EX Series Virtual Chassis Overview

 

Many Juniper Networks EX Series switches support the Virtual Chassis flexible, scaling switch solution. You can connect individual switches together to form one unit and manage the unit as a single chassis. Virtual Chassis ports (VCPs) connect switches (Virtual Chassis members) together to form a Virtual Chassis, and are responsible for passing all data and control traffic between members.

The following feature guides describe Virtual Chassis on different switches:

This topic applies to all EX Series Virtual Chassis except EX8200 and EX9200 Virtual Chassis.

This topic describes:

Benefits of Virtual Chassis

  • Simplified configuration and maintenance: Multiple devices can be managed as a single device.

  • Increased fault tolerance and high availability (HA): A Virtual Chassis can remain active and network traffic can be redirected to other member switches when a single member switch fails.

  • Simplified Layer 2 network topology that minimizes or eliminates the need for loop prevention protocols such as Spanning Tree Protocol (STP).

  • Flexible model for expanding your network: You can easily add Virtual Chassis members to increase the number of access ports on your network to support more servers, computers, phones, or other devices with minimal complications to the existing network topology and switch configuration.

Virtual Chassis Support on EX Series Switches

The following Virtual Chassis are supported on EX Series switches:

  • An EX2200 Virtual Chassis, composed of up to four EX2200 switches

  • An EX2300 Virtual Chassis, composed of up to four EX2300 switches or up to four EX2300 multigigabit model switches (EX2300-24MP, EX2300-48MP)

  • An EX3300 Virtual Chassis, composed of up to ten EX3300 switches

  • An EX3400 Virtual Chassis, composed of up to ten EX3400 switches

  • An EX4200 Virtual Chassis, composed of up to ten EX4200 switches

  • An EX4300 Virtual Chassis, composed of up to ten EX4300 switches, including multigigabit models (EX4300-48MP).

    Note

    An EX4300 Virtual Chassis operates as a non-mixed Virtual Chassis if it is composed of only EX4300 multigigabit model switches, or composed of any combination of any other EX4300 switches excluding the multigigabit models. An EX4300 Virtual Chassis operates as a mixed EX4300 Virtual Chassis if it is composed of EX4300 multigigabit model (EX4300-48MP) switches mixed with any other EX4300 model switches.

  • An EX4500 Virtual Chassis, composed of up to ten EX4500 switches

  • An EX4550 Virtual Chassis, composed of up to ten EX4550 switches

  • An EX4600 Virtual Chassis, composed of up to ten EX4600 switches.

  • A mixed EX4200 and EX4500 Virtual Chassis, a Virtual Chassis composed of up to ten total EX4200 and EX4500 switches

  • A mixed EX4200 and EX4550 Virtual Chassis, a Virtual Chassis composed of up to ten total EX4200 and EX4550 switches

  • A mixed EX4200, EX4500, and EX4550 Virtual Chassis, a Virtual Chassis composed of up to ten total EX4200, EX4500, and EX4550 switches

  • A mixed EX4300 and EX4600 Virtual Chassis, a Virtual Chassis composed of up to ten total EX4300 (excluding multigigabit models) and EX4600 switches.

  • A mixed EX4500 and EX4550 Virtual Chassis, a Virtual Chassis composed of up to ten total EX4500 and EX4550 switches

Table 1 lists the initial Junos OS release that supports each Virtual Chassis combination. “N/A” indicates the combination is not supported. Switches must be running the same version of Junos OS software to join a Virtual Chassis, although the images might be different on different types of switches when mixed hardware models are supported together in a Virtual Chassis.

