[openib-general] Re: Re: Re: [PATCH] change Mellanox SDP workaround toa moduleparameter

[Hal Rosenstock]

On Sun, 2006-02-19 at 08:12, Michael S. Tsirkin wrote:

> > > The SWG defined a generic mechanism which uses REJ to indicate that the
> > > passive side does not accept a certain REQ fields, and allows the passive
> > > side to indicate an alternative value. Indirection is also supported through
> > > the same protocol. It also allows the active side, following the REJ, to use
> > > an alternate value, other than the one suggested by the passive side, i.e.
> > > passive side only has a veto capability. This is the mechanism and the short
> > > theory behind it. Unfortunately it's a bit inefficient in terms of
> > > performance because of the ping pong of messages. Solving just the MTU might
> > > not be a good enough argument. The approach should be to enable the active
> > > side to specify a set of acceptable parameters for each one of the REQ
> > > fields, and then let the passive side to choose. This may change the CM
> > > packets all over and will introduce new problems. I don't think that there's
> > > a good chance of just adding a solution for just one of the fields. Anyway,
> > > you can still try and propose this to IBTA, I tried it once already :)
> > 
> > Thanks for the historical perspective. It's harder to overturn an
> > existing vote on something at the IBTA. Not sure I have the time to take
> > up this (larger) mission.
> 
> Assuming the spec says as it is, then:
> 1. CMA needs to be modified to retry the connection if its rejected because
>    of lower MTU.
> 2. SDP/SRP protocols specs need a clarification: e.g. current SDP spec
>    says the connection should be closed when we get a REJ.

Can you be specific about the spec citations for SDP and SRP for REJ
handling ? Isn't it more the retry strategy once the connection is
REJected ? Is that in those specs ?

-- Hal