Re: [nsp] Rate Limiting

From: Dave O'Meara (dave.omeara@eircom.net)
Date: Fri Jan 12 2001 - 07:02:13 EST


As a related issue, does anyone have any good advice on setting these
burst values? I have only found one paper on the Cisco website,
recommending that the initial burst be approx 1 - 1.5 seconds worth of
data, with the extended burst around twice that.

Any input?

Dave

Bremen K H Lee wrote:
>
> Hi Ramos,
>
> In fact CAR allow you to burst. Below is an abstract from the Cisco web
> page
> http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/qos_c
> /qcpart1/qccar.htm
>
> "In this example, a customer is connected to an Internet service provider
> (ISP) by a T3 link. The ISP wants to rate limit the customer's transmissions
> to 20 Mbps of the 45 Mbps. In addition, the customer is allowed to transmit
> bursts of 24000 bytes. All exceeding packets are dropped. The following
> commands are configured on the ISP's High-Speed Serial Interface (HSSI)
> connected to the customer:
>
> interface Hssi0/0/0
> description 45Mbps to R1 rate-limit input 20000000 24000 24000
> conform-action transmit exceed-action drop
> ip address 200.200.14.250 255.255.255.252
> rate-limit output 20000000 24000 24000 conform-action transmit exceed-action
> drop"
>
> Cheers,
>
> Bremen
>
> -----Original Message-----
> From: Ramos, Armand G. [mailto:RamosAG@etpi.com.ph]
> Sent: Friday, January 12, 2001 10:53 AM
> To: cisco-nsp@puck.nether.net
> Cc: bgreene@cisco.com
> Subject: [nsp] Rate Limiting
> Importance: High
>
> Good Day to you all,
>
> I would just like to seek your expertise on how I could implement a set-up
> for my customers.
>
> I am providing a shared access of 1:4 for my customers for every single pipe
> link. Theoretically, our set-up should work like this: if I have a pipe of
> 64Kbps upstream, with the 1:4 contention ratio, I would be able to service
> up to four 64Kbps customers. Basically, they are guaranteed 1/4 (25%) of
> their subscribed bandwidth with us and has a possibility of burst to a 100%
> on the occassion that the other 3 customers are not using link.
>
> However, as we were implementing it, customers traffic are not symmetric
> than we expect. What happened was, one of the 4 sharing customers would
> basically eating up the whole pipe with the others having difficulty passing
> through. We tried implementing CAR on these customer but all it does is peg
> their bandwidth and does not give the ability to burst during non-peak.
>
> Is there a proper set-up or configuration that we could implement to achieve
> the desired specs for our service. Hope I hear soon from you guys.
>
> More power!!!
>
> Best regards,
>
> Armand Ramos



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