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[EX] How to troubleshoot the Virtual Chassis (VC) management Ethernet interface (VME)

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Article ID: KB25724 KB Last Updated: 25 Feb 2020Version: 3.0
Summary:

This article provides information on troubleshooting the Virtual Chassis (VC) management Ethernet interface (VME).

 

Symptoms:
  • The management ethernet interface allows users to access the VC via any management Ethernet port of member switches.

  • With this feature, users can not only use the master switch management Ethernet port to connect to the VC, but also use the backup or linecard switches management Ethernet port to manage the VC.

 

Solution:

The Virtual Management Ethernet (VME) interface provides one global interface to access the VC. Regular Junos OS commands can be used to configure the VME interface, just like any other L3 interface or management interface, such as me0.

For example:

set interfaces vme unit 0 family inet address <ip address>

The VME interface uses the master member switch's me0 interface to provide management access. If the master's me0 interface goes down, it will use the backup's me0 interface to provide management connectivity. If the backup's me0 interface goes down, it will pick up a linecard's me0 (which has the lowest member ID).

Note: A default 'me0.0' interface is created by the system on both the master and backup. On linecards, 'bme0.<x>' is created, in which 'x' is '32769 + member number'.

To access individual switches via their management interface (if required), their respective me0 interface can be directly configured with an IP address.

For example:

groups {

    member0 {
        interfaces me0 unit 0 family inet address <address0>
    }
member1 {
    interfaces me0 unit 0 family inet address <address1>
}
}

The above configuration is applicable only on the master and backup, on which me0.0 interfaces are present.

To directly use the linecard's me0 interface, perform the following procedure:

  1. The following special configuration is required to take it away from the management VLAN:

    virtual-chassis {
        member 2 {
            no-management-vlan;
        }
    member 3 {
        no-management-vlan;
    }
    }
  2. Now, me0.<xxxxx> should be configured from the shell as follows:

    root# ifconfig me0.0 local=10.10.10.1 netmask=255.255.255.0

Output of show interface on master:

bme0.32770 and bme0.32771 are created by the management VLAN to manage the VC via the backup and linecard. Currently, these interfaces are set to down, as the master's me0 is up. If the master's me0 goes down, the backup's bme interface (bme0.32770) is enabled.

Output of show interface from the backup:

bme0.32770 is down, as the master’s me0 interface is currently up.

Output of show interface from the first linecard:

bme0.37771 is down, as the master’s me0 interface is currently up.

Troubleshooting the virtual chassis management Ethernet interface:

  1. Run the show interfaces *me* terse command on all devices (as shown above) to make sure that all relevant me / bme interface states are set up properly.

  2. Run the following command and make sure that the routes are set up properly:

  3. The VME and current me0 MAC address should match:

Collecting debugging data for further troubleshooting:

  • show interfaces me0 extensive

  • show interfaces vme extensive

  • show interfaces *me* terse

  • show route forwarding-table family ethernet-switching | find private

  • show route forwarding-table family vlan-classification | find private

  • tcpdump -i <me0 or vme> arp > /var/tmp/tcpdump_member<id>_me0.txt (run it for a minute. Upload this log file for JTAC)

  • show virtual-chassis status

  • show ethernet-switching table management-vlan

  • show system statistics bridge (collect the output twice with an interval of 5 seconds)

If me0 on master is not up, then go to the backup or a linecard, on which me0 is up and part of the management VLAN, by looking at bme0.xxxxx; which is up.

Note: 'bme0.32768' is not part of the management VLAN; so ignore this IFL.

Troubleshooting example:

bme0.32770 is up, which means that the me0 interface of the member1 backup is currently up and me0 on the master switch is down. Go to the member, on which me0 is up and part of the management VLAN. In this example, it is member 1.

 

Modification History:

2020-02-25: Article checked for accuracy and found to be valid and relevant; no changes made

 

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