Table 1: Minimum Junos OS Release by Virtual Chassis Connection Type

Switch

EX2200 Switch

EX2300 Switch

EX3300 Switch

EX3400 Switch

EX4200 Switch

EX4300 Switch

EX4500 Switch

EX4550 Switch

EX4600 Switch

EX2200 Switch

12.2R1

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

EX2300 Switch

N/A

15.1X53-

D50, or 18.1R2

for MP

models

N/A

N/A

N/A

N/A

N/A

N/A

N/A

EX3300 Switch

N/A

N/A

11.3R1

N/A

N/A

N/A

N/A

N/A

N/A

EX3400 Switch

N/A

N/A

N/A

15.1X53-

D50

N/A

N/A

N/A

N/A

N/A

EX4200 Switch

N/A

N/A

N/A

N/A

9.0R1

N/A

11.1R1

12.2R1

N/A

EX4300 Switch

N/A

N/A

N/A

N/A

N/A

13.2X50-

D10, or 18.2R1

for MP

models

N/A

N/A

13.2X51-

D25, excludes EX4300 MP models

EX4500 Switch

N/A

N/A

N/A

N/A

11.1R1

N/A

11.1R1

12.2R1

N/A

EX4550 Switch

N/A

N/A

N/A

N/A

12.2R1

N/A

12.2R1

12.2R1

N/A

EX4600 switch

N/A

N/A

N/A

N/A

N/A

13.2X51-

D25, excludes EX4300 MP models

N/A

N/A

13.2X51-

D25

Basic Configuration of a Virtual Chassis

You can interconnect two or more switches to form a Virtual Chassis.

You can interconnect EX2200 switches into an EX2200 Virtual Chassis by configuring uplink ports as Virtual Chassis Ports (VCPs). You can configure any EX2200 uplink ports that support 1-Gbps speeds as VCPs.

You can interconnect EX2300 switches or EX2300 multigigabit switches into an EX2300 Virtual Chassis by configuring uplink ports as VCPs and using SFP+ transceivers.

Note

You cannot use SFP tranceivers on uplink ports to interconnect EX2300 switches into a Virtual Chassis.

You can interconnect EX3300 switches into a Virtual Chassis by interconnecting uplink port connections configured as VCPs between two or more switches. By default, uplink ports 2 and 3 on EX3300 switches are configured as VCPs. EX3300 switches do not have dedicated VCPs. See Configuring an EX3300 Virtual Chassis (CLI Procedure).

You can interconnect EX3400 switches into a Virtual Chassis using uplink port connections configured as VCPs between two or more switches. EX3400 switches do not have dedicated VCPs, but the QSFP+ uplink ports on EX3400 switches are configured as VCPs by default, or you can configure uplink ports with SFP+ tranceivers as VCPs.

You can interconnect EX4200, EX4500, and EX4550 switches in a Virtual Chassis by either interconnecting the switches through the dedicated VCPs or by configuring the optical port connections as VCPs. All EX4200 switches are shipped with two built-in dedicated VCPs. The dedicated VCPs are on the Virtual Chassis module in an EX4500 or EX4550 switch. All supported SFP, SFP+, and XFP uplink connections between EX4200, EX4500, and EX4550 switches can be configured as VCPs.

You can interconnect EX4300 switches into a Virtual Chassis. An EX4300 Virtual Chassis that has only multigigabit model (EX4300-48MP) switch members or has only any other EX4300 model switches (without multigigabit model members) is not a mixed EX4300 Virtual Chassis and you do not configure the Virtual Chassis into mixed mode. You can also combine EX4300 multigigabit model switches with other EX4300 model switches in a Virtual Chassis as a mixed mode EX4300 Virtual Chassis, which requires setting the Virtual Chassis into mixed mode. To include other EX4300 switches in a Virtual Chassis with EX4300 multigigabit models, you must configure the other EX4300 switches with a special configuration option (ieee-clause-82) when setting the switches into mixed mode. EX4300 multigigabit switches have four 40-Gbps QSFP+ ports on the rear panel that are dedicated VCPs, and no other ports can be configured into VCPs. On all other EX4300 switch models, all 40-Gbps QSFP+ ports on the switch are configured as VCPs by default.

You can interconnect EX4600 switches into a non-mixed EX4600 Virtual Chassis or a combination of EX4600 and EX4300 switches (excluding EX4300 multigigabit models) into a mixed EX4600 Virtual Chassis using the uplink ports on both types of switches. All uplink ports on EX4600 switches are not configured into VCPs by default, and must be explicitly configured. The 40-Gbps QSFP+ ports on an EX4300 switch are configured as VCPs by default, and can be used as VCPs without any additional configuration.

