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

[<[e-mail]>]

Georgios

- it would have been very useful to have raised this last week at IETF. Progress is so much easier face to face.
- are you talking about admission or termination? I got confused; your emails didn't seem consistent.
- I haven't read all the emails in detail, but I don't understand what are you saying that's different from http://www.ietf.org/internet-drafts/draft-charny-pcn-comparison-00.txt ?  eg Table 8.1 extract:
    -------------------------------------------------------------------|
   |Comparison    |      SM       |       3SM        |      CL         |
   |criteria      |               |                  |                 |
   |--------------------------------------------------------------------
   |-------------------------------------------------------------------|
   |ECMP support  |no;   only     |     yes          | no;  but full   |
   |for           |partial support|                  | support with    |
   |Termination   |with additional|                  | additional      |
   |              | complexity at |                  | complexity at   |
   |              | the edge +    |                  | the edge +      |
   |              | signaling flow|                  | plus signalling |
   |              | flow IDs from |                  | flow IDs from   |
   |              | egress to     |                  | egress to       |
   |              | ingress       |                  | ingress         |
   |-------------------------------------------------------------------|
   |ECMP support  |no w/out probes| no w/out probing | no w/out probing|
   |for Admission |yes with probes| yes with probing | yes with probing|
   |              |but needs many |(needs one probe, |(needs one probe,|
   |              |probes; use of |can use RSVP as   | can use RSVP    |
   |              |RSVP as probes |probe)            | as probe)       |
   |              |not understood |                  |                 |
   |-------------------------------------------------------------------|

- you seem to be saying that preferential dropping of excess-rate-marking pkts in your view can lead to problems - and proposing instead random dropping, but saying this can also lead to the same problem (but maybe not as often). Is that right?

best wishes,
phil

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf Of
> Geib, Ruediger
> Sent: 19 March 2008 13:42
> To: [e-mail]
> Cc: [e-mail]
> Subject: Re: [PCN] Concensus questions from Thursday's PCN meeting
> 
> Hi Georgios,
> 
> I assume the costs to marginal as compared to the expenditure
> required to avoid these losses. We face tough regulation and
> can't stay in business if we engineer networks for resilience
> during catastrophic outages. These times are gone.
> 
> During catastrophic outages, my operational staff will require
> good OAM tools to enable return to bearable operation as soon
> as possible. To me, OAM is the only section in PCN drafts
> I'd like to be addressed to deal with catastrophic outages.
> 
> Regards
> 
> Rudiger
> 
> | -----Original Message-----
> | From: Georgios Karagiannis [mailto:[e-mail]]
> | Sent: Wednesday, March 19, 2008 2:21 PM
> | To: Geib, Rüdiger
> | Cc: [e-mail]
> | Subject: RE: [PCN] Concensus questions from Thursday's PCN meeting
> |
> | 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:[e-mail]]
> | > Sent: woensdag 19 maart 2008 14:17
> | > To: [e-mail]
> | > Cc: [e-mail]
> | > 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:[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]
> | > | > | > |
> | > | > | > |
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> | > | > | >
> | > | > |
> | > | > |
> | > | > |
> | > | >
> | > |
> | > |
> | > |
> | >
> |
> |
> |
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