I have some ingress untagged voice traffic coming through the MPLS network and obviously I have some concerns about this traffic being de-prioritised should there is congestion on the MPLS backhaul. In order to mitigate this, I was wondering whether it would be possible to route this traffic through a dedicated VRF across the MPLS network and to allocate some bandwith onto this VRF that would guarantee good voice quality as long as I don't exceed this pre-allocated BW. Does this concept of VRF BW allocation exist? Or are VRFs purely for routing purposes and have nothing to do with BW?

Regards, Pablo

  • 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 can provide and accept your own answer.
    – Ron Maupin
    Commented Dec 25, 2018 at 8:39

1 Answer 1


I believe you mean VPN, not VRF. A VRF is a routing instance local to the router.

Creating a separate VPN will likely do nothing to help your voice traffic. If the backbone is congested, then everything will suffer.

It's not clear from your question whether the MPLS network is yours or is a carrier's network. But it is possible to prioritize traffic in the MPLS network. Check with your carrier or your backbone team for the best solution. It may be possible to mark the voice traffic so that it can be prioritized in the backbone.

  • Thanks Ron. I take then that the creation of a new VRF/VPN wouldn't offer BW preservation as I was thinking... The option of prioritising traffic on the MPLS backbone (via QoS marking) is not possible (that's why I mentioned untagged traffic) and that's why I was exploring this. Commented Jun 12, 2018 at 12:31
  • based on the info you've provided, it's impossible to say. IF the carrier allocates bandwidth per VPN, and IF the network is not oversubscribed, then it is possible. Otherwise, no.
    – Ron Trunk
    Commented Jun 12, 2018 at 12:48

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