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Configuring an EX2300, EX3400, EX4300, or EX4400 Virtual Chassis

You can use the procedures in this topic to configure:

  • A non-mixed Virtual Chassis composed of EX2300, EX3400, EX4300, or EX4400 switches

  • A mixed EX4300 Virtual Chassis with EX4300 multigigabit model (EX4300-48MP) switches interconnected with other EX4300 model switches

You can mix non-multigigabit model EX4300 switches with other switches in a Virtual Chassis or Virtual Chassis Fabric (VCF) in the following supported combinations. In these cases, use the following configuration procedures instead of the procedures in this topic:

Use the following requirements and guidelines to plan the devices to include in your Virtual Chassis:

  • EX2300 switches:

    In Junos OS releases prior to 18.4R1, you can interconnect EX2300 and EX2300-C switches into a Virtual Chassis, or you can interconnect EX2300 multigigabit model switches (EX2300-24MP and EX2300-48MP) into a Virtual Chassis. You can’t combine EX2300 or EX2300-C switches with EX2300 multigigabit model switches in a Virtual Chassis.

    Starting in Junos OS Release 18.4R1, you can combine EX2300, EX2300-C, and EX2300 multigigabit switches in the same non-mixed Virtual Chassis, and use any of these switches in any role (primary Routing Engine role, backup Routing Engine role, or linecard role).

  • EX3400 switches:

    You can interconnect EX3400 switches only with other EX3400 switches in a Virtual Chassis (no mixed mode).

  • EX4300 switches:

    You can interconnect EX4300 switches excluding multigigabit models into a non-mixed EX4300 Virtual Chassis.

    You can also connect EX4300 multigigabit model switches (EX4300-48MP) together into a non-mixed EX4300 Virtual Chassis.

    You can combine EX4300 multigigabit model switches with other EX4300 model switches as a mixed EX4300 Virtual Chassis with the following configuration:

    • You must configure the Virtual Chassis into mixed mode.

    • You must also include a special port mode option (ieee-clause-82) when you configure mixed mode on the EX4300 switches that are not multigigabit models. This port mode enables the Virtual Chassis ports (VCPs) on EX4300 non-multigigabit model switches to communicate with VCPs on multigigabit model members.

      Note:

      If you remove a non-multigigabit model EX4300 switch from a mixed EX4300 Virtual Chassis with multigigabit model members, remember to disable ieee-clause-82 port mode on the removed switch if you want to reconfigure it as a standalone switch or use it in any other type of mixed Virtual Chassis or non-mixed Virtual Chassis. Otherwise, the VCPs will not connect with other members in the new Virtual Chassis. (See Removing or Replacing a Member Switch of a Virtual Chassis Configuration.)

    • The members in the Routing Engine role must be multigigabit model (EX4300-48MP) switches.

  • EX4400 switches:

    You can interconnect EX4400 switches only with other EX4400 switches in a Virtual Chassis (no mixed mode support).

Use these guidelines to plan the VCP connections:

  • In a non-mixed EX4300 Virtual Chassis with only EX4300 multigigabit model (EX4300-48MP) switches, interconnect the member switches using the dedicated VCPs—the 40-Gpbs QSFP+ ports on the rear panel. These are the only ports that can be used as VCPs on EX4300-48MP switches.

  • In a mixed EX4300 Virtual Chassis with a combination of EX4300 multigigabit model switches and other EX4300 model switches, you must use 40-Gbps QSFP+ ports on the other EX4300 model switches as VCPs and interconnect those ports with the dedicated VCPs on the multigigabit model switch members.

    Note:

    All QSFP+ ports on EX4300 non-multigigabit switches are configured as VCPs in the default factory configuration.

  • In non-mixed EX2300, EX3400, and non-multigigabit model EX4300 Virtual Chassis, use uplink ports that you configure as VCPs or that are VCPs by default to interconnect the member switches. Keep the following in mind about VCPs on these switches:

    • EX2300 switches do not have any ports that are configured by default as VCPs. You must explicitly configure the ports you want to use as VCPs.

    • The QSFP+ uplink ports on EX3400 and EX4300 switches support 40-Gbps speeds and can connect switches that are up to 492 feet (150 m) apart. These are set as VCPs by default, so you don’t need to explicitly configure them.

    • You can configure the SFP+ uplink ports on any of these switches as VCPs. These ports support 10-Gbps speeds and can connect switches that are up to 6.2 miles (10 km) apart.

      Note:

      The only exceptions are the four built-in 10-Gbps SFP+ ports on 32-port EX4300 switches. You can’t use the built-in ports as VCPs.

    • You can’t use uplink ports installed with SFP transceivers as VCPs on any of these switches.

