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Understanding QFX Series Virtual Chassis

Note:

If your Virtual Chassis is managed through Juniper Mist, you can configure and manage it through the Mist portal. To know more, see Virtual Chassis Overview (Mist).

This topic introduces QFX Series Virtual Chassis. A QFX Series Virtual Chassis is a supported combination of interconnected QFX5110, QFX5120 or EX4650, QFX5200, and EX4300 switches operating as one logical device and managed as a single chassis. Switches in a Virtual Chassis are called member switches of the Virtual Chassis.

Virtual Chassis Support on QFX Series Switches

A QFX Series Virtual Chassis is a flexible, scaling switch solution for supported combinations of QFX5110, QFX5120, and QFX5200 switches. EX4650-48Y switches operate the same as QFX5120-48Y switches in a Virtual Chassis, so QFX Series Virtual Chassis configuration, monitoring and maintenance steps also apply to EX4650 Virtual Chassis. EX4300 switches can be included in some configurations of a QFX Series Virtual Chassis.

In a QFX Series Virtual Chassis, you can interconnect standalone switches in the following combinations into one logical device, and manage the logical device as a single chassis:

  • Up to three QFX5200 switches (a non-mixed Virtual Chassis)

  • Two QFX5120 switches or up to four EX4650 switches (a non-mixed Virtual Chassis), as follows:

    • Starting in Junos OS Release 19.3R1, you can interconnect two QFX5120-48Y or EX4650-48Y switches into a Virtual Chassis.

    • Starting in Junos OS Release 20.1R1, you can interconnect up to four EX4650-48Y switches into a Virtual Chassis.

    • Starting in Junos OS Release 20.2R1, you can interconnect two QFX5120-48T switches into a Virtual Chassis.

    • Starting in Junos OS Release 20.3R1, you can interconnect two QFX5120-32C switches into a Virtual Chassis.

    • Starting in Junos OS Release 23.1R1, you can interconnect four QFX5120-48YM switches into a Virtual Chassis.

  • Up to ten QFX5110 switches or a combination of QFX5110 and QFX5100 switches (a non-mixed Virtual Chassis)

  • Up to ten QFX5100 switches with any combination of QFX3500, QFX3600, or EX4300 switches (a mixed-mode Virtual Chassis)

  • Up to ten QFX3500 or QFX3600 switches with supported EX4300 switches, or a combination of all three types of switches (a mixed-mode Virtual Chassis)

    Note:

    EX4300 multigigabit model (EX4300-48MP) switches are not supported in a mixed-mode Virtual Chassis with any QFX Series switches. Also note that the JNP-QSFP-100G-BXSR transceiver is not supported on Virtual Chassis Ports (VCP) connections.

Basic Configuration of QFX Series Virtual Chassis

Some QFX Series switches can only form a Virtual Chassis with the same type of switches, while others can be interconnected with other types of switches into a mixed-mode Virtual Chassis. See Understanding Mixed EX Series and QFX Series Virtual Chassis for details on the different types of switches that can be mixed in a Virtual Chassis.

You set up a Virtual Chassis by configuring Virtual Chassis ports (VCPs) on the member switches, and interconnecting the switches using the VCPs . VCPs are responsible for passing all data and control traffic between member switches in the Virtual Chassis.

The following ports on QFX Series switches that support Virtual Chassis can be configured into VCPs to form a QFX Series Virtual Chassis:

  • On QFX5200 switches: Any 40-Gigabit Ethernet QSFP+ ports

    Note:

    Starting in Junos OS Release 17.3R2-S4, 100-Gigabit Ethernet QSFP28 ports are also supported as VCPs on QFX5200 switches.

  • On QFX5120 or EX4650 switches:

    • QFX5120-48Y or EX4650-48Y: Only the eight 40-Gigabit Ethernet QSFP+ or 100-Gigabit Ethernet QSFP28 front panel uplink ports (ports 48 through 55)

    • QFX5120-48T: Only the six 40-Gigabit Ethernet QSFP+ or 100-Gigabit Ethernet QSFP28 front panel uplink ports (ports 48 through 53)

    • QFX5120-32C: Any network ports installed with either 40-Gigabit Ethernet QSFP+ or 100-Gpbs QSFP28 transceivers

    • QFX5120-48YM: Only the eight QSFP+ front panel uplink port (ports 48 through 55)

  • On QFX5110 switches: Any 40-Gigabit Ethernet QSFP+ or 100-Gigabit Ethernet QSFP28 ports

  • Any fixed 10-Gigabit Ethernet SFP+ ports on any QFX Series switches that support these ports

EX4650 and QFX Series switches don’t have any dedicated VCPs (ports that can only be used as VCPs) or default-configured VCPs (ports that are configured as VCPs in the default factory configuration). See Virtual Chassis Port Options for details on which ports on different QFX Series switches can be VCPs.

