Re: [PCN] Concensus questions from Thursday's PCN meeting

"Georgios Karagiannis" <karagian@cs.utwente.nl> Wed, 19 March 2008 13:23 UTC

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From: Georgios Karagiannis <karagian@cs.utwente.nl>
To: "'Geib, Ruediger'" <Ruediger.Geib@t-systems.com>
References: <BABC859E6D0B9A4D8448CC7F41CD2B0706181835@xmb-rtp-203.amer.cisco.com><RrmbUrJK.1205679770.1867150.karagian@ewi.utwente.nl><1B6169C658325341A3B8066E23919E1CF641B0@S4DE8PSAANK.mitte.t-com.de><000001c88809$b2e73840$810c5982@dynamic.ewi.utwente.nl><1B6169C658325341A3B8066E23919E1CF6423C@S4DE8PSAANK.mitte.t-com.de><001301c88816$114dab60$810c5982@dynamic.ewi.utwente.nl><1B6169C658325341A3B8066E23919E1CF644B1@S4DE8PSAANK.mitte.t-com.de><000001c88835$998bcf60$810c5982@dynamic.ewi.utwente.nl><1B6169C658325341A3B8066E23919E1CF6451A@S4DE8PSAANK.mitte.t-com.de><000601c8883b$e3828950$810c5982@dynamic.ewi.utwente.nl><1B6169C658325341A3B8066E23919E1CF64580@S4DE8PSAANK.mitte.t-com.de><000901c88844$f35c1130$810c5982@dynamic.ewi.utwente.nl><1B6169C658325341A3B8066E23919E1CF645A3@S4DE8PSAANK.mitte.t-com.de><000a01c8884d$081c9790$810c5982@dynamic.ewi.utwente.nl><1B6169C658325341A3B8066E23919E1CF64645@S4DE8PSAANK.mitte.t-com.de><1205849919.9521.7.camel@neutrino> <1B6169C658325341A3B8! ! ! ! ! 066E23919E1CF 64B8A@S4DE8PSAANK.mitte.t-com.de> <002901c889b5$ad4671a0$810c5982@dynamic.ewi.utwente.nl> <1B6169C658325341A3B8066E23919E1CF64C3B@S4DE8PSAANK.mitte.t-com.de> <003501c889bd$b07549c0$810c5982@dynamic.ewi.utwente.nl> <1B6169C658325341A3B8066E23919E1CF64CCF@S4DE8PSAANK.mitte.t-com.de>
Date: Wed, 19 Mar 2008 14:21:11 +0100
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Cc: pcn@ietf.org
Subject: Re: [PCN] Concensus questions from Thursday's PCN meeting
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Hi Ruediger

I do not know, but when such an event occurs, what are then the costs
involved associated with the financial losses 
and customer losses for an operator of a large network with a huge number of
subscribers?