  • The simplest way to interconnect EX3400 or EX4300 switches into a non-mixed EX3400 or EX4300 Virtual Chassis is to install the switches within 492 feet of one another and interconnect them into a Virtual Chassis by using the QSFP+ ports.

    For an EX3400 or EX4300 Virtual Chassis, if you must install member switches in locations that are more than 492 feet apart (such as at a different site or at a distant location within the same site), or if you are using the QSFP+ ports for another purpose, or for any EX2300 Virtual Chassis, you must configure SFP+ uplink module ports into VCPs.

  • In an EX4400 Virtual Chassis, you must use the default VCPs to interconnect the member switches, which are the only ports that can be used as VCPs on these switches. The default VCPs are the two 100-Gbps ports on the rear panel, which operate as two logical 50-Gbps VCPs each for a total of four logical VCP interfaces on the switch. If you previously converted the default VCPs into network ports, you must convert them back into VCPs using the request virtual-chassis mode network-port disable command. You must then reboot the switch for the port mode conversion to take effect.

  • If you need additional VCP bandwidth between two member switches, you can configure additional ports as VCPs and create redundant links between the member switches.

    Redundant VCP links are not required to be the same speed, but the links with identical speeds automatically form a VCP link aggregation group (LAG) to provide resiliency to the Virtual Chassis. For example, if you have two 40-Gbps QSFP+ ports and two 10-Gbps SFP+ ports configured as VCPs connecting the same two member switches to each other, the member switches form two LAGs—one LAG with two 40-Gbps QSFP+ port links and another with two 10-Gbps SFP+ port links.

Note:

A Virtual Chassis configuration has two Routing Engines—the primary switch and the backup switch. We recommend that you always use commit synchronize rather than simply commit to save configuration changes made for a Virtual Chassis. This ensures that you save the configuration changes on both Routing Engines at the same time.

You can configure the Virtual Chassis using either of the following options:

  • A nonprovisioned configuration—The primary sequentially assigns a member ID to other member switches. The role is determined by the primary-role priority value and other factors in the primary-role election algorithm.

  • A preprovisioned configuration—You can deterministically control the member ID and role assigned to a member switch by tying the member switch to its serial number.

All member switches must be running the same version of Junos OS to form a Virtual Chassis.

Note:

You must configure a VLAN on all interfaces in the Virtual Chassis, except on member switch 0, before the interfaces can send or receive traffic. This is because the interfaces on member switch 0 are initially placed into the default VLAN, but the interfaces on all other member switches are not placed into any VLAN. See Configuring VLANs for EX Series Switches with ELS Support (CLI Procedure).

Note:

On an EX4300 Virtual Chassis, STP is disabled on all interfaces except the interfaces on member switch 0 until some type of spanning-tree protocol is enabled. See Configuring RSTP on EX Series Switches (CLI Procedure) (RSTP is the default spanning-tree protocol), Configuring MSTP on Switches, or Configuring VSTP Protocol to enable a spanning-tree protocol on the interfaces in your EX4300 Virtual Chassis.

Configuring an EX2300, EX3400, EX4300, or EX4400 Virtual Chassis with a Nonprovisioned Configuration File

You can use a nonprovisioned configuration to configure an EX2300, EX3400, EX4300, or EX4400 Virtual Chassis.

This procedure shows example configuration steps for a Virtual Chassis with two to ten members. You can have up to 4 members in an EX2300 Virtual Chassis, and up to 10 members in an EX3400, EX4300, or EX4400 Virtual Chassis.

Note:

We recommend that you physically cable the interconnecting ports as the final step of this procedure.

You can, however, configure the Virtual Chassis while the cables are physically connected.

  1. Power on only the switch that you will use as the primary switch.
    Note:

    For a mixed EX4300 Virtual Chassis with EX4300 multigigabit model (EX4300-48MP) switches and other EX4300 model switches, the members in the primary and backup Routing Engine roles must be EX4300 multigigabit model switches.

  2. (Required for a mixed EX4300 Virtual Chassis only) Set the primary switch into mixed mode, and reboot the switch for the change to take effect:
  3. If you are configuring a mixed Virtual Chassis, wait for the reboot to complete before performing this step. Run the EZSetup program on the primary switch, specifying the identification parameters. See Connecting and Configuring an EX Series Switch (CLI Procedure) for details.
    Note:

    The properties that you specify for the primary switch apply to the entire Virtual Chassis configuration.

  4. (Optional) Configure the primary switch with the virtual management Ethernet (VME) interface for out-of-band management of the Virtual Chassis (see Understanding Global Management of a Virtual Chassis):
  5. (Optional) Configure primary-role priority for the other member switches. For example, for a ten-member Virtual Chassis:

    The primary-role priority value determines the roles in a non-provisioned Virtual Chassis configuration. The switches with the highest primary-role priority values assume the primary and backup roles. All other switches assume the linecard role.

