[j-nsp] Juniper M7i & Cisco 3650 vlan configuration difficulties

[Chris Davies]

I've got a Juniper M7i and a Cisco 3650.  I need to run vlan-tagging on
the interface that connects the two due to another piece of hardware 
which requires it.

Juniper:

     ge-1/3/0 {
         description "Aggregate LAN";
         vlan-tagging;
         link-mode full-duplex;
         unit 0 {
             vlan-id 2;
             family inet {
                 address xx.xx.195.249/30;
             }
         }
     }

Cisco:

interface GigabitEthernet0/1
  no switchport
  ip address x.x.195.250 255.255.255.252

As soon as I add the vlan-tagging to the gigE port on the Juniper, the
two units cannot communicate.

I also tried to configure the GigE port on the cisco as

interface vlan 2
   ip address x.x.195.250 255.255.255.252
interface GigabitEthernet0/1
   switchport access vlan 2

However, that also does not work.  Cisco's vlan is an internal 
designation, not 802.1q.

If I try to turn on 802.1q encapsulation:

#switchport trunk encapsulation dot1q
Command rejected: Gi0/1 not a switching port.

#switchport encapsulation dot1q
Command rejected: Gi0/1 not a switching port.

Is there a way to configure a port so that the primary interface doesn't 
require vlan tagging, but a secondary interface does?  Or, is there a 
way to assign two other IPs as VLANS that are not attached to an 
interface but are able to be reached through a direct IP address?

Thank you.