[ofa-general] Re: [RFC] OpenSM and IPv6 Scalability Proposal

[Eli Dorfman]

On Fri, May 8, 2009 at 4:57 PM, Hal Rosenstock <hal.rosenstock at gmail.com> wrote:
> On Wed, May 6, 2009 at 6:24 AM, Slava Strebkov <slavas at voltaire.com> wrote:
>>
>> In addition to the original proposal we suggest allocating special MLID
>> for the following MGIDs:
>>  1. FF12401bxxxx000000000000FFFFFFFF - All Nodes
>>  2. FF12401bxxxx00000000000000000001 - All hosts
>>  3. FF12401bffff0000000000000000004d  - all Gateways
>>  4. FF12401bxxxx00000000000000000002 - all routers
>>  5. FF12601bABCD000000000001ffxxxxxx - IPv6 SNM
>
> It turns out that collapsing multicast groups across PKeys on a single
> MLID may not be such a good idea unless partition enforcement
> enforcement by switches is disabled. There should be different modes
> of collapsing based on this based on whether this is enabled or not.

The idea is to allocate a different MLID per each of the above special MGIDs.

>> For all other cases we suggest that same MLID will be assigned to
>> different MGIDs if:
>>  1. They share the same P Key
>>  2. Same signature - for IPoIB only
>>  3. Same LSB bits - bitmask configurable by user (default  10 bits)
>>        for example, the following are the same:
>>        MGID1:  FF12401bABCD000000000000xxxxx755
>>        MGID2:  FF12401bABCD000000000000yyyyyB55
>
> Jason's approach to this was in a thread entitled "IPv6 and IPoIB
> scalability issue":
> http://lists.openfabrics.org/pipermail/general/2006-November/029621.html
> in which he proposed an MGID range (MGID/prefix syntax) for collapsing
> IPv6 SNM groups. Additionally, there was the potential to distribute
> the matched groups across some number of MLIDs. See also thread "[RFC]
> OpenSM and IPv6 Scalability Proposal":
> http://lists.openfabrics.org/pipermail/general/2008-June/051226.html
>
>>  Implementation.
>>  Since there will be many mgroups shared same mlid, mlid-array entry
>> will contain
>>  fleximap holding mgroups.
>>  Searching of mgroup will be performed by mlid (index in the array) and
>> mgid -
>>  key in the fleximap.
>
> Sasha proposed using an array rather than fleximap for this:
> http://lists.openfabrics.org/pipermail/general/2008-June/051525.html
>
> -- Hal
>
>>
>>
>>  Slava Strebkov
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