See the following for more information on configuring EX Series Virtual Chassis:

Expanding Configurations—Within a Single Wiring Closet and Across Wiring Closets

Within a single wiring closet, you can add a new member switch to a Virtual Chassis by cabling the member switch into the Virtual Chassis using dedicated VCPs for EX4200, EX4500, EX4550, and EX4300 multigigabit model (EX4300-48MP) switches, or default-configured VCPs for switches such as EX3300, EX3400, and other EX4300 switches, or any network or uplink ports that can be configured into VCPs on switches that do not support dedicated or default-configured VCPs.

You can easily expand a Virtual Chassis configuration beyond a single wiring closet or over a longer distance by connecting member switches together using SFP, SFP+, or XFP uplink ports that are supported as VCPs. All supported SFP, SFP+, or XFP uplink ports on EX4200, EX4500, and EX4550 switches can be configured as VCPs. All supported SFP+ and QSFP+ uplink ports on EX4300 and EX4600 switches can also be configured into VCPs.

EX2200, EX2300, EX3300, and EX3400 switches do not have dedicated VCPs. You must always use the uplink ports on an EX2200, EX2300, EX3300, or EX3400 switch to connect the Virtual Chassis both within a wiring closet and across wiring closets. Uplink ports 2 and 3 are configured by default as VCPs on EX3300 switches. All QSFP+ ports on EX3400 switches and all 40-Gbps QSFP+ ports on EX4300 switches (excluding multigigabit models) are configured as VCPs by default. No uplink ports on EX2200 or EX2300 switches are configured as VCPs by default; you can configure SFP ports on EX2200 switches and SFP+ ports on EX2300s as VCPs.

When you are creating a Virtual Chassis, you might want to deterministically control the role and member ID assigned to each member switch. You can do this by creating a preprovisioned configuration. You can add switches to a preprovisioned configuration by using the automatic VCP conversion feature (see Automatic Virtual Chassis Port (VCP) Conversion) to automatically configure the uplink ports as VCPs on the switches being added.

For procedures on adding a new switch to a wiring closet, see:

To manually configure a VCP, see:

Global Management of Member Switches in a Virtual Chassis

The interconnected member switches in a Virtual Chassis operate as a single network entity. You run EZSetup only once to specify the identification parameters for the master, and these parameters implicitly apply to all members of the Virtual Chassis. You can view the Virtual Chassis as a single device in the J-Web user interface (on platforms and software that support J-Web) and apply various device management functions to all members of the Virtual Chassis.

The serial console port and dedicated out-of-band management port that are on the rear panel of the individual switches have global virtual counterparts when the switches are interconnected in a Virtual Chassis configuration. A PC or laptop allows you to connect to the master switch by connecting a terminal directly to the console port of any member switch. A virtual management Ethernet (VME) interface allows you to remotely manage the Virtual Chassis configuration by connecting to the out-of-band management port of any member switch through a single IP address. See Understanding Global Management of a Virtual Chassis.

High Availability Through Redundant Routing Engines

You increase your network’s high availability when you interconnect an EX Series switch into a Virtual Chassis. A Virtual Chassis is more fault tolerant then a standalone EX series switch because it remains up when a single member switch fails, and provides sub-second convergence in the case of a device or link failure.

A Virtual Chassis has dual Routing Engines, with one switch in the master role and one switch in the backup role, and therefore supports many high availability features not supported on standalone EX Series switches, such as Graceful Routing Engine Switchover (GRES) for hitless failover. See Understanding High Availability on an EX Series Virtual Chassis for more information on high availability features in a Virtual Chassis.

You can further improve the high availability of your network by configuring the high availability features available for your EX Series Virtual Chassis. You can, for instance, configure Link Aggregation Groups (LAG) bundles to include member links on multiple member switches in the same Virtual Chassis. This configuration increases fault tolerance because traffic traversing the LAG can be redirected to an active member switch when a single member switch fails.

Adaptability as an Access Switch or Distribution Switch

A Virtual Chassis configuration supports a variety of user environments, because it can be composed of different models of switches. You can select different switch models to support various functions. For example, you might set up one Virtual Chassis access switch configuration composed of the full Power over Ethernet (PoE) models to support users sitting in cubicles equipped with PCs and Voice over IP (VoIP) phones. You could set up another Virtual Chassis configuration with partial PoE models to support the company's internal servers and configure one more Virtual Chassis configuration with partial PoE models to support the company's external servers. Alternatively, you can use the Virtual Chassis as a distribution switch.