    If you do not configure the primary-role priority for any switch in your Virtual Chassis, including when you do not configure the Virtual Chassis, all switches assume the default primary-role priority of 128. The primary-role election algorithm selects the roles for the member switches. In most cases, the switches that have been powered on the longest assume the primary and backup roles when all Virtual Chassis member switches are configured with the same primary-role priority. See Understanding How the Primary in a Virtual Chassis Is Elected for additional information on the primary-role election algorithm.

    A switch with a primary-role priority of 0 never assumes the primary or backup role.

    Note:

    We recommend that you specify the same primary-role priority value for the intended primary and backup members.

  6. (Optional: Recommended for a two-member Virtual Chassis) On the primary switch, disable the split and merge feature:
  7. Commit the configured items.
  8. Power on the other member switches.
  9. (Required for a mixed EX4300 Virtual Chassis only) Set each additional individual EX4300 multigigabit model (EX4300-48MP) switch into mixed mode and reboot the switch for the change to take effect:

    Set each of the other EX4300 switches that are not multigigabit model switches into mixed mode with the ieee-clause-82 option, and reboot the reboot the switch for the change to take effect:

  10. If needed, on each individual member switch, configure SFP+ uplink ports that will be used as VCPs to interconnect the member switches.

    This step is not needed for:

    • EX4300 multigigabit model (EX4300-48MP) switches, which have dedicated VCPs on the rear panel of the switch. Dedicated VCPs do not require configuration, and you must use the dedicated ports on these switches because no other ports on these switches are supported as VCPs.

    • EX3400 switches and EX4300 member switches that are not multigigabit model switches, if you are using the QSFP+ ports that are VCPs by default. You only need to configure a QSFP+ port as a VCP if you previously configured the QSFP+ port into a network port. In that case, you can perform this step to configure the QSFP+ port back into a VCP.

    • EX4400 switches, which have the rear panel 100 Gigabit Ethernet QSFP28 ports set as VCPs by default. Those are the only ports that can be used as VCPs on these switches. If you previously converted the default VCPs into network ports, you can't convert them back into VCPs using the command in this step. See Step 11 instead.

    Use the request virtual-chassis vc-port command to configure SFP+ or QSFP+ ports into VCPs. For example, for a four-member Virtual Chassis:

  11. (EX4400 switches only) If the ports that you will use as VCPs were previously converted into network ports on any member switches, convert them back into VCPs in this step using the request virtual-chassis mode network-port disable command, and reboot the affected switches for the change to take effect. The request virtual-chassis vc-port command shown in Step 10 doesn't convert a network port into a VCP on EX4400 switches.

    EX4400 switches have the two rear panel 100 Gigabit Ethernet QSFP28 ports configured into four logical 50-Gbps VCPs by default. These are the only ports that you can use to connect member switches into an EX4400 Virtual Chassis. If you previously converted them to network port mode, you must disable network port mode to restore them to the default VCP mode for the Virtual Chassis to form when you cable the member switches together. You can use the show virtual-chassis mode command to check whether the switch has network port mode enabled or not.

    Note:

    This command changes the port mode for all of the VCPs on the switch. The two ports must both operate together as VCPs or as network ports. You are also required to reboot the switch for any mode command changes to take affect. You can optionally include the reboot option with the mode command to reboot the switch immediately, as shown here. Otherwise, you can alternatively reboot the switch later with a separate reboot command.

    For example:

  12. Cable the ports interconnecting the members if they were not connected earlier.
Note:

If you want to change the member ID that the primary has assigned to a member switch, use the request virtual-chassis renumber command.

Configuring an EX2300, EX3400, EX4300, or EX4400 Virtual Chassis with a Preprovisioned Configuration File

Preprovisioning a Virtual Chassis configuration allows you to assign the member ID and role for each switch in the Virtual Chassis.

This procedure shows example configuration steps applicable to a Virtual Chassis with two to ten members; up to 4 members are supported in an EX2300 Virtual Chassis, and up to 10 members are supported in an EX3400 and EX4300 Virtual Chassis.

To configure a Virtual Chassis using a preprovisioned configuration:

Note:

We recommend that you physically cable the optical ports as the final step of this procedure.

You can, however, configure the Virtual Chassis while the cables are physically connected.

  1. Make a list of the serial numbers of all the switches to be connected in a Virtual Chassis configuration.
    Note:

    Serial number values are case-sensitive.

  2. Note the intended role (routing-engine or line-card) of each switch. If you configure the member with a routing-engine role, it is eligible to function in the primary or backup role. If you configure the member with a line-card role, it is not eligible to function in the primary or backup role.
    Note:

    For a mixed EX4300 Virtual Chassis with EX4300 multigigabit model (EX4300-48MP) switches and other EX4300 model switches, the members in the primary and backup Routing Engine roles must be EX4300 multigigabit model switches.

