bandwidth limiting

[paulkilcoyne]

Hi Guys,

hope this finds you all well.

I have a 3845 Router with three connected interfaces, one to my WAN, one to my LAN and another to my wifi zone. I want to limit the amount of WAN bandwidth the WIFI zone can take to say a max of one third and not restrict WAN bandwidth from the LAN at all.

Is this possible?

Thanks,

Paul

[Dan-Ciprian Cicioiu]

Hi Paul ,

You can use CAR on the interface to Wifi zone.

Interface x/y

rate-limit input ...

rate-limit output ...

or CB policing

policy-map WIFI-IN

class class-default

   police cir 20000

policy-map WIFI-OUT

class class-default

   police cir 20000

int x/x

service-policy WIFI-IN in

service-policy WIFI-OUT out

Dan

[paulkilcoyne]

Hi Dan,

thanks for the reply. I'd like to keep this as simple as possible so here goes;

So assuming my wan bandwidth is 50meg and I want to limit wifi to 1/4 (12.5meg) of this then on my wifi interface I do the following:

int gi 0/0

rate-limit input 12500000 ( bits per sec )

rate-limit output 12500000

So now wifi connected via gi 0/0 can only download a max of 12.5meg/sec and the same for uploading.

Is this correct?

Thanks again,

Paul

[Dan-Ciprian Cicioiu]

Hi Paul ,

I suppose that you have also some traffic from WIFI to LAN is that correct.

Because with this configuration you will limit all the traffic from WIFI

Dan

[paulkilcoyne]

Hi Dan,

I see your point. Is there a better solution?

Thanks,

Paul

[Dan-Ciprian Cicioiu]

Yes , using CAR with access-list , and dening the traffic from WIFI to LAN.

rate-limit input access-group 100

rate-limit output access-group 101

ip access-list extended 100

deny ip wifi-net lan-net

permit ip any any

ip access-list extended 101

deny ip lan-net wifi-net

permit ip any any

Dan

[paulkilcoyne]

Hi Dan,

so it doesn't matter about wifi to lan traffic. Here is the config I'm using:

rate-limit output 3000000 562500 1125000 conform-action transmit exceed-action drop

rate-limit input 3000000 562500 1125000 conform-action transmit exceed-action drop

How does it look to you?

I don't really understand the "Normal burst bytes" and "Maximum burst bytes" terms but I followed a post and calculated these as follows:

Normal burst bytes = configured rate/8 * 1.5 seconds

Maximum burst bytes = configured rate * 2

Am I limiting the bandwidth up and down to 3meg?

Thanks,

Paul

[Dan-Ciprian Cicioiu]

Hi Paul,

Yes. You are using the recommanded values. Normal burst amoung of traffic in bytes send on each time interval ( 1.5 seconds ). Maximum burst is the exceeded traffic. You can disable this by setting Maximum burst to the Normal burst value. Even like this you have exceed-action drop.

Yes using those values you are limiting the traffic to 3mbps. You can check your rate-limiting with show interface Fa0/0 rate-limit

Dan