps)               [5837059] >>>>>>>>>Traffic flow recovered
Error statistics:
  Input errors:                        0                                   [0]
  Input drops:                         0                                   [0]
  Input framing errors:                0                                   [0]
  Policed discards:                    0                                   [0]
  L3 incompletes:                      0                                   [0]
  L2 channel errors:                   0                                   [0]
  L2 mismatch timeouts:                0  Carrier transitions:             [0] 
Implementation:
OBSERVATIONS:

root@dc-core-1> show virtual-chassis 
 
Preprovisioned Virtual Chassis
Virtual Chassis ID: 8be6.8763.4c4c
Virtual Chassis Mode: Enabled
                                                Mstr           Mixed Route Neighbor List
Member ID  Status   Serial No    Model          prio  Role      Mode  Mode ID  Interface
0 (FPC 0)  Prsnt    WT3717060014 qfx5110-32q    129   Backup       N  VC   1  vcp-255/0/1
                                                                           2  vcp-255/0/2
1 (FPC 1)  Prsnt    WS3717190092 qfx5110-48s-4c   0   Linecard     N  VC   0  vcp-255/0/48
                                                                           2  vcp-255/0/50
2 (FPC 2)  Prsnt    WT3717190092 qfx5110-32q    129   Master*      N  VC   1  vcp-255/0/1
                                                                           0  vcp-255/0/2
 
                             
+---------------------------+xe-0/0/5:0
|         QFX5110VC     |
| FPC0                        +----------------------> jtac-Traffic_Generator-SPT-N11U-r001(3/1)
|                                  |
+---------------------------+
|                                   |xe-1/0/46
| FPC1                       +---------------------->jtac-Traffic_Generator-SPT-N11U-r001(1/1)
+---------------------------+
|                                  |xe-2/0/5:0
| FPC2                        +---------------------->jtac-Traffic_Generator-N11U-r003(5/3)
+---------------------------+
 
 
 
 
The following traffic streams have been set up for testing:
 
1.  Traffic from member1 to member2: jtac-Traffic_Generator-SPT-N11U-r001 (1/1)--->jtac-Traffic_Generator-SPT-N11U-r003 (5/3)
2.  Traffic from member0 to member1: jtac-Traffic_Generator-SPT-N11U-r001 (3/1)--->jtac-Traffic_Generator-SPT-N11U-r001 (1/1)
3.  Traffic from member2 to member0: jtac-Traffic_Generator-SPT-N11U-r003 (5/3)--->jtac-Traffic_Generator-SPT-N11U-r001 (3/1)
 
TRIGGER:
 
   Reboot the QFX5110-VC.
 
   root@dc-core-1> request system reboot all-members
 
 
IMPACT OBSERVED:
 
 
1. In this case, we observed that traffic from member 0 to member 1  and traffic between 2 and 0 would be broken.
2. Traffic between Member 1 to Member 2 is not impacted.
   
The following is a snippet of the impact on traffic from member 0 to member 1.
 
Interface: xe-0/0/5:0, Enabled, Link is Up
Encapsulation: Ethernet, Speed: 10000mbps
Traffic statistics:                                              Current delta
  Input bytes:              122516383744 (762121024 bps)         [41368660864]
  Output bytes:                 79779942 (304 bps)                     [19680]
  Input packets:              1914318487 (1488516 pps)             [646409604]>>>>> Traffic to be forwarded to member1
  Output packets:                1246372 (0 pps)                         [243]
Error statistics:
  Input errors:                        0                                   [0]
  Input drops:                         0                                   [0]
  Input framing errors:                0                                   [0]
  Policed discards:                    0                                   [0]
  L3 incompletes:                      0                                   [0]
  L2 channel errors:                   0                                   [0]
  L2 mismatch timeouts:                0  Carrier transitions:             [0]
 
 
 
 
root@fpc0>monitor interface traffic                
 
Interface    Link  Input packets        (pps)     Output packets        (pps)
 vcp-255/0/1   Up            985          (0)          9937819          (0)  >>>>> No traffic is being forwarded out by
 vcp-255/0/2   Up       24931717         (36)          9961997          (0)        vcp-255/0/1 to member1 
 gr-0/0/0      Up              0          (0)                0          (0)
 et-3/0/0    Down              0          (0)                0          (0)
 pfh-3/0/0     Up              0                             0
 xe-3/0/5:0    Up              0          (0)                0          (0)
 xe-3/0/5:1  Down              0          (0)                0          (0)
 xe-3/0/5:2  Down              0          (0)                0          (0)
 xe-3/0/5:3  Down
 
 
 
 
 
Interface: xe-1/0/46, Enabled, Link is Up
Encapsulation: Ethernet, Speed: 10000mbps
Traffic statistics:                                              Current delta
  Input bytes:               77574200704 (761846160 bps)                   [0]
  Output bytes:                 34939942 (304 bps)                         [0]
  Input packets:              1212072513 (1487981 pps)                     [0]
  Output packets:                 545816 (0 pps)                           [0] >>>> No traffic forwarded out of this port
Error statistics:
  Input errors:                        0                                   [0]
  Input drops:                         0                                   [0]
  Input framing errors:                0                                   [0]
  Policed discards:                    0                                   [0]
  L3 incompletes:                      0                                   [0]
  L2 channel errors:                   0                                   [0]
  L2 mismatch timeouts:                0  Carrier transitions:             [0]
Modification History:

 
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