  3. Power on only the switch that you plan to use as the primary switch.
  4. (Required for a mixed EX4300 Virtual Chassis only) Set the primary switch into mixed mode, and reboot the switch for the change to take effect:
  5. If you are configuring a mixed Virtual Chassis, wait for the reboot to complete before performing this step. Run the EZSetup program on the primary switch, specifying the identification parameters. See Connecting and Configuring an EX Series Switch (CLI Procedure) for details.
    Note:

    The properties that you specify for the primary switch apply to the entire Virtual Chassis configuration.

  6. (Optional) Configure the primary switch with the virtual management Ethernet (VME) interface for out-of-band management of the Virtual Chassis (see Understanding Global Management of a Virtual Chassis):
  7. Specify the preprovisioned configuration mode:
  8. Specify all the members that you want included in the Virtual Chassis, listing each switch’s serial number with the desired member ID and role. For example, for a ten-member Virtual Chassis:
    Note:

    You can retrieve the switch’s serial number using the show chassis hardware command output or by viewing the serial number ID label on the switch. See Locating the Serial Number on an EX2300 Switch or Component, Locating the Serial Number on an EX3400 Switch or Component, or Locating the Serial Number on an EX4300 Switch or Component. Serial number values are case-sensitive.

  9. (Optional: Recommended for a two-member Virtual Chassis) Disable the split and merge feature:
  10. Commit the configured items.
  11. Power on the other member switches. The member IDs and roles have been determined by the configuration, so you can power on the member switches in any order.
  12. (Required for a mixed EX4300 Virtual Chassis only) Set each additional individual EX4300 multigigabit model (EX4300-48MP) switch into mixed mode and reboot the switch for the change to take effect:

    Set each of the other EX4300 switches that are not multigigabit model switches into mixed mode with the ieee-clause-82 option, and reboot the reboot the switch for the change to take effect:

  13. If needed, on each individual member switch, configure the SFP+ uplink ports that will be used as VCPs to interconnect the member switches.

    This step is not needed for:

    • EX4300 multigigabit model (EX4300-48MP) switches, which have dedicated VCPs on the rear panel of the switch. Dedicated VCPs do not require configuration, and you must use the dedicated ports on these switches because no other ports on these switches are supported as VCPs.

    • EX3400 switches and EX4300 member switches that are not multigigabit model switches, if you are using the QSFP+ ports that are VCPs by default. You only need to configure a QSFP+ port as a VCP if you previously configured the QSFP+ port into a network port. In that case, you can perform this step to configure the QSFP+ port back into a VCP.

    • EX4400 switches, which have the rear panel 100 Gigabit Ethernet QSFP28 ports set as VCPs by default. Those are the only ports that you can use as VCPs on these switches. If you previously converted the default VCPs into network ports, you can't convert them back into VCPs using the command in this step. See Step 14 instead.

    Use the request virtual-chassis vc-port command to configure SFP+ or QSFP+ ports into VCPs. For example, for a four-member Virtual Chassis:

  14. (EX4400 switches only) If the ports that you will use as VCPs were previously converted into network ports on any member switches, convert them back into VCPs in this step using the request virtual-chassis mode network-port disable command, and reboot the affected switches for the change to take effect. The request virtual-chassis vc-port command shown in Step 13 doesn't convert a network port into a VCP on EX4400 switches.

    EX4400 switches have the two rear panel 100 Gigabit Ethernet QSFP28 ports configured into four logical 50-Gbps VCP interfaces by default. These are the only ports that you can use to connect member switches into an EX4400 Virtual Chassis. If you previously converted them to network port mode, you must disable network port mode to restore them to the default VCP mode for the Virtual Chassis to form when you cable the member switches together. You can use the show virtual-chassis mode command to check whether the switch has network port mode enabled or not.

    Note:

    This command changes the port mode for all of the VCPs on the switch. The two ports must both be set together to VCP port mode or to network port mode. You are also required to reboot the switch for any mode command changes to take affect. You can optionally include the reboot option with the mode command to reboot the switch immediately, as shown here. (Otherwise, you can alternatively reboot the switch later with a separate reboot command.)

    For example:

  15. Cable the ports interconnecting the members if they were not connected earlier.
Note:

You cannot modify the primary-role priority when you are using a preprovisioned configuration. The primary-role priority values are generated automatically and controlled by the role that is assigned to the member switch in the configuration file. The two Routing Engines are assigned the same primary-role priority value. However, the member that was powered on first has higher prioritization according to the primary-role election algorithm. See Understanding How the Primary in a Virtual Chassis Is Elected.