[c-nsp] Re: Traffic Shaping packet loss
Kanagaraj Krishna
kanagaraj at aims.com.my
Mon Sep 26 11:07:26 EDT 2005
Dan,
Now i can see how it works. The ping test was done from the 7206 (GigE
connected to the 2950). I realise that when a ping test is done from a PC,
there are no drop in packets. Will the traffic to the customer still be
effected?
For your info our customers given access are all below 2Mbps (64Kb, 512Kb
etc). Shaping on customers side is not an option because their side equipments
sometimes even consist of normal entry switch with no shaping capabilities.
Any other options available in fulfilling our objectives? Would policing on
the router sub-interface have the same effect?
Thanks.
> Charge them extra to set up shaping on their side.
>
> The problem, assuming it isn't something else, is that your pings are
> offering traffic at a faster rate then your rate limiting allows.
>
> This means bad things ahead for your customer's traffic and will make
> your service start to look crappy.
>
> Lets say, for instance, that on the physical 1 gig circuit you're
> offering some number of 10 meg and 100 meg rate limited connections to
> your customers.
>
> If their physical connections are at a gig that means their packets are
> arriving, already, at 10 times or a 100 times the contracted rate.
>
> The alternative to shaping might be to give your 10 meg customers a 10
> meg physical connection to you and your around a 100 meg customers a 100
> meg physical connection to you. This might help you put a nice little
> step in the monthly fees and give them a good feeling about paying for
> 100 meg when they actually get a 100 meg connection.
>
> If they are already on 10 or 100 meg connections and you're testing this
> on one end of a gig link to another and wondering why even pings are
> being dropped, ummm, I think you're beginning to see the light.
>
> -----Original Message-----
> From: Kanagaraj Krishna [mailto:kanagaraj at aims.com.my]
> Sent: Monday, September 26, 2005 8:35 AM
> To: Dan Martin
> Cc: cisco-nsp at puck.nether.net
> Subject: RE: [c-nsp] Re: Traffic Shaping packet loss
>
> Dan,
> Our customers co-locate with us and are directly connected to the
> switch.
> Its just that, we provide MRTG access to customers who want to monitor
> their
> traffic utilization. By setting the burst rate high, i don't want the
> customer
> to think they are getting more than they subscribed. Another thing is
> that for
> business reason, if the MRTG shows the traffic is hitting the cap (just
> say
> 64K and not more), we can ask them to upgrade. Any comments?
>
> Kana
>
> > Yes, you're right.
> >
> > This is a tough one to get, but your ping problem is a perfect
> teaching
> > tool.
> >
> > Think of it like this. take your packets per second setting and
> divide
> > it by a thousand, because I suck at math, lets say it's a thousand
> > packets per second. That means every millisecond, you have the right
> to
> > send one packet across that port. I know, its not in packets, its in
> > bytes, but bear with me for another moment.
> >
> > If two packets show up during that millisecond, one gets dropped. It
> > doesn't matter how many packets showed up the millisecond before or
> the
> > millisecond after.
> >
> > If you increase the burst size and your pings get through, that tells
> me
> > that there is not something else wrong, its only that your ping is
> > arriving at a higher rate than your contracted one.
> >
> > If you want to manage the bandwidth so tightly you should look into
> > traffic shaping on your customer's premises in order to match the
> > contract you're offering.
> >
> > -----Original Message-----
> > From: Kanagaraj Krishna [mailto:kanagaraj at aims.com.my]
> > Sent: Monday, September 26, 2005 8:03 AM
> > To: Dan Martin
> > Cc: cisco-nsp at puck.nether.net
> > Subject: RE: [c-nsp] Re: Traffic Shaping packet loss
> >
> > Dan,
> > I thought that the burst rate only takes into effect once the
> > average
> > speed limit is passed. Am i right?
> >
> > Quoting Dan Martin <dmartin at micromuse.com>:
> >
> > > So many per unit time.
> > >
> > > It doesn't wait a whole second and then pass or fail the stream.
> > >
> > > It divides a second into some number of parts, figures out how many
> > > packets or bytes should arrive during that part, and drops the rest.
> > >
> > > That is why your burst setting fixes the problem. You allow some
> > number
> > > of packets to arrive at a higher rate than contracted.
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: cisco-nsp-bounces at puck.nether.net
> > > [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Kanagaraj
> > > Krishna
> > > Sent: Monday, September 26, 2005 6:26 AM
> > > To: cisco-nsp at puck.nether.net
> > > Subject: [c-nsp] Re: Traffic Shaping packet loss
> > >
> > > Hi guys,
> > > I have a setup with a Catalyst 2950 connected to a GigE
> > port
> > > on 7206VXR. Sub-interfaces are configured on the GigE port for each
> > VLAN
> > > (dot1Q) that are assigned to each port in 2950. To control the
> > traffic,
> > > I've added the rate-limit command on the subinterface
> > >
> > > rate-limit input 64000 2000 2000 conform-action transmit
> exceed-action
> > > drop
> > > rate-limit output 64000 2000 2000 conform-action transmit
> > exceed-action
> > > drop
> > >
> > > It seems that when i do ping test, there are packet losses (even
> when
> > > the traffic is low). One thing I realised is that when the burst
> rate
> > is
> > > increased, the packet loss decreases. Any idea on why this happens?
> > >
> > > Regards,
> > > Kana
> > > _______________________________________________
> > > cisco-nsp mailing list cisco-nsp at puck.nether.net
> > > https://puck.nether.net/mailman/listinfo/cisco-nsp
> > > archive at http://puck.nether.net/pipermail/cisco-nsp/
> > >
> >
> >
> > --
> > Kanagaraj Krishna
> > Network Engineer
> > Network Engineering
> > Applied Information Management Services Sdn. Bhd.
> > (AIMS Sdn. Bhd.)
> > Ground Floor, Menara Aik Hua,
> > Changkat Raja Chulan,
> > 50200 Kuala Lumpur,Malaysia.
> >
> > Tel : +603-20314988 Ext : 395
> > Mobile : 012-3266151
> > Fax : +603-20318948
> > Email : kanagaraj at aims.com.my
> >
>
>
> --
> Kanagaraj Krishna
> Network Engineer
> Network Engineering
> Applied Information Management Services Sdn. Bhd.
> (AIMS Sdn. Bhd.)
> Ground Floor, Menara Aik Hua,
> Changkat Raja Chulan,
> 50200 Kuala Lumpur,Malaysia.
>
> Tel : +603-20314988 Ext : 395
> Mobile : 012-3266151
> Fax : +603-20318948
> Email : kanagaraj at aims.com.my
>
--
Kanagaraj Krishna
Network Engineer
Network Engineering
Applied Information Management Services Sdn. Bhd.
(AIMS Sdn. Bhd.)
Ground Floor, Menara Aik Hua,
Changkat Raja Chulan,
50200 Kuala Lumpur,Malaysia.
Tel : +603-20314988 Ext : 395
Mobile : 012-3266151
Fax : +603-20318948
Email : kanagaraj at aims.com.my
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