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Re: [PCN] "blind marking" not a big advantage

<philip.eardley@bt.com> Mon, 25 February 2008 11:35 UTC

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Thread-Topic: [PCN] "blind marking" not a big advantage
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From: philip.eardley@bt.com
To: menth@informatik.uni-wuerzburg.de, pcn@ietf.org
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Subject: Re: [PCN] "blind marking" not a big advantage
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In terms of 3SM edge behaviour [the 3rd of the 4 columns below), then
termination marked packets are metered.

For CL edge behaviour [the 4th of the 4 columns below), then including
termination marked packets can lead to over-termination in multiple
bottleneck scenarios. 
Possibly this is a trade-off work making? Ie simpler behaviour for
PCN-interior-node for more complexity in edges or more uncertainty in
outcome of termination?



> -----Original Message-----
> From: pcn-bounces@ietf.org [mailto:pcn-bounces@ietf.org] On Behalf Of
> Michael Menth
> Sent: 25 February 2008 10:32
> To: pcn
> Subject: [PCN] "blind marking" not a big advantage
> 
> Hi,
> 
> I have seen that some encoding discussions underlined the benefit of
> "blind marking", i.e. the codepoint can be set without reading the ECN
> bits before. I just want to point out that this advantage is not so
big
> because the meter needs to know the marking anyway to avoid that
> termination marked packets are metered. I just copied from the
> comparison draft
> http://www.ietf.org/internet-drafts/draft-charny-pcn-comparison-00.txt
> 
>
|-------------------------------------------------------------------|
>    |Metering and  | do not meter  |  meter all pkts  | do not meter
|
>    |remarking of  | AM-marked     |  for admission   | TM-marked pkts
|
>    |previously    | packets       |  and termination;| for termination
|
>    |marked        |               |  do not re-mark  | meter all
pkts;|
>    |packets       |               |  TM-marked pkts  | for admission,
|
>    |              |               |                  | do not re-mark
|
>    |              |               |                  | TM-marked pkts
|
>
|-------------------------------------------------------------------|
> 
> 
> Regards,
> 
>     Michael
> 
> --
> Dr. Michael Menth, Assistant Professor
> University of Wuerzburg, Institute of Computer Science
> Am Hubland, D-97074 Wuerzburg, Germany, room B206
> phone: (+49)-931/888-6644, fax: (+49)-931/888-6632
> mailto:menth@informatik.uni-wuerzburg.de
> http://www3.informatik.uni-wuerzburg.de/research/ngn
> 
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