On Thu, 2006-09-14 at 00:46, Michael S. Tsirkin wrote: > Quoting r. Hal Rosenstock <[EMAIL PROTECTED]>: > > Subject: Re: [PATCH] IB/ipoib: use appropriate path selector > > > > On Wed, 2006-09-13 at 18:08, Michael S. Tsirkin wrote: > > > Quoting r. Roland Dreier <[EMAIL PROTECTED]>: > > > > Subject: Re: [PATCH] IB/ipoib: use appropriate path selector > > > > > > > > Michael> IPoIB in linux needs 2K MTU. Therefore it must set mtu > > > > Michael> selector in path record query accordingly. > > > > > > > > Umm -- why does it need a 2K MTU? As far as I know it should work > > > > fine with any MTU, assuming the SA sets the MTU of the broadcast > > > > multicast group correctly. > > > > > > Hmm, you are right, it is just that existing implementations all > > > set that to 2K. > > > > By default yes. It can be configured. > > > > > But there is a silent assumption that MTU of any path is >= broadcast > > > multicast group MTU, and this is what I want to fix. > > > > The spec says: > > "The value (for IB MTU) assigned to the broadcast-GID must not be > > greater than any physical link MTU spanned by the IPoIB subnet". > > so if the broadcast group is improperly setup not to follow this, there > > will be other issues. > > Correct. IPoIB uses broadcast group MTU to get the value reported to > Linux. If some link has a lower MTU IPoIB can not use it. > > > It doesn't need to be included in the PR request. > > I disagree here. If you do not set selector, SA is free to return > a path with lower MTU even though physical link allows higher MTU. > Does it say otherwise somewhere?
No but isn't this relying on using PRs in a certain way by IPoIB implementations (and any other UD application) v. connected apps ? -- Hal _______________________________________________ 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
