Configure a Virtual Chassis Using EX3400, EX4100, EX4100-F, EX4100-H, EX4300, EX4000, or EX4400

Follow these steps to configure a Virtual Chassis on Juniper switches with a dedicated Virtual Chassis port.

Note:

Instructions for configuring a Virtual Chassis using the EX4400-24X switches are slightly different. For details, refer to Configure a Virtual Chassis Using EX4400-24X.
Ensure that you use the Mist portal interfaces to manage all Virtual Chassis configurations. Avoid using CLIs or Additional CLIs for managing Virtual Chassis settings.
Juniper Mist automatically upgrades a Virtual Chassis linecard member if it is running a Junos version different from that of the primary member. The linecard member will be upgraded to the same version as the primary member if the following conditions are met:
- The switch must form a Virtual Chassis with three or more members—that is, a primary, a backup, and a linecard member.
- The Junos version on the linecard member is different from that on the primary member.
- The linecard member must be in Inactive state.
  
  Note that a linecard member will be upgraded only if it is inactive and running a clearly different Junos version. Minor differences, such as different spin numbers, will not trigger an upgrade.
- Only the Junos versions listed on the Mist portal are available for upgrade.

The EX3400, EX4100, EX4100-F, EX4100-H, EX4300, EX4000, and EX4400 switches come with dedicated Virtual Chassis ports (VCPs). To create Virtual Chassis using these switches, you only need to connect them to each other via VCPs. The Form Virtual Chassis option on the Switches page on the Mist portal is not applicable to these switches. However, once a Virtual Chassis is created with these switches, you can use the Modify Virtual Chassis option on the switch details page to modify and manage the Virtual Chassis. The Virtual Chassis workflow for these switches involves the following two steps:

Virtual Chassis formation by connecting the switches via the dedicated VCPs and powering on them.
Preprovisioning the Virtual Chassis using the Modify Virtual Chassis option on the Juniper Mist Portal. Mist supports only the preprovisioned Virtual Chassis configuration. The preprovisioned configuration specifies the chassis serial number, member ID, and role for both member switches in the Virtual Chassis. When a new member router joins the Virtual Chassis, Junos compares its serial number against the values specified in the preprovisioned configuration. Preprovisioning prevents any accidental role assignments, or the accidental addition of a new member to the Virtual Chassis. Each role, member ID, addition or removal of members, is under the control of the configuration.

In addition to Virtual Chassis creation, you can renumber, replace, or add a member to an existing Virtual Chassis, by using the Modify Virtual Chassis option on the Switch Details Page.

You can configure the Virtual Chassis in mixed mode or non-mixed mode. A Virtual Chassis that includes switches of the same model operates as a non-mixed Virtual Chassis. However, a Virtual Chassis that includes different models of the same switch operates in mixed mode because of architecture differences between the different switch models. For more information, see Mixed and Non-Mixed Virtual Chassis.

Table 1: Supported Combination of Switches in a Mixed-Mode Virtual Chassis
Allowed Routing Engine Members	Allowed Linecard Members
EX4300	EX4300
EX4300-48MP	EX4300-48MP and EX4300

To configure a Virtual Chassis using EX3400, EX4100, EX4100-F, EX4300, or EX4400 switches:

Ensure that all the switches that you want to include in the Virtual Chassis are onboarded to the Juniper Mist cloud and assigned to the same site. To onboard a new switch (greenfield deployment), see Onboard Switches to Mist Cloud. To onboard an existing switch (brownfield deployment), see Onboard a Brownfield Switch.
Power off the switches that you want to include in the Virtual Chassis.
Connect the switches to each other using the dedicated Virtual Chassis ports (VCPs), preferably in a full ring topology, as shown below. The following is a sample image. The location of the VCPs will vary depending on the switch models.

Note:
On EX4100-F-12P and EX4100-F-12T switches, the 10-Gigabit Ethernet ports in PIC 2, which are used as uplink ports, cannot be configured as Virtual Chassis ports. These ports do not support the HGoE mode. For more information about the HGoE mode, see HiGig and HGoE Modes.
Power on the switches.
Wait for the MST LED on the primary and backup switches to come up. The LED appears solid on the primary switch. On the backup switch, the LED stays in a blinking state.

Note: MST LED remains Off on the switches elected as the Linecard members in a Virtual Chassis.

A Virtual Chassis is now physically formed but not preprovisioned.
Connect the Virtual Chassis to the Juniper Mist cloud by connecting the uplink port on the primary switch to the upstream switch.

We recommend connecting the uplink port only after the Virtual Chassis has formed. Wait for the MST LEDs to come up (LED appears solid on the primary member and blinking on the backup member), then connect the uplink ports on those members.

This step initiates a zero-touch provisioning (ZTP) process on the Virtual Chassis and connects it to the Juniper Mist cloud.
After a Virtual Chassis connects to the Mist cloud for the first time, it may take 5 to 10 minutes for the Virtual Chassis stats to appear on the Mist cloud for all the members.
Click Switches > Switch Name to go to the Virtual Chassis page (the switch details page) to verify the details.

The switches appear as a single Virtual Chassis as shown below:
After Virtual Chassis is connected to the Mist cloud, preprovision it. Preprovisioning allows users to define the roles and renumber appropriately. To preprovision the Virtual Chassis, follow the steps below:
1. On the switch details page, click Modify Virtual Chassis.
  
  The Modify Virtual Chassis page appears.
  
  Note: The Modify Virtual Chassis option is available for switches that have the configuration management enabled in Mist.
2. On the Modify Virtual Chassis page, click Preprovision Virtual Chassis.
  
  This step pushes the preprovisioned Virtual Chassis configuration to the device and overwrites the old autoprovision Virtual Chassis configuration pushed to the device during the ZTP process. This option assumes the current positioning of the members and preprovisions them as is.
Note:
If you make any changes on the Modify Virtual Chassis page, such as moving the members around or adding or removing members, the Preprovision Virtual Chassis button is disabled and the Update button is enabled. In this case, click the Update button to effect the changes made and Preprovision the Virtual Chassis.

All configurations are pushed instantly after you preprovision the Virtual Chassis. The stats could take up to 15 minutes to appear on the Mist dashboard.

For a detailed procedure on how to modify a Virtual Chassis, see Manage a Virtual Chassis Using Mist.