Network Map

So here is my question. I helped to create this network for a client utilizing a trunked VLAN (QinQ) that connects into a Hybrid L2/L3 port. The client is concerned that VLANs will be bandwidth intensive because they will advertise to all devices (ports) on the receiving end of the hybrid port. Another way to put it is the client thinks that each VLAN will advertise to all VLANs on the network thereby increasing the thruput to that port and increasing the congestion unnecessarily (even if the packet is ultimately dropped).

My intention is to have each VLAN speak only to its reciprocating VLAN making it so that each connection maximizes its available bandwidth. Does this make sense and if not can you please elaborate. Thanks!

  • 4
    VLANs don't "advertise" anything. Your client (and possibly you) misunderstands what a VLAN is. The traffic on the hybrid port will be the sum of traffic on VL 1 and 2.
    – Ron Trunk
    Jul 2, 2018 at 16:45
  • The common practice would be to upsize the hybrid port so its more than the sum of provisioned bandwith. 900 Mbit inet and 100 Mbit as per your picture would be on a gigabit link minimum, but any fibreco worth their salt would install at least 10G capable lead-in and give a future option to swap to 10G optics later. Or they'd recommend a 10G access from day one. (comment cos not answering question as posted)
    – Criggie
    Jul 2, 2018 at 19:54
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.
    – Ron Maupin
    Jan 5, 2021 at 21:08

2 Answers 2


VLANs themselves don't advertise. The services running on the VLANs might. Simply extending existing production VLANs across the VPLS link might propagate "garbage" (esp. unwanted broadcasts), so best practice is to use a routed L3 (IP) link or a dedicated L2 link (with a limited number of nodes in the broadcast domain).

Each VLAN is only linked to the VLAN with the same tag on the far side, there's no inter-VLAN advertising or other traffic (unless you route it) - that's the whole point of using VLANs.


I could not quite understand what you need. Do you want, for example, that VLAN1 and VLAN2 clients do not talk to each other? There is no way to perform vlans throughput unless you perform an LACP on the final miles. What you can say is that the circuit will be transparent, and that VLAN2 clients will only talk to VLAN1 if there was L3 (Routing) equipment between these points, not that you will "broadcast" vlans to all ports. In the above configuration, traffic will be only for the configured vlans(so VLAN 1 and VLAN2) and maybe this is confusing your client.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.