Virtual Chassis

Using Virtual Chassis

Juniper recommends using Virtual Chassis (VC). With VC, you can combine multiple EX switches so they act as a single device with regards to the Juniper Mist cloud. This eliminates the risk of loops, the need for legacy redundancy protocols such as spanning tree and VRRP, and the time required for individual device management. In core/distribution deployments, you can connect to the VC using link aggregation group (LAG) uplinks, which then has the additional benefit of the member switches providing device-level redundancy for the link in case of device failure.

A Typical Virtual Chassis Setup.

A Virtual Chassis can include from two to ten switches, with each member switch having however many ports. Such as physical configuration can provide better resilience in case one member switch goes down; there are simply more surviving switches available to take up the redistributed load. The trade-off, though, is that those switches require both space and power.

VC for the Juniper Mist cloud is supported for the switches show in (the switch model is accompanied by the maximum number of members allowed in the VC

Cloud-Ready EX Switches

Design Considerations for Virtual Chassis

We recommend that you physically distribute your Juniper APs across a floor in the network operations center (NOC) so that they connect to multiple switches in a virtual stack. Doing so provides better redundancy and is a more robust design for handling power-supply related hardware failure.

Virtual Chassis Setup in a NOC

For example, let’s say you want to deploy a solution that includes 96 ports. The two main options for doing so are:

  • Use two EX4300-48P switches, with one switch serving as primary and one as backup. The advantages here are, a compact footprint and cost effectiveness. The primary disadvantage is that the loss of one switch can impact 50 percent of your users.
  • Use four EX4300-24P switches, with one switch serving as primary, one as backup, and two switches serving as line cards. The advantages here are, higher availability (the loss of one switch only affects 25 percent of users), and the fact that uplinks are not affected by a switch failure (provided that the failed switch did not include any uplinks). The primary disadvantage is that you need more space, power, and cost so support the equipment.

Regardless of the options you go with, if you do plan to leverage one or more Virtual Chassis in your deployment, we recommend that you configure the primary and backup switches in the Virtual Chassis so that they are in different physical locations in the NOC. The member devices of the Virtual Chassis should be likewise distributed so that no more than half are dependent on the same power supply or other single point of failure, and they should be evenly spaced by a member hop in the Virtual Chassis.

 

Setting up Virtual Chassis on EX2300 Switches in the Juniper Mist Cloud

Switches in a VC must all be the same model and running the same version of Junos, which must also be a Juniper Mist compatible release. You will need physical access to the switches for cabling, and management access to both the CLI and Juniper Mist cloud.

Virtual Chassis for EX2300.

In the process described below, you start with a switch that has already been provisioned for Juniper Mist and is available from the Juniper Mist portal. Then you log on to the switch using the Juniper Mist portal and configure its VC interfaces. From there, you make the physical connection from that switch to the next one in the VC group, propagate the relevant settings, and repeat until all the VC members are connected. The last step is then to synchronize the VC configuration across member switches.

Virtual Chassis Connections for EX2300.
  1. Power on each EX Switch, but do not connect any Ethernet or VC cables yet.
  2. Physically connect the switch with Juniper Mist access to the internet using either a management or revenue port. The switch will automatically receive Zero Touch updates from the cloud, including the DNS settings it will need. In the Juniper Mist portal, the switch should be visible, and with a green status.
  3. Access the switch from the Juniper Mist portal using the CLI shell, and enter run the following commands to enable VC Ports on the switch:

  4. Verify that the ports were successfully configured by running this command:
     
  5. Back at the switches, connect a VC cable from the ports you just enable to the next switch and confirm that the LEDs on the VC ports are active.
  6. From the Juniper CLI shell, run the following command to confirm that the newly added switch is present:
  7. Repeat steps 2-7 until all switches have been added to VC and then connect the VC port redundancy cable.
  8. When you are done, the switch will be added to the Juniper Mist cloud, and you can see it from the Switches screen as shown in Figure 4.

 

Setting up Virtual Chassis on EX3400 and EX4300 Switches in the Juniper Mist Cloud

Switches in a VC must all be Juniper Mist cloud-ready. You will need physical access to the switches for cabling, and management access to both the CLI and Juniper Mist cloud.

Virtual Chassis for EX4300.
Virtual Chassis for EX3400.

 

Note that the second switch in the VC is automatically assigned the backup role, and its LED will blink when connected. All remaining switches automatically assume line-card roles, and their MST LEDs will remain dark.

In the process described below, you start with a switch that is available from the Juniper Mist portal. Then you log on to the switch using the Juniper Mist portal and configure its VC interfaces. From there, you make the physical connection from that switch to the next one in the VC group, propagate the relevant settings, and repeat until all the VC members are connected.

  1. Power on each EX Switch, but do not connect any Ethernet or VC cables yet. Wait until you see the MST LED is lit and not blinking on any of the switches.
  2. Physically connect the switch with Juniper Mist access to the internet using either a management or revenue port. The switch will automatically receive Zero Touch updates from the cloud, including the VC configuration. In the Juniper Mist portal, the switch should be visible, and with a green status.
  3. Access the switch from the Juniper Mist portal using the CLI shell, and run the following commands to verify that the VC ports were successfully configured (all the switches in the VC should be listed in the results):
     
  4. Back at the switches, connect a VC cable from to the next switch and confirm that the LED on the VC ports are active.
  5. Repeat steps 2-4 until all switches have been added to VC and then connect the VC port redundancy cable.
  6. When you are finished, the VC will be provisioned in the Juniper Mist cloud and the details of the EX cluster visible in the Juniper Mist portal, as shown below

 

When multiple switches are configured as a virtual chassis, they may be displayed in two different ways. Just select either All or click on the number to indicate which switch to look at.

All at once:

Individually: