VC ports using 100GBASE-BXSR optic does not come up in 2 member virtual-chassis of QFX5120-48Y.

VC ports will be down if:

• We are using 100GBASE-BXSR SFP
• We Converted the QSFP28 ports (48 through 55) into VC ports

100GBASE-BXSR optic is supported on QFX5120-48Y platform however it is not qualified by team to be used as a VC port. Instead use SFP+40GE-LX4.

Scenario-1: Using 100GBASE-BXSR SFP for VC connectivity to form 2 member virtual-chassis and it is not successful.
                   

• Verify the hardware status of both the SFPs on both the devices

user@switch> show chassis hardware | no-more 
Hardware inventory:
Item       Version Part number Serial number   Description
Routing Engine 0     BUILTIN   BUILTIN      RE-QFX5120-48Y-8C
FPC 0      REV 15  650-083242  abc123   JNP48Y8C-CHAS
 CPU           BUILTIN   BUILTIN      FPC CPU
 PIC 0          BUILTIN   BUILTIN      48x25G-8x100G
  Xcvr 50   REV 01  740-080491  XXXXXXXX 100GBASE-BXSR
  Xcvr 51   REV 01  740-080491  YYYYYYYYY   100GBASE-BXSR
 

• Verify the status of the port on both the devices

user@switch> show interfaces terse | match et-0/0/5
Interface        Admin Link Proto  Local         Remote
et-0/0/50        up  up
et-0/0/50.16386     up  up  
et-0/0/51        up  up
et-0/0/51.16386     up  up  
 

• Converted the ports et-0/0/50 and et-0/0/51 into VC ports on both the devices

user@switch> request virtual-chassis vc-port set pic-slot 0 port 50 
user@switch> request virtual-chassis vc-port set pic-slot 0 port 51
 

• Verify VC port status on both the devices

user@switch> show virtual-chassis vc-port
localre:
--------------------------------------------------------------------------
Interface  Type       Trunk Status    Speed    Neighbor
or               ID         (mbps)    ID Interface
PIC / Port
0/50    Configured     -1  Down     100000
0/51    Configured     -1  Down     100000


Scenario-2: Used QSFP+40GE-LX4 SFP for VC connectivity to form 2 member virtual-chassis and it is successful.

• Verify the hardware status of both the SFPs on both the devices

user@switch> show chassis hardware | no-more 
Hardware inventory:
Item       Version Part number Serial number   Description
Routing Engine 0     BUILTIN   BUILTIN      RE-QFX5120-48Y-8C
FPC 0      REV 15  650-083242  cba123   JNP48Y8C-CHAS
 CPU           BUILTIN   BUILTIN      FPC CPU
 PIC 0          BUILTIN   BUILTIN      48x25G-8x100G
 Xcvr 50   REV 01  740-080491  XXXXXXXX   100GBASE-BXSR
 Xcvr 51   REV 01  740-080491  YYYYYYYYY   100GBASE-BXSR

• Verify the status of the port on both the devices

user@switch show interfaces terse | match et-0/0/5
Interface        Admin Link Proto  Local         Remote
et-0/0/50        up  up
et-0/0/50.16386     up  up  
et-0/0/51        up  up
et-0/0/51.16386     up  up  
 

• Converted the ports et-0/0/50 and et-0/0/51 into VC ports on both the devices

root@switch> request virtual-chassis vc-port set pic-slot 0 port 50 
root@switch> request virtual-chassis vc-port set pic-slot 0 port 51

• Verify the VC-port status

user@switch show virtual-chassis vc-port
localre:
--------------------------------------------------------------------------
Interface   Type              Trunk  Status       Speed        Neighbor
or                             ID                 (mbps)       ID  Interface
PIC / Port
0/50        Configured          5    Up           40000        1   vcp-255/0/50
0/51        Configured          5    Up           40000        1   vcp-255/0/51

fpc1:
--------------------------------------------------------------------------
Interface   Type              Trunk  Status       Speed        Neighbor
or                             ID                 (mbps)       ID  Interface
PIC / Port
0/50        Configured          5    Up           40000        0   vcp-255/0/50
0/51        Configured          5    Up           40000        0   vcp-255/0/51
 

• Verify VC status

user@switch> show virtual-chassis status
Virtual Chassis ID: 14fc.92fe.95d2
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    abc123           qfx5120-48y-8c 128   Master*      N    VC           1         vcp-255/0/50
                                                                                                                                      1         vcp-255/0/51
1 (FPC 1)    Prsnt    cba123           qfx5120-48y-8c 128   Backup       N   VC            0         vcp-255/0/50
                                                                                                                                      0          vcp-255/0/51