Re: [Idr] draft-litkowski-idr-bgp-timestamp

Sue your observation is valid however I have two comments to it:

*A* it does not apply to specifically crafted beacons as by such "special
crafting" you eliminate by design the expected variations.

*B* in general case you are right, but the general case is still broken if
timestamp is a property of the BGP path. Path may sit idle in BGP speaker
for minutes or hours and longer before at some event it is promoted as best
and send with say 30 min in/out delta falsely indicating potential problems
with given BGP speaker. And the way to eliminate that is *A* hence perhaps
just sticking to A is sufficient.

best regards,
R.

On Thu, Jul 24, 2014 at 8:50 PM, Susan Hares <shares@ndzh.com> wrote:

> Jon and Stephan:
>
> Based on work with vendor boxes for the BMWG BGP work - I would recommend
> you timestamp the BGP trace NLRI as you leave the BGP Peer and as you
> receive it. Otherwise, you run into the data flow patterns the trace NLRI
> is
> included in causing variation in your flows.
>
> Sue
>
> -----Original Message-----
> From: Idr [mailto:idr-bounces@ietf.org] On Behalf Of Jon Mitchell
> Sent: Tuesday, July 22, 2014 6:23 PM
> To: stephane.litkowski@orange.com
> Cc: Jeffrey Haas; idr wg; Robert Raszuk
> Subject: Re: [Idr] draft-litkowski-idr-bgp-timestamp
>
> On 22/07/14 22:00 +0000, stephane.litkowski@orange.com wrote:
> > Hi Jon,
> >
> > Thanks for your comment.
> > Regarding packing, depending of the address family you are trying to
> monitor, current packing may be low or high. In case where existing packing
> is low, it does not change anything. In case packing is high, yes I agree
> that the processing of the update is a bit changed and my beacon would be
> sent may be faster. Packing is introducing slight delay but I don't think
> delay introduced by packing is a major component expect if an
> implementation
> get stucks in packing (it may happen but I never seen it). IMHO, I don't
> think this is a critical point but I'm open to other opinions.
> >
> > Now for BMP, we are not targeting to monitor our beacons on all PEs, just
> a subset of representative.
> > Moreover it's not only a question about number of sessions, it's a
> question of ordering the information retrieved. If you consider using BMP ,
> the tool will peer with selected PEs, but also "transit BGP Speakers"
> (ASBRs, RRs ...). When the tool will receive the timestamp information (if
> implementation of BMP supports timestamp), it requires to sort and
> reorganize the received information based on the knowledge of the topology
> :
> you cannot just sort by timestamp, you have to find relationship between
> BGP
> Speakers (information from BMP and topology) and combine them to recreate
> our timestamp vector. BGP transport permits to create automatically this
> timestamp vector without having to implement a complex machinery in the
> tool. But BMP can be used at the selected PE to the tool to retrieve
> timestamp vectors.
> >
>
> Stephane - yes, I think this second point is the real object of the draft
> (correct me if I'm wrong).  Offline correlation engines are complicated to
> implement and/or expensive, although commercially available.  Getting the
> timestamp data seems not to be the real issue here at all (via BMP or other
> mechanisms a local implementation can provide).  Maybe this point should be
> more clear in the intro and text.
>
> Jon
>
> _______________________________________________
> Idr mailing list
> Idr@ietf.org
> https://www.ietf.org/mailman/listinfo/idr
>
>