At 02:47 PM 2/12/2007, Sean Hefty wrote: > > 1) What does the TClass and FlowLabel returned from SGID=local > > DGID=remote mean? > > Do you use it in the Node1 -> Node2 direction or the Node2 -> Node1 > direction > > or both? > >Maybe it would help if we can agree on a set of expectations. These are >what I >am thinking: > >1. An SA should be able to respond to a valid PR query if at least one of the >GIDs in the path record is local. > >2. The LIDs in a PR are relative to the SA's subnet that returned the record. > >3. An IB router should not failover transparently to QPs sending traffic >through >that router.
There is no reason for such a restriction. APM can work with routers and the IB protocol will recover from any out of order packet processing just fine. >4. A PR from the local SA with reversible=1 indicates that data sent from the >remote GID to the local GID using the PR TC and FL will route locally >using the >specified LID pair. This holds whether the PR SGID is local or remote. > >5. A PR from a remote SA with reversible=1 indicates that data sent from the >local GID to the remote GID using the PR TC and FL will route remotely >using the >specified LID pair. This holds whether the PR SGID is local or remote. > >6. A PR with reversible=0 is relative to SA's subnet. The SGID->DGID data >flow >over the PR TC and FL indicates the SLID->DLID mapping for that subnet. > >Do your expectations differ from these? > >The use of reversible between subnets is what's concerning me. It may be >that >an SA could not return any paths as reversible between two subnets without >using >some trick like what you mentioned. > >These add a requirement on the SA that they must be aware of the routes >packets >take between two GIDs using a given TC and FL, but I don't believe that this >necessarily forces SA to SA communication. The SA may only need to exchange >information with a router...? It should not force SA to SA communication. Such communication is overly complex and will be a major issue to control and manage in the end. Further, security concerns, partition management, etc. start to complex enough as it is without adding more fuel to the fire. > > Implicit in this are five IBA affecting things: > > - that PRs with SGID=non-local mean something specific > >I don't think that we're changing any of the meanings of the fields though. > > > - Routers do the SLID spoofing you outlined. > >I'm not sure this is something that we do want now. APM should really handle >path failover. > > > There is alot of complex work in the router and SA side to make this > > kind of topology work, but it is critical that the clients use path > > queries that can provide enough data to the SA and return enough data > > to the client to support this. > >I'm still deciding if the existing path record attribute is sufficient. Our original IB router work I believe drove some of what is in the current records so I suspect they are fine as is. Mike _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
