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

["Geib, Ruediger" <[e-mail]>]

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:[e-mail]] 
| Sent: Wednesday, March 19, 2008 1:35 PM
| To: Geib, Rüdiger
| Cc: [e-mail]
| 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:[e-mail]]
| > Sent: woensdag 19 maart 2008 13:06
| > To: [e-mail]
| > Cc: [e-mail]
| > 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:[e-mail]]
| > | Sent: Wednesday, March 19, 2008 12:38 PM
| > | To: Geib, Rüdiger; [e-mail]
| > | Cc: [e-mail]
| > | 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: [e-mail] [mailto:[e-mail]] On
| > | Behalf Of
| > | > Geib, Ruediger
| > | > Sent: woensdag 19 maart 2008 11:37
| > | > To: [e-mail]
| > | > Cc: [e-mail]
| > | > 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:[e-mail]]
| > | > | Sent: Tuesday, March 18, 2008 3:19 PM
| > | > | To: Geib, Rüdiger
| > | > | Cc: [e-mail]
| > | > | 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                <[e-mail]>
| > | > | Ericsson/Redback Networks               [phone]
| > | > | 
| > | > | 
| > | > _______________________________________________
| > | > PCN mailing list
| > | > [e-mail]
| > | > https://www.ietf.org/mailman/listinfo/pcn
| > | > 
| > | 
| > | 
| > | 
| > 
| 
| 
| 
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