[openib-general] SA cache design

[Hal Rosenstock]

On Thu, 2006-01-05 at 17:04, Sean Hefty wrote:
> >> I hadn't fully figured this out yet.  I'm not sure if another MAD class is
> >> needed or not.  My goal is to implement this as transparent to the
> >application
> >> as possible without violating the spec, perhaps appearing as an SA on a
> >> different LID.
> >
> >The LID for the (real) SA is determined from PortInfo:MasterSMLID so I
> >don't see how this could be done that way.
> 
> I didn't think that it was a requirement that the SA share the same LID as the
> SM.

For the precise language, see C15-0-1.24 p. 923 IBA 1.2:


C15-0.1.24: It shall be possible to determine the location of SA from
any
endport by sending a GMP to QP1 (the GSI) of the node identified by the
endport's PortInfo:MasterSMLID, using in the GMP the base LID of the
endport as the SLID, the endport's PortInfo:MasterSMSL as the SL, the
well-known Q_Key (0x8001_0000), and whichever of the default P_Keys
(0xFFFF or 0x7FFF) was placed in the endport's P_Key Table by the SM
(Table 183 Initialization on page 868).

so I overstated it a bit but this needs to be obeyed.

Also,

C15-0.1.25: A SubnAdmGet(ClassPortInfo) sent according to C15-
0.1.24: shall return all information needed to communicate with Subnet
Administration. Alternatively, valid GMPs for SA sent according to C15-
0.1.24: shall either return redirection responses providing all such
information, or shall be normally processed by SA.

-- Hal