Quoting r. Hal Rosenstock <[EMAIL PROTECTED]>: > Subject: Re: IB Address Translation service > > Reviving an old thread... > > On Sat, 2005-03-05 at 10:22, David M. Brean wrote: > > There is an I-D for DHCP on IB. IPoIB defines a "broadcast" address and > > DHCP (and ARP) on IB use it. Could make RARP work using this mechanism, > > but as someone else pointed out, the IB hardware address contains a > > QPN. The I-D for IPoIB says something like: > > > > The link-layer address for IPoIB includes the QPN which might not be > > constant across reboots or even across network interface resets. > > Cached QPN entries, such as in static ARP entries or in RARP servers > > will only work if the implementation(s) using these options ensure > > that the QPN associated with an interface is invariant across > > reboots/network resets. > > > > So, there are requirements on the IPoIB implementation to make RARP > > work. Folks in the IPoIB work group decided not to go much further than > > these statements for RARP support since most folks felt that DHCP is (de > > facto) replacement. > > There are 3 cases I can envision: > > 1. A single IPoIB interface per HCA port. In this case, the RARP server > can just match on the hardware address (port GID) without the QPN. > > 2. In the case of VLANs, I think we are likely OK as well. In that case, > there is a separate IP subnet (per PKey) so the port GID is unique per > IP subnet (the port GID is unique on that partition (IP subnet)). I > think there is a different QPN per VLAN. > > So I don't think that the above 2 cases require an invariant QPN. > > 3. The third case is multihomed interfaces on the same IPoIB subnet. I > don't think this is currently supported by IPoIB (but may someday). That > would either not be supported by RARP or some way to have invariant QPNs > would be needed. I'm not sure how important this case is. > > Is the above correct ? Are there other cases ? > > -- Hal >
Some DHCP servers (dhcpd) let you configure a fixed IP per hardware address. It seems to me that making this work requires an invariant QP, right? -- MST - Michael S. Tsirkin _______________________________________________ openib-general mailing list openib-general@openib.org http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
