One way you could do this:
Given the following two interfaces:
interfaces {
ge-1/0/1 {
flexible-vlan-tagging;
encapsulation flexible-ethernet-services;
unit 1 {
encapsulation vlan-bridge;
vlan-tags outer 1 inner 600;
}
}
ge-1/0/2 {
flexible-vlan-tagging;
encapsulation flexible-ethernet-services;
unit 1 {
encapsulation vlan-bridge;
vlan-tags outer 336 inner 600;
}
}
Then normalise at your bridge-domain by specifying vlan-id "none":
bridge-domains {
QT {
vlan-id none;
interface ge-1/0/1.1;
interface ge-1/0/2.1;
}
}
You'll then see when you look at your interfaces that the MX will pop both tags on ingress, and then push two new ones to match the egress interface eg:
Logical interface ge-1/0/1.1 (Index 345) (SNMP ifIndex 538)
Flags: Device-Down SNMP-Traps 0x0
VLAN-Tag [ 0x8100.1 0x8100.600 ] In(pop-pop) Out(push-push 0x8100.1 0x8100.600) <--
Encapsulation: VLAN-Bridge
Input packets : 0
Output packets: 0
Protocol bridge, MTU: 1522
Flags: Is-Primary
Logical interface ge-1/0/2.1 (Index 346) (SNMP ifIndex 542)
Flags: Device-Down SNMP-Traps 0x0
VLAN-Tag [ 0x8100.336 0x8100.600 ] In(pop-pop) Out(push-push 0x8100.336 0x8100.600) <--
Encapsulation: VLAN-Bridge
Input packets : 0
Output packets: 0
Protocol bridge, MTU: 1522