Switching

Expand all | Collapse all

vlan-tagging unit 0 vlan-id 0 - losing ping after sub-interface

Jump to Best Answer
  • 1.  vlan-tagging unit 0 vlan-id 0 - losing ping after sub-interface

    Posted 06-19-2018 14:12

    Model: ex4200-24p, ex4200-24t
    Junos: 15.1R6.7

     

    I have two switches back-to-back able to ping one another's directly-connected interface.  I start with this working configuration on one of the switches:

     

     ge-0/0/10 {

        unit 0 {

            family inet {

                address 10.0.0.2/24;
            }

    }

     

    Then when I add a sub-interface (unit), I can no longer ping on the 10.0.0.0/24 network. 

      

    ge-0/0/10 {
      vlan-tagging;
        unit 0 {
           vlan-id 0;
              family inet {
                  address 10.0.0.2/24;
              }
          }
          unit 15 {
              vlan-id 15;
              family inet {
                  address 10.0.15.2/24;
              }
          }
      }

     

    show interfaces terse reveals that the interfaces are all up/up.  I am losing an ospf neighborship, too.

     

    Any insights?  Is this expected behavior?



  • 2.  RE: vlan-tagging unit 0 vlan-id 0 - losing ping after sub-interface

    Posted 06-19-2018 14:41

    Yes, this is expected behavior - vlan 0 is reserved by Juniper and cannot be used.  I believe the EX4200 should support vlans 1-4094.



  • 3.  RE: vlan-tagging unit 0 vlan-id 0 - losing ping after sub-interface
    Best Answer

     
    Posted 06-19-2018 21:54

    Hi cslacker,

     

    Juniper reserves vlan-id 0 and 4095 for internal use. These vlans are not available for use  by customers. Other vlan 1 to 4094 can be used by customers.

    A physical interface can have 4094 sub-interfaces for 4094 (1-4094) vlans. 

     

     

    A subinterface always expects a vlan tag and due to which you are losing connectivity/ospf neighborship on your 10.0.0.0/24 network.

     

    Please refer to the following links.

    https://www.juniper.net/documentation/en_US/junos/topics/concept/interfaces-layer3-subinterfaces-ex-series.html

    https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/vlan-id-edit-interfaces-interfaces-ex-series.html