Hi Hal, Sagi, > > On Sun, 2007-06-10 at 11:59, Sagi Schlanger wrote: > > Hi, > > > > I'm looking for some answers on Up-Down routing at OpenSM . > > > > Is anybody familiar with a utility/procedure to find credit loops > > given a topology and routing settings? > > I know there was at least talk of ibdiagnet (in ibutils) > checking this. > Not sure if it is implemented (yet) or if it is routing > algorithm independent. Eitan ? > > > Is there a handy spec describing the OpenSM Up-Down algorithm? > > The OpenSM up/down routing is based on the following paper: > > "Effective Strategy to Compute Forwarding Tables for > InfiniBand Networks" > Jose Carlos Sancho, Universidad Politécnica de Valencia > Antonio Robles, Universidad Politécnica de Valencia Jose > Duato, Universidad Politécnica de Valencia > > http://csdl2.computer.org/persagen/DLAbsToc.jsp?resourcePath=/ > dl/proceedings/&toc=comp/proceedings/icpp/2001/1257/00/1257toc > .xml&DOI=10.1109/ICPP.2001.952046 > > > What is the scheme through which roots are defined on clos and non > > clos/fat tree topologies? > > The admin can supply the roots via -a <guid_list_file> > option when invoking OpenSM. > > Auto-detect root nodes - based on the CA hop length > from any switch > in the subnet, a statistical histogram is built for > each switch (hop > num vs number of occurrences). If the histogram > reflects a specific > column (higher than others) for a certain node, then > it is marked as a > root node. Since the algorithm is statistical, it may > not find any root > nodes. The list of the root nodes found by this > auto-detect stage is > used by the ranking process stage. > > Note 1: The user can override the node list manually. > Note 2: If this stage cannot find any root nodes, > and the user did > not specify a guid list file, OpenSM > defaults back to the > Min Hop routing algorithm. > > > Is this algorithm always credit loop free? > YES IT IS > It's supposed to be. > > > How efficient is using this algorithm on non clos/fat tree > topologies? > > What do you mean by efficiency ? Also, are you asking about > pure fat tree or non pure fat tree (or both) ? > > -- Hal > > > Thanks for your cooperation, > > Sagi > > > > ____________________________________________________________ > > Sagi Schlanger | +972-9-9717651 (o) | +972-52-2385154 (m) > > Software Engineer, IB Switch > > Voltaire - The Grid Backbone > > > > www.voltaire.com > > > > > > > > > ______________________________________________________________________ > > > > _______________________________________________ > > general mailing list > > [email protected] > > http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general > > > > To unsubscribe, please visit > > http://openib.org/mailman/listinfo/openib-general > > _______________________________________________ > general mailing list > [email protected] > http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general > > To unsubscribe, please visit > http://openib.org/mailman/listinfo/openib-general > _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general
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