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How to locate the serial number for a QFX3500 chassis



Article ID: KB31563 KB Last Updated: 05 Apr 2021Version: 2.0

For the QFX3500 platform, there may be a difference between the chassis serial number and the Flexible PIC Concentrator (FPC) serial number. The FPC serial number will be used to form a Virtual Chassis (VC)/Virtual Chassis Fabric (VCF).

In this case, after VC/VCF is formed, 'show chassis hardware' will display only FPC serial number, not the chassis serial number.


There are two SN format for QFX3500:

  1. Chassis SN with PXXXX and FPC SN with BBAKXXXX. This is mostly for older units ( REV 11 or earlier)
  2. Chassis SN with PXXXX and FPC SN with PXXXX-C. This is mostly for newer units. ( REV 15 or later)

The command, ‘show chassis hardware’ will display both the chassis AND the FPC serial numbers for standalone QFX3500.

root> show chassis hardware
Hardware inventory:
Item             Version  Part number  Serial number     Description
Chassis                                P0204             QFX3500
Pseudo CB 0
Routing Engine 0          BUILTIN      BUILTIN           QFX Routing Engine
FPC 0            REV 09   750-036931   BBAK8704          QFX3500-48S4Q
  CPU                     BUILTIN      BUILTIN           FPC CPU
  PIC 0                   BUILTIN      BUILTIN           48x 10G-SFP+
  PIC 1                   BUILTIN      BUILTIN           4x 40G-QSFP+
    Xcvr 0       REV 01   740-032986   QA460315          QSFP+-40G-SR4
    Xcvr 1       REV 01   740-032986   QA460318          QSFP+-40G-SR4
  MGMT BRD       REV 05   750-036946   BBAK8652          QFX3500-MGMT-RJ45-AFI
Power Supply 0
Power Supply 1
Fan Tray 0                                               QFX3500 Fan Tray, Front to Back Airflow
Fan Tray 1                                               QFX3500 Fan Tray, Front to Back Airflow
Fan Tray 2                                               QFX3500 Fan Tray, Front to Back Airflow

'show virtual-chassis' will display only the FPC serial number for standalone devices . This serial number will be used to form a VC/VCF in pre-provisioned mode.

root> show virtual-chassis
Virtual Chassis ID: 6986.2afe.b198
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    BBAK8704     qfx3500s       128   Master*      N  VC
virtual-chassis {
      member 0 {
           role routing-engine;
           serial-number BBAK8704;
      member 1 {
           role routing-engine;
           serila-number P2020;

root@boa-te-3500v> show virtual-chassis status

Preprovisioned Virtual Chassis
Virtual Chassis ID: 25f2.bb72.5ddb
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    BBAK8704     qfx3500s       129   Master*      N  VC   1  vcp-255/1/0  
                                                                           1  vcp-255/1/1
                                                                           1  vcp-255/1/2
                                                                           1  vcp-255/1/3
1 (FPC 1)  Prsnt    P2020-C      qfx3500s       129   Backup       N  VC   0  vcp-255/1/1
                               0  vcp-255/1/0
                                                                           0  vcp-255/1/2
                                                                           0  vcp-255/1/3

If the device has a different SN for the chassis, and the FPC is not primary in VC/VCF, 'show virtual-chassis status' and 'show chassis hardware' will display only the FPC serial number, not the chassis. serial number.


The following method can be used to retrieve chassis SN of individual FPC.

  1. Gather complete 'show chassis hardware extensive' from the primary RE of the VC/VCF system.
  2. Locate the hex value of chassis SN. (Address 0x74-0x78)
  3. Convert the hex value to ASCII. (can use online tools such as:

Example (Aunit from JTAC lab (Chassis SN:P0822 / FPC SN: BBAK1186):

 FPC 1            REV 11   750-036931   BBAK1186          QFX3500-48S4Q
 Jedec Code:   0x7fb0            EEPROM Version:    0x02
 P/N:          750-036931        S/N:               S/N BBAK1186
 Assembly ID:  0x09a5            Assembly Version:  02.11
 Date:         05-21-2011        Assembly Flags:    0x00
 Version:      REV 11            CLEI Code:         CMMFX00BRA
 ID: QFX3500-48S4Q               FRU Model Number:  QFX3500-48S4Q
 Board Information Record:
  Address 0x00: ad 01 01 04 84 18 88 d5 2c 24 ff ff ff ff ff ff
 I2C Hex Data:
  Address 0x00: 7f b0 02 ff 09 a5 02 0b 52 45 56 20 31 31 00 00
  Address 0x10: 00 00 00 00 37 35 30 2d 30 33 36 39 33 31 00 00
  Address 0x20: 53 2f 4e 20 42 42 41 4b 31 31 38 36 00 15 05 07
  Address 0x30: db ff ff ff ad 01 01 04 84 18 88 d5 2c 24 ff ff
  Address 0x40: ff ff ff ff 01 43 4d 4d 46 58 30 30 42 52 41 51
  Address 0x50: 46 58 33 35 30 30 2d 34 38 53 34 51 00 00 00 00
  Address 0x60: 00 00 00 00 00 00 42 00 00 ff ff ff ff ff ff ff
  Address 0x70: ff ff ff 11 50 30 38 32 32 00 00 00 00 00 00 00


  • Address 0x74-0x78 is "50 30 38 32 32"
  • Convert to ASCII is "P0822"


The 'show chassis hardware' command should be executed from primary only. If issued from other members, it will be incomplete.

Modification History:
2021-03-25: Updated the article terminology to align with Juniper's Inclusion & Diversity initiatives.
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