Understanding EX9200 Virtual Chassis
We do not recommend using EX9200 switches in a Virtual Chassis, and support for that architecture was phased out as of Junos OS Release 17.1R1. For deployments with EX9200 switches, we recommend planning or moving to MC-LAG or Junos Fusion Enterprise architectures instead of using a Virtual Chassis.
EX9200 Virtual Chassis brings the Virtual Chassis flexible, scaling switch solution to Juniper Networks EX9200 Ethernet Switches. You can connect two EX9200 switches into an EX9200 Virtual Chassis and manage the interconnected switches as a single chassis. The advantages of connecting multiple switches into a Virtual Chassis include better-managed bandwidth at a network layer, simplified configuration and maintenance because multiple devices can be managed as a single device, increased fault tolerance and high availability (HA) because a Virtual Chassis can remain active and network traffic can be redirected to other member switches when a single member switch fails, and a flatter, simplified Layer 2 network topology that minimizes or eliminates the need for loop prevention protocols such as Spanning Tree Protocol (STP).
Starting with Junos OS Release 17.1R1, EX9200 switches support EX9200-RE2 module. You cannot form a Virtual Chassis using an EX9200 switch with an EX9200-RE2 module installed in it. If inadvertently configured as a Virtual Chassis, the device will not start up properly; use the request virtual-chassis member-id delete <force> command to remove the Virtual Chassis setting.
You configure an EX9200 Virtual Chassis by configuring optical interfaces into Virtual Chassis ports (VCPs). VCPs connect switches together to form a Virtual Chassis, and are responsible for passing all data and control traffic between member switches in the Virtual Chassis.
You can increase VCP bandwidth between member switches by configuring multiple interfaces between the same two switches into VCPs. When multiple VCPs are interconnecting the same two member switches, a link aggregation group (LAG) bundle is automatically formed when the VCPs are on interfaces supporting identical speeds. For instance, if you have two 10-Gigabit SFP+ interfaces configured as VCPs between member switches, a LAG with two member links with 20 Gbps of total bandwidth is formed.
An EX9200 Virtual Chassis can be composed of any two EX9200 switches. Both EX9200 switches must have dual Routing Engines installed, and all Routing Engines must be running the same version of Junos OS. All combinations of EX9204, EX9208, and EX9214 switches can be interconnected to form a Virtual Chassis.