Date: Sun, 11 Mar 2001 20:33:12 -0700 From: "alex huppenthal" <alex@aspenworks.com> To: "Tom Samplonius" <tom@sdf.com> Cc: <freebsd-isp@FreeBSD.ORG> Subject: Re: ATM and traffic shaping Message-ID: <002201c0aaa5$2ac56840$1900a8c0@aspenworks.com> References: <Pine.BSF.4.05.10103111806400.9461-100000@misery.sdf.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Tom,
Thanks for the response.
I have a Lucent PSAX switch. I'll check to see if buffering is available.
If it is, then a combination of IP throughput management plus buffering in
the PSAX should work. Bursts of max-buf-len bytes will drop into the switch
and the switch would pace the outbound cell rate.
Just checked.. There is a bit of a problem, the PSAX DS3 card will not do
traffic shaping. I'm screwed. I have a channelized DS3 also, but there's no
way to configure it to make it clear channel, with traffic shaping. Yikes!
I'm going to dump it all and call for IP over Sonet. Anyone know of dark
fiber between Glenwood Springs, CO and Denver?
:-)
oh, there must be a way..
----- Original Message -----
From: "Tom Samplonius" <tom@sdf.com>
To: "Alex Huppenthal" <alex@aspenworks.com>
Cc: <freebsd-isp@FreeBSD.ORG>
Sent: Sunday, March 11, 2001 7:17 PM
Subject: Re: ATM and traffic shaping
>
> On Sun, 11 Mar 2001, Alex Huppenthal wrote:
>
> > It turns out that traffic shaping for ATM means being able to delay each
> > cell to a specific egress ('transmit' in english) rate.
>
> Yes, exactly. And many switches are configured to drop non-conforming
> cells (cells that exceed the allowable cell-per-second rate). I wouldn't
> recommend that anyone attempt ATM without understanding all the service
> categories and parameters.
>
> However, it somewhat depends on the category of service that you
> receive. There are lots of possibilities: ubr, cbr, rt-vbr, nrt-vbr, and
> vbr. The maximum cell rate isn't always a simple thing, as they interact
> with the mcr, pcr, mbs, and scr parameters.
>
> Since you are using your own ATM switch, I'm surprised that you can't
> let your switch buffer cells for you, rather than discard them. For
> instance, if your ATM provider has given you a cbr service with 10K
> cells/second rate, just let FreeBSD run ubr into the switch.
>
> But it really depends on your ATM service provider. I have a very
> expensive switch with an ATM card and multiple ethernet ports. My ATM
> service provider is providing an abr with a pcr of 10Mbps service. Their
> switch will buffer and pace out traffic for me, so I have the link setup
> as ubr on my end. In fact, it was the configuration they recommended.
>
> Tom
>
>
> To Unsubscribe: send mail to majordomo@FreeBSD.org
> with "unsubscribe freebsd-isp" in the body of the message
>
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-isp" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?002201c0aaa5$2ac56840$1900a8c0>