Vlan interface limitations on J-series with ES

  • administrators

    When attempting to configure a DHCP client on a vlan interface like this:

    set interfaces vlan.100 family inet dhcp

    A commit spawns an error that says I can only set up the DHCP client on a physical ethernet interface.  Why does this even matter?  A VLAN interface with family inet configured gets its own MAC address.  Shouldn’t be a problem.

    Also, it appears that if I set up a trunk between a J-series ES router and an EX switch, that any vlan.X interfaces with L3 addresses on the J-series are not available over the trunk from hosts on the switch.  The only way to make it work is to assign the L3 address to a tagged logical unit on the physical interface. This is annoying.  Can anyone else confirm this behavior?

    I also read that link aggregation is not supported on the built in ports on the J-series.  But it lets me configure it, and the link appears to be up.  What is the real story on this?  None of the Juniper engineers I spoke with knew much about it and were surprised that it even let me configure it.  I have not tried sending traffic over it yet, but the ae0 interface is up/up on both ends.

  • administrators

    9.4 lets me set the DHCP client on an L3 vlan interface now.  Haven’t really tested the other two items.