Note:

By default, QFX5120-48YM switches come up in the default/HiGig mode and the Virtual Chassis ports come up as HiGig ports. To change this to HGoE mode, enter the request virtual-chassis mode hgoe command and reboot the switch, using the request system reboot command. To change this back to default/HiGig mode, enter the request virtual-chassis mode hgoe disable command, and reboot the switch using the request system reboot command.

You can increase VCP bandwidth between member switches by connecting multiple VCP links between the switches. When multiple VCP links interconnect the same two member switches, the links automatically form a Link Aggregation Group (LAG) bundle if they have the same speeds. For example, if you have two 40-Gigabit Ethernet QSFP+ interfaces configured as VCPs between member switches, the two links form a LAG with 80-Gbps of total bandwidth. However, 10-Gigabit Ethernet SFP+ and 40-Gigabit Ethernet QSFP+ interfaces configured as VCPs between two Virtual Chassis member switches will not become member links in the same VCP LAG.

You can set up a Virtual Chassis using either a nonprovisioned or a preprovisioned configuration. If you want to deterministically control the role and member ID assigned to each member switch, use a preprovisioned configuration. Virtual Chassis member switches can have one of three roles: primary Routing Engine, backup Routing Engine, or linecard role. In some combinations of switches in a Virtual Chassis, we recommend or require that you configure certain switches into the Routing Engine roles. See Understanding Virtual Chassis Components for more information about Virtual Chassis roles.

Adding switches to a preprovisioned configuration is simpler if you use the automatic VCP conversion feature (see Automatic Virtual Chassis Port (VCP) Conversion), which automatically converts uplink ports into VCPs on the member switches on both sides of the new VCP links as they are cabled. This method to expand a Virtual Chassis is also called autoprovisioning.

QFX5200 Switches in a Virtual Chassis

Virtual Chassis is supported on QFX5200 switches starting in Junos OS Release 17.3R2 and 17.4R1 onward.

You can interconnect up to three QFX5200 switches into a QFX5200 Virtual Chassis. QFX5200 switches cannot be combined with other types of switches in a Virtual Chassis.

The following QFX5200 switches are supported in a QFX5200 Virtual Chassis:

  • QFX5200-32C

QFX5120 or EX4650 Switches in a Virtual Chassis

QFX5120 and EX4650 switches are similar and operate the same way in a Virtual Chassis. Each QFX5120 or EX4650 switch model can only be combined with the same model of switches into a Virtual Chassis.

  • Starting in Junos OS Release 19.3R1, you can interconnect two QFX5120-48Y switches or two EX4650-48Y switches into a Virtual Chassis.

    Starting in Junos OS Release 20.2R1, you can interconnect two QFX5120-48T switches into a Virtual Chassis.

    Starting in Junos OS Release 20.3R1, you can interconnect two QFX5120-32C switches into a Virtual Chassis.

    The two member switches must be in the primary and backup Routing Engine roles.

  • Starting in Junos OS Release 20.1R1, you can interconnect up to four EX4650-48Y switches into a Virtual Chassis.

    We recommend that you configure two member switches in the primary and backup Routing Engine roles for Routing Engine redundancy, and the remaining switches in linecard role.

See Understanding Virtual Chassis Components for more information about Virtual Chassis member roles.

QFX5120 and EX4650 switches do not have dedicated or default-configured VCPs, but you can set any of the following ports as VCPs:

  • On QFX5120-48Y, QFX5120-48T, or EX4650-48Y switches: Any of the 40-Gigabit Ethernet QSFP+ or 100-Gigabit Ethernet QSFP28 uplink ports on the front panel (non-channelized). These are ports 48 through 55 on EX4650-48Y or QFX5120-48Y switches, and ports 48 through 53 on QFX5120-48T switches.

    Note:

    You can’t use any of the other ports (network ports 0 through 47) as VCPs. Running the request virtual-chassis vc-port set command on the network ports doesn’t fail, but they will not function properly as VCPs.

