Limiting bandwidth per VLAN

--chris----chris-- Member Posts: 1,518 ■■■■■□□□□□
I seem to be getting more and more network questions at work, but being that we support small business's non of my coworkers have a great deal of experience on the networking side of things once we get beyond sonicwall/SMB size firewall configs and setting up basic ingress networking via bridged ISP equipment.

So here is the question I was presented with today:

Customer A has a L3 switch with three VLANs on it. One for voice that goes straight to the router which then sends it out its own internet connection, one for data/production and one that is not in use yet.

The third one that is "not in use" yet is one that was set aside to be used in a guest wifi implementation that we are working on. They want to limit this third VLANs available bandwidth (both up/down). From this link:

https://supportforums.cisco.com/discussion/11804466/bandwidth-limit-vlans-using-cisco-3750-layer-3-switch

It looks like that type of work should really be done by a router, not a L3 switch right?

If I were to put this on a router, the config would be similar to this (I beleive):
https://supportforums.cisco.com/discussion/10956426/limiting-bandwidth-cisco-router-possible-1800-series

Let me run through this config out loud, someone let me know if I am way off base:

The access lists that are created apply the "policy-map" & "class-map" statements to limit the bandwidth right? But since these are "fair use" policy's that would mean the third "unused" VLAN could potentially use all of the bandwidth available. What would be a good way to work around this?

Comments

  • Dieg0MDieg0M Member Posts: 861
    You can read a QoS book to get more information but here's a quick breakdown. In the class-map you will match your traffic type, either per ACL, dscp, NBAR, etc. In the policy-map you will define what you want to do with your traffic defined in your class-map. Class-default is for all other traffic.
    Follow my CCDE journey at www.routingnull0.com
  • --chris----chris-- Member Posts: 1,518 ■■■■■□□□□□
    Great, thanks for referencing the QoS books...I did not even think books on the subject existed.

    I found a way to make this happen in the Sophos appliance they are using, via the GUI. Not as exciting as sourcing a solution from Cisco's documentation then playing with its switches on the CLI but it got the job done.
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