From: Anthony Pace (anthonypace@fastmail.fm)
Date: Fri Nov 21 2003 - 12:29:33 GMT-3
If shaping is ont during times of non-congestion then how does it differ
from policing in the scenario below? Why ot just polic it if you want a
strict cap on bandwidth?
Tony
On Wed, 8 Oct 2003 17:15:49 -0500, "Mike Williams" <ccie2be@swbell.net>
said:
> Not neccesarily true... If you use GTS on an interface, then (AFAIK) it
> will only kick in when there is congestion, but if you apply shaping
> using a policy map (i.e. class-based shaping), the shaping "creates a
> false congestion" whenever the that traffic class exceeds the values you
> use on the shaping command (this was told to me by a group of Cisco
> SE's) and then actively shapes the traffic. I configured the policy to
> shape certain traffic down to 8Kbps, and it works like a charm
> regardless of whether the interface was congested or not. Furthermore,
> my testing was also done on an ethernet interface, and this was a 3600
> router (not really "high-end"). In my testing, we were trying to limit
> the bandwidth used by a VPN tunnel. Since we knew the IP address of
> each endpoint, I just made an access-list, made a class that matched
> that ACL, then made a policy that only affected that class. Since you
> can only shape on traffic going out of an interface, I had to apply this
> shaping to the FastEthernet interface (instead of the ATM interface).
> Like I said, it worked like a charm, and I could see that it was
> actively shaping the traffic down to 8Kbps, as well as how many packets
> were delayed, dropped, etc...
>
> Mike W.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> asadovnikov
> Sent: Wednesday, October 08, 2003 5:51 AM
> To: 'Hunt Lee'; ccielab@groupstudy.com
> Subject: RE: Which one should I pick ?
>
>
> The way you put the question makes policing the only choice. Either a
> police statement as you specified, or older CAR will do. Shaping only
> kicks in during congestion periods and is not in effect unless a
> congestion is present.
>
> Further I do not believe shaping is supported on Ethernet (some higher
> end boxes to have additional QOS implemented in hardware).
>
> Best regards,
> Alexei
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Hunt Lee
> Sent: Tuesday, October 07, 2003 10:06 PM
> To: ccielab@groupstudy.com
> Subject: Which one should I pick ?
>
>
> If I have a question:
>
> Configure CBWFQ on R1's Ethernet interface such that it allocates min
> bandwidth of 3mbps for VLANA. VLANA traffic should limit to 5mbps and
> cannot utilize more physical bandwidth during non-congestion period.
>
> Should I use:
>
> policy-map cbwfq
> class VLAND
> bandwidth 3000
> shape peak 5000000
>
> OR
>
> policy-map cbwfq
> class VLAND
> bandwidth 3000
> police 5000000 937500 1875000 conform-action transmit exceed-action
> drop violate-action drop
>
> And if you could give me reasoning on why you pick that one, it would be
> greatly appreciated.
>
> Thank you so much in advance,
> H.
>
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-- Anthony Pace anthonypace@fastmail.fm-- http://www.fastmail.fm - Accessible with your email software or over the web
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