  • On QFX5120-32C switches: Any of the 32 network ports installed with either 40-Gigabit Ethernet QSFP+ or 100-Gigabit Ethernet QSFP28 transceivers

You configure, monitor, and maintain a QFX5120 Virtual Chassis or an EX4650 Virtual Chassis in the same way as other QFX Series Virtual Chassis. See the following for more details:

Note:

Priority flow control (PFC) is not supported on a QFX5120-48Y Virtual Chassis if the ingress and egress interfaces are located on different FPCs and the VCPs are configured in HGoE mode. You will not be able to see the PFC statistics when you run the show interfaces interface-name extensive command.

QFX5110 Switches in a Virtual Chassis

Starting in Junos OS Release 17.3R1, QFX5110 switches support Virtual Chassis.

You can interconnect up to ten QFX5110 switches or a combination of QFX5110 and QFX5100 switches into a QFX5110 Virtual Chassis. All switches can run the same software image, and you do not need to configure mixed mode.

Note: When using the QFX5110 Virtual Chassis, sometimes the master could reboot and lose connection with dual-homed video streams along with issues related to vCMTS device's connectivity for about two to three minutes. This is because, each daemon including the rpd daemon, is terminated consecutively by the system when a user does a manual reboot. When rpd daemons are shut down, TCP FIN packets are produced. When the FIN packet is created, two scenarios are possible. Either the interface is offline or it is still online. It is more normal for the interface to be active at this period. The BGP connection is subsequently cut off by sending a FIN message to the peer. This explains the reason why the BGP session was terminated.

The following QFX5110 and QFX5100 switches are supported in a QFX5110 Virtual Chassis:

  • QFX5110-32Q

  • QFX5110-48S

  • QFX5100-24Q

  • QFX5100-48S

  • QFX5100-48T

    Starting in Junos OS Release 17.3R2, you can include QFX5100-48T switches in a QFX5110 Virtual Chassis.

  • QFX5100-96S

EX4300 Switches in a QFX Series Virtual Chassis

Starting in Junos OS Release 13.2X51-D20, EX4300 switches except multigigabit models (EX4300-48MP) can be interconnected into a mixed-mode QFX Series Virtual Chassis with up to ten member switches that can be any combination of EX4300, QFX3500 switches, QFX3600 switches, and QFX5100 switches.

Related Documentation

Change History Table

Feature support is determined by the platform and release you are using. Use Feature Explorer to determine if a feature is supported on your platform.

Release
Description
20.2R1
Starting in Junos OS Release 20.2R1, you can interconnect two QFX5120-48T switches into a Virtual Chassis.
19.4R1
Starting in Junos OS Release 20.3R1, you can interconnect two QFX5120-32C switches into a Virtual Chassis.
19.3R1
Starting in Junos OS Release 19.3R1, you can interconnect two EX4650-48Y switches into a Virtual Chassis.
19.3R1
Starting in Junos OS Release 19.3R1, you can interconnect two QFX5120-48Y switches into a Virtual Chassis.
17.3R2-S4
Starting in Junos OS Release 17.3R2-S4, 100-Gigabit Ethernet QSFP28 ports are also supported as VCPs on QFX5200 switches.
17.3R2
Virtual Chassis is supported on QFX5200 switches starting in Junos OS Release 17.3R2 and 17.4R1 onward.
17.3R2
Starting in Junos OS Release 17.3R2, you can include QFX5100-48T switches in a QFX5110 Virtual Chassis.
17.3R1
Starting in Junos OS Release 17.3R1, QFX5110 switches support Virtual Chassis.
13.2X53-D25
Starting in Junos OS release 13.2X51-D25, you can configure up to ten QFX5100-96S switches into a mixed or non-mixed QFX Series Virtual Chassis.
13.2X51-D20
Starting in Junos OS Release 13.2X51-D20, QFX5100 switches support Virtual Chassis.
13.2X51-D20
In Junos OS release 13.2X51-D20, you can interconnect only up to four QFX5100-96S switches in a non-mixed QFX5100 Virtual Chassis.
13.2X51-D20
Starting in Junos OS Release 13.2X51-D20, EX4300 switches except multigigabit models (EX4300-48MP) can be interconnected into a mixed-mode QFX Series Virtual Chassis with up to ten member switches that can be any combination of EX4300, QFX3500 switches, QFX3600 switches, and QFX5100 switches.