[cisco-bba] To Shape or Police DSL Subscribers ??

[Tony]

Hi Andy,

My $0.02 is to just police it. If they're plain old DSL connections don't waste the resources on shaping them, even if it does seem minute now.

You'll also find that the more TCP sessions you have over the same link the smoother the graph will look with policing.

Not sure what you're doing the testing with, but I'd suggest iperf and then look at the difference between using one simultaneous thread and 10 (iperf option "-P 10"). The more threads you have, the smoother it will get, even with policing. This is due to the way TCP works so that when a packet gets "lost" it backs off a little which is why you see a typical "sawtooth" graph for TCP sessions.

Alternatively you can test with UDP packets (iperf option "-u") and fire as much traffic as you want at your shaper (ie. 10Mbps if you like !). What escapes through the policer should be a fairly steady stream at your policing limit as UDP has no concept of flow control. 



regards,
Tony.


--- On Mon, 7/9/09, Arie Vayner <arievayner at gmail.com> wrote:

> From: Arie Vayner <arievayner at gmail.com>
> Subject: Re: [cisco-bba] To Shape or Police DSL Subscribers ??
> To: "Andy Saykao" <andy.saykao at staff.netspace.net.au>
> Cc: cisco-bba at puck.nether.net
> Received: Monday, 7 September, 2009, 5:05 PM
> So from the performance point of view, you
> would see a hit if you use many shapers on the software
> based boxes (7301/7200). On ASR it should be better.
> I have seen many ISPs use policing, and it worked just
> fine.
> 
> 
> 
> Arie
> 
> On Mon, Sep 7, 2009 at 10:03 AM,
> Andy Saykao <andy.saykao at staff.netspace.net.au>
> wrote:
> 
> 
> 
> 
> 
> 
> 
> Hi Arie,
>  
> We have a mixture of 7301's, 7200
> VXR's and ASR 
> 1004.
>  
> Cheers.
>  
> Andy
> 
> 
> 
> From: Arie Vayner
> [mailto:arievayner at gmail.com]
> 
> 
> Sent: Monday, 7 September 2009 5:02 PM
> To: Andy 
> Saykao
> Cc: cisco-bba at puck.nether.net
> Subject: Re: 
> [cisco-bba] To Shape or Police DSL Subscribers ??
> 
> 
> Andy,
> 
> One thing about shaping is that it takes more resources 
> (mainly CPU) from the router.
> What kind of a router is 
> that?
> 
> Arie
> 
> 
> On Mon, Sep 7, 2009 at 9:41 AM,
> Andy Saykao <andy.saykao at staff.netspace.net.au>
> 
> wrote:
> 
> 
>   
>   Hi
> All,
>    
>   Is it better to
> shape or police DSL 
>   subscribers that have exceeded their quota or does it not
> matter which method 
>   you choose? We are currently using 
>   CoA with policing but I've been asked to investigate
> whether we should look at 
>   shaping instead of policing. My testing reveals that
> policing is more bursty 
>   as seen below. 
>    
>   *** Example with
> Policing 
>   ***
>    
>   policy-map
> POLICE-TEST
>   class 
>   class-default
>    police 48000 9000 18000    
>   conform-action transmit     exceed-action 
>   drop     violate-action drop
>    
>   Using:
> cisco-avpair = 
>  
> "ip:sub-qos-policy-out=POLICE-TEST"
>   
> 
>   Download speeds
> fluctuate between 5.2 - 
>   7.6KB/sec. More bursty.
>    
>   *** Example with
> Shaping 
>   ***
>    
>   policy-map
> SHAPE-TEST
>   class 
>   class-default
>     shape average 
> 48000
> 
>   Using:
> cisco-avpair = 
>  
> "ip:sub-qos-policy-out=SHAPE-TEST"
>    
>   
>   Download speeds
> remain 
>   at constant 5.6KB/sec. Very little 
>   bursting.
>    
>   Any pro's and
> con's to either 
>   method???
>    
>   Thanks.
>    
>   Andy


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