Ethernet Switching
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Ethernet Switching

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

‎06-19-2018 02:12 PM

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 REPLIES 2
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Ethernet Switching

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

‎06-19-2018 02:40 PM

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

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Ethernet Switching
Solution
Accepted by topic author cslacker
‎06-21-2018 01:10 PM

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

‎06-19-2018 09:53 PM

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-...

https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/vlan-id-e...

 

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