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QoS and Bandwidth Throttling

Userlevel 4
Create Date: Mar 21 2012 7:00AM

Typically, the ports are only able to be given one QoS profile or a Vlan is assigned only one QoS profile. In this setup, we were looking to limit the bandwidth (which can be done on the port level, but not so much the Vlan level) and assign two QoS profiles to one port. If we assigned the QoS profiles based on the Vlan, this would handle giving the vital Vlan higher priority over the littlest Vlan, but the only way we would be able to limit the bandwidth would be thru limiting the bandwidth on the port level. The issue I had was that the ports, as mentioned before, can only have one QoS profile assigned to them which would limit the bandwidth according to only one of the QoS profiles. Is there any way around this? So that the bandwidth can be limited on the uplinked ports to the AP, containing different Vlans? For example, when one Vlan's traffic comes thru, it gets most of the bandwidth, and when the other Vlan comes thru, it gets less bandwidth allocation. The tricky part is that both Vlans are on the same port, tagged with one Vlan and untagged in the other.

Thanks, Here is the current QoS configuration on the switch: vital vlan, important vlan, necessary vlan (most bandwidth, higher priority)

littlest vlan (least bandwidth, lower priority)

create qosprofile qp3

conf vlan vital qosprofile qp3

conf vlan important qosprofile qp3

conf vlan necessary qosprofile qp3

conf vlan littlest qosprofile qp1

conf dot1p type 2 qp3

conf qosprofile egress qp1 minbw 0 maxbw 20 ports 10,14,15

conf qosprofile egress qp3 minbw 0 maxbw 80 ports 10,14,15

(from Joshua_Winchell)

1 reply

Userlevel 4
Create Date: Mar 21 2012 5:09PM

Imp thing to understand here is that by setting the maxBW you arae restrciting the BW to not go more than 80 or 20%. In this case you are not using you BW correctly I believe.

What you can do is. Create a single Qos profile for non-vital traffic and set the max BW to 20 for it so that under any circumstance that VLAN won't use more than20% of the BW and then apply the QP to that VLAN and let other VLAN be in the default setting which would allow it to occupy 100% of BW if required.

So basically the vital VLAN gets 0-100% of BW

and non-vital gets 20% (max)

Let me know what works out for you.

(from Arpit_Bhatt)