Best regards,
Georgios



> -----Original Message-----
> From: Geib, Ruediger [mailto:Ruediger.Geib@t-systems.com] 
> Sent: woensdag 19 maart 2008 14:17
> To: karagian@cs.utwente.nl
> Cc: pcn@ietf.org
> Subject: RE: [PCN] Concensus questions from Thursday's PCN meeting
> 
> Hi Georgios,
> 
> could you give us an estimate of the propability that this 
> problem occurs? How often within a year?
> 
> Regards,
> 
> Rudiger
>  
> 
> | -----Original Message-----
> | From: Georgios Karagiannis [mailto:karagian@cs.utwente.nl]
> | Sent: Wednesday, March 19, 2008 1:35 PM
> | To: Geib, Rüdiger
> | Cc: pcn@ietf.org
> | Subject: RE: [PCN] Concensus questions from Thursday's PCN meeting
> | 
> | 
> |  Hi Ruediger
> | 
> | It is not a new solution! What I describe are problems that 
> are in my 
> | opinion occuring when the PCN domain uses ECMP routing, AND when a 
> | catastrophic event occurs AND when marked packets are 
> preferentially 
> | dropped.
> | The only thing that I am trying to say, is PLEASE DO NOT 
> mandate the 
> | preferentially dropping of  marked packets, such that we can avoid 
> | such difficult and nasty problems.
> | 
> | I am not proposing here another solution.
> | 
> | 
> | Best regards,
> | Georgios
> | 
> | > -----Original Message-----
> | > From: Geib, Ruediger [mailto:Ruediger.Geib@t-systems.com]
> | > Sent: woensdag 19 maart 2008 13:06
> | > To: karagian@cs.utwente.nl
> | > Cc: pcn@ietf.org
> | > Subject: RE: [PCN] Concensus questions from Thursday's PCN meeting
> | > 
> | > Hi Georgios,
> | > 
> | > with how many operator representatives involved into
> | backbone traffic
> | > engineering including activation of ECMP did you talk prior to 
> | > proposing your solution on this mailing list?
> | > 
> | > Regards,
> | > 
> | > Rudiger
> | > 
> | > 
> | > | -----Original Message-----
> | > | From: Georgios Karagiannis [mailto:karagian@cs.utwente.nl]
> | > | Sent: Wednesday, March 19, 2008 12:38 PM
> | > | To: Geib, Rüdiger; steven.blake@ericsson.com
> | > | Cc: pcn@ietf.org
> | > | Subject: RE: [PCN] Concensus questions from Thursday's 
> PCN meeting
> | > | 
> | > | Hi Rudeiger
> | > | 
> | > | What I am proposing is how to achieve a robust/stable PCN
> | operation
> | > | when the PCN domain uses ECMP routing and when a
> | catastrophic event
> | > | occurs.
> | > | 
> | > | Best regards,
> | > | Georgios
> | > | 
> | > | 
> | > | 
> | > |  
> | > | 
> | > | > -----Original Message-----
> | > | > From: pcn-bounces@ietf.org [mailto:pcn-bounces@ietf.org] On
> | > | Behalf Of
> | > | > Geib, Ruediger
> | > | > Sent: woensdag 19 maart 2008 11:37
> | > | > To: steven.blake@ericsson.com
> | > | > Cc: pcn@ietf.org
> | > | > Subject: Re: [PCN] Concensus questions from Thursday's
> | PCN meeting
> | > | > 
> | > | > Steven,
> | > | > 
> | > | > what Georgios is proposing is to optimise PCN so that 
> it works 
> | > | > properly if a catastrophic event coincides with a 
> misconfigured 
> | > | > router.
> | > | > 
> | > | > If this is the main or even an important task of PCN, then
> | > | I waste my
> | > | > time here.
> | > | > 
> | > | > The salary I obtain monthly depends on my companies
> | > | backbone network
> | > | > providing good service to customers under regular operational 
> | > | > conditions (which cover planned outages and expectable
> | > | failures). The
> | > | > telephony or streaming services offered to our 
> customers should 
> | > | > experience a minimised network impact on the Quality of
> | > Experience
> | > | > perceived by the consumers under regular operational
> | > | conditions. This
> | > | > includes the creation of a "Network Busy Indication", which
> | > | however is
> | > | > a rare event. So my position on what PCN should be
> | > | optimised for is to
> | > | > create this "network busy indication" for regular operational 
> | > | > conditions, reliably and only if it is required.
> | > | > This should be done with the least possible complexity
> | > | (like the least
> | > | > possible flow awareness, the least codepoint
> | consumption, simple
> | > | > queuing/policing and measurement functions, utmost re-use
> | > | of allready
> | > | > implemented features).
> | > | > 
> | > | > To clarify what I mean by a rare event: a well engineered
> | > backbone
> | > | > creating a PCN network busy indication either during a
> | > main traffic
> | > | > hour or after a re-routing event. During ISDN times,
> | engineering
> | > | > resulted in what Americans called 5ESS switches, aiming on
> | > | a network
> | > | > busy indication probability of (100 - 99,999%, the 5
> | > nines). We may
> | > | > see that a bit more relaxed for IP networks, but I don't
> | > think the
> | > | > customers of my company should experience the
> | consequences of PCN
> | > | > behaviour more often than in (100 - 99,x)%.
> | > | > 
> | > | > I don't look at PCN as a replacement of network
> | > engineering, it is
> | > | > rather an add on to guarantee service quality of admitted
> | > users by
> | > | > stopping admission of new traffic once engineering reaches
> | > | its limits. 
> | > | > Under regular operational conditions.
> | > | > 
> | > | > If someone now answers to this mail: uhh, just that - easy!
> | > | > Then lets move this easy thing to WGLC. Now. I can't see that.
> | > | > 
> | > | > If the PCN WG indeed has completely different aims, then
> | > | I'm sorry for
> | > | > bothering you with my mails (but I wonder whether I'm the
> | > | one having
> | > | > gotten things wrong).
> | > | > 
> | > | > By the way, I'm happy with the progress visible in the
> | > | questions you /
> | > | > the WG has formulated. That looks like a constructive 
> approach.
> | > | > 
> | > | > Regards,
> | > | > 
> | > | > Rudiger
> | > | > 
> | > | > 
> | > | > 
> | > | > | -----Original Message-----
> | > | > | From: Steven Blake [mailto:steven.blake@ericsson.com]
> | > | > | Sent: Tuesday, March 18, 2008 3:19 PM
> | > | > | To: Geib, Rüdiger
> | > | > | Cc: pcn@ietf.org
> | > | > | Subject: Re: [PCN] Concensus questions from Thursday's
> | > PCN meeting
> | > | > | 
> | > | > | On Tue, 2008-03-18 at 08:29 +0100, Geib, Ruediger wrote:
> | > | > | 
> | > | > | > Hi Georgios,
> | > | > | > 
> | > | > | > in the situation you describe, packet losses occur. This
> | > | > | will result
> | > | > | > in bad press, as the customers using PCN based services
> | > | > | were promised
> | > | > | > another type of service.
> | > | > | > 
> | > | > | > In this situation it doesn't matter whether or not ECMP
> | > | > is deployed
> | > | > | > and it also doesn't matter whether termination is fair or
> | > | > not. The
> | > | > | > important event is: packet losses occur (in one of your
> | > | examples
> | > | > | > several routers drop packets). The drops are the only
> | > | > | relevant issue.
> | > | > | > Whether service resumes after 5 seconds due to
> | extremly well
> | > | > | > engineered termination or after 10 seconds after a
> | > | > | sufficient number
> | > | > | > of customers hang up is not important.
> | > | > | > I can't recall having read anytime in the news "Major
> | > | > | network outage -
> | > | > | > but termination was fair." I can only recall having seen
> | > | > the first
> | > | > | > part.
> | > | > | > 
> | > | > | > I'm sure you're happy in adapting your example, as you
> | > | do all the
> | > | > | > time. I'm having work to do, but maybe someone else is
> | > | > | interested in
> | > | > | > continuing discusion. I think, I've made my point.
> | > | > | 
> | > | > | Ruediger,
> | > | > | 
> | > | > | If I follow this comment to its logical conclusion,
> | then PCN is
> | > | > | superfluous in this network.  Is that what you are
> | > trying to say?
> | > | > | 
> | > | > | 
> | > | > | Regards,
> | > | > | 
> | > | > | =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> | > | > | Steven Blake                <steven.blake@ericsson.com>
> | > | > | Ericsson/Redback Networks               +1 919-472-9913
> | > | > | 
> | > | > | 
> | > | > _______________________________________________
> | > | > PCN mailing list
> | > | > PCN@ietf.org
> | > | > https://www.ietf.org/mailman/listinfo/pcn
> | > | > 
> | > | 
> | > | 
> | > | 
> | > 
> | 
> | 
> | 
> 


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