Description

This article describes an issue where a formatted EX4300/EX4600 Virtual Chassis member failed to rejoin the mixed Virtual Chassis after recovery. The issue was caused by the loss of the mixed-mode configuration during the format installation process. Re-enabling mixed mode allowed the member to successfully rejoin the Virtual Chassis and synchronize its configuration from the master Routing Engine.

Symptoms

user@switch> show virtual-chassis 
Preprovisioned Virtual Chassis
Virtual Chassis ID: abcd.ef00.1234
Virtual Chassis Mode: Mixed
                                            Mstr         Mixed Route Neighbor List
Member ID  Status   Serial No  Model        prio  Role   Mode  Mode  ID Interface
0 (FPC 0)  Prsnt    ...        ex4600       129   Master*    Y  VC   1  vcp-255/1/0
                                                                     3  vcp-255/1/3
1 (FPC 1)  NotPrsnt ...        ex4600       129   Backup     N  VC   0  vcp-255/1/1. --> Mixed mode was disabled.
                                                                     2  vcp-255/1/3
2 (FPC 2)  Prsnt    ...        ex4300-48t     0   Linecard   Y  VC   3  vcp-255/1/1
                                                                     1  vcp-255/1/3
3 (FPC 3)  Prsnt    ...        ex4300-48t     0   Linecard   Y  VC   0  vcp-255/1/0
                                                                     2  vcp-255/1/2

**********************************************************************************************************************

user@switch> show virtual-chassis Preprovisioned Virtual Chassis Virtual Chassis ID: abcd.ef00.1234 Virtual Chassis Mode: Mixed Mstr Mixed Route Neighbor List Member ID Status Serial No Model prio Role Mode Mode ID Interface 0 (FPC 0) Prsnt ... ex4600 129 Master* Y VC 1 vcp-255/1/0 3 vcp-255/1/3 1 (FPC 1) Inactive ... ex4600 129 Backup N VC 0 vcp-255/1/1 2 vcp-255/1/3 2 (FPC 2) Prsnt ... ex4300-48t 0 Linecard Y VC 3 vcp-255/1/1 1 vcp-255/1/3 3 (FPC 3) Prsnt ... ex4300-48t 0 Linecard Y VC 0 vcp-255/1/0 2 vcp-255/1/2

Solution

The affected device was part of a 4-member Virtual Chassis consisting of a mix of EX4300 and EX4600 platforms. One of the members was unable to recognize its hardware components and remained in an error state. As a recovery measure, a format installation was recommended.

Since the device was operating as a Virtual Chassis member, it was first isolated and converted to a standalone device before performing the format installation. It is important to note that a format installation removes the entire configuration from the device, including the Virtual Chassis mixed-mode configuration.

After the format installation was completed, the Virtual Chassis status was verified. It was observed that mixed mode was not enabled on the formatted member. As a result, the member was unable to stably rejoin the existing mixed-platform Virtual Chassis.

To resolve the issue, mixed mode was re-enabled on the affected member using the following command:

user@switch> request virtual-chassis mode mixed reboot member 1

After the reboot, the member successfully joined the Virtual Chassis. The configuration was automatically synchronized from the master Routing Engine, and the Virtual Chassis returned to a stable operational state without any further issues.

 

user@switch> show virtual-chassis 
Preprovisioned Virtual Chassis
Virtual Chassis ID: abcd.ef00.1234
Virtual Chassis Mode: Mixed
                                            Mstr         Mixed Route Neighbor List
Member ID  Status   Serial No  Model        prio  Role   Mode  Mode  ID Interface
0 (FPC 0)  Prsnt    ...        ex4600       129   Master*    Y  VC   1  vcp-255/1/0
                                                                     3  vcp-255/1/3
1 (FPC 1)  Prsnt    ...        ex4600       129   Backup     Y  VC   0  vcp-255/1/1
                                                                     2  vcp-255/1/3
2 (FPC 2)  Prsnt    ...        ex4300-48t     0   Linecard   Y  VC   3  vcp-255/1/1
                                                                     1  vcp-255/1/3
3 (FPC 3)  Prsnt    ...        ex4300-48t     0   Linecard   Y  VC   0  vcp-255/1/0
                                                                     2  vcp-255/1/2

Note: When  member in VC is formatted, make sure that the respective mode and VC ports were configured to avoid instabilities.



Modification History

2026-06-07 : Article Created