Subject: Re