Question on hierarchical QinQ / tag stacking (CRS326)

RouterOS General
1

Hi experts,

following scenario:

  • Switch CRS326
  • Source Systems (SS) on different ethernet ports, every system uses its own VLANs (VLAN_SSx)
  • Target System (TS) connected to ETH1 as trunk.

Goals:

  • Separation of Traffic of different Source Systems
  • All the traffic switch ←→ TS shall be communicated under one dedicated VLAN_T

Idea:

  • Let the switch add 2 layers of VLAN TAGs to achieve the goals:
    • Use “tag stacking” on physical ports and encapsulate SS traffic in dedicated Source System VLANs (1 per SS) (first added layer of added VLAN TAG –> intermediate leyer VLAN IDs 1…x
    • Then add another layer of VLAN with VLAN ID VLAN_T to packets and send all packets with same “outer” VLAN ID on ETH1.

As i could not find instructions and was not able to establish a solution inside the switch. Therefor we configured 2 separate bridges in the switch which are connected by using two physical ports and a external patch cable to connect them.

Is there a solution which avoids using the “external connection” and achieve the Q-in-Q-in-Q solution in one switch?

thanks and best regards,

Roman

2

Do you really need Q-in-Q(-in-Q) solution? If TS is set up as trunk peer of your switch, then it will have two VLAN interfaces with distinct IP addresses ... it'll be able to communicate with each of SSes (which will be untagged members of different VLANs) ... and those SSes won't be able to communicate with each other (unless there's a router which will pass packets between both VLANs ... TS can potentially be such router but I'm pretty sure that all OSes capable of using tagged VLANs can be configured not to route traffic between different interfaces).

3

Thanks for input.

The thing is that there are

  • multiple switches in between the CRS and TS which also need to be configured for every VLAN to be sent through
  • multiple different SS (>15), not only 2 - whose VLANs also would have to be configured on every switch in between…

Or didn’t i get your point properly? :thinking: