On Mon, 21 Nov 2011 09:05:22 -0800 "Hefty, Sean" <[email protected]> wrote:
> > From what I understand, and I may not understand correctly, to > > perform IB Multicast, betweeen two nodes, I need to swap addresses and > > remote keys for the two nodes. In the examples I have seen this has > > You only need to do this for unicast UD. Multicast doesn't require > exchanging addresses and qkeys, but see below. > > > been done via RDMA CM directly between the two nodes. Does it matter > > how this information is exchanged? In my application I will have > > For multicast, you need to 1. have the SA create the multicast group and 2. > join the group. To create the group, you need to either have the SA > automatically create the group (if this is possible) or create it > dynamically. To create the group dynamically from user space, you should use > the rdma_cm or ib_umad interfaces. The rdma_cm is easier. > FWIW, OpenSM (current master branch) now has the ability to create multicast groups at startup, so 1 is possible. See: http://www.spinics.net/lists/linux-rdma/msg10021.html Ira > To join the group, you need to let the SA know that the node should receive > multicast traffic, so that it can program the switches. This is done through > the rdma_cm (easy way) or using ib_umad (hard way that gets harder if you > want to support multiple applications joining the same group from the same > system). > > > several nodes multicasting to several other nodes and I want to manage > > the connections from a independent application. What I would like to > > do is write this application, server, etc. so that each node would > > request connection with another node and then be provied with the > > information it needs to multicast. For example... Node 1 would > > request a connection (from the server app) Node 2 and Node 2 would > > request a connection (again, from the server app) to Node 1. The > > Server app would provide Node 2's "credentials" to Node 1 and likewise > > to Node 2. Is this even possible? > > The SA basically does the work that you're describing for your server app. > Node 1 can ask the SA to create a multicast group. Node 2 can ask to join > that group. Somehow node 2 needs to know what group node 1 created. > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Ira Weiny Member of Technical Staff Lawrence Livermore National Lab 925-423-8008 [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
