I have been reading and watching some information regarding fiber networks and their deployment. One interesting point that was raised was that in a fiber network generally a DHCP server is used for the addressing but also for the bandwidth control of the end user in lieu of a traditional Radius server/PPPoE Authentication.

I have worked with Radius servers/PPPoE in conjunction with an ADSL network and this is the setup I am familiar with, however, as we move closer to fiber deployment I am considering how I would go about managing a users bandwidth/group of users bandwidth without using Radius/PPPoE.

Can someone point me in the direction of how this is currently being achieved.

For further info I am looking at using SDN switches running Cumulus Linux.

As always I apologise if I am rambling or making no sense


To clarify further I am looking at this from a service provider perspective. I am unsure as to what tools are currently being used to limit the end user to a particular speed/tariff when removing the Radius server ie the AAA/ACL. For example I want to limit customers a,b,c to xDown and xUp.

One of the video's I have seen is the following: https://www.youtube.com/watch?v=ggxI-lpk41I

Hopefully I have made the situation clearer and not worse.

  • 1
    It seems like you're talking about a service provider network (based on the comparison with DSL) as opposed to the use of fiber in an enterprise LAN or WAN, but it's not 100% clear. You might edit to clarify what kind of fiber network you're asking about. May 18, 2016 at 14:01
  • @ToddWilcox absolutely I am looking at this from a Service Provider perspective. I will modify the question to represent this. Many thanks for the response. May 18, 2016 at 15:20
  • 1
    This will depend entirely on the specific gear you use. (there are no standard dhcp options for "bandwidth".)
    – Ricky
    May 18, 2016 at 19:32

2 Answers 2


Many switches (smart ones) can do bandwidth limiting on a per-port basis - this is a robust, distributed method of limiting BW from a provider perspective for port-connected clients. Since most switches that have SFPs are also "smart switches" I'd guess it's most common.

I've never heard of it as a DHCP function (...and I have a fiber network.) For mobile clients (not fixed to a port) it's often rolled into a captive portal arrangement.

Some SDN systems (UniFi, for example) can apply a limit on a per user basis without a captive portal setup, but that's not really the DHCP server doing it (it might depend on the DHCP server telling the system that client X has connected to port Y, or to wireless SSID Q on AP Z.)


An Service Provider's last mile connection is actually 2 paths - an uplink and downlink. A property of some last mile technologies such as aDSL is a difference in bandwidth between the two, in a T1 they are the same.

The ISP is in total control of the downlink, the download speed. As for the upload bandwidth, they can control it by shaping or policing traffic passing their edge gateway.

The concept of ingress and egress QoS might point you to some good search results as well.

Your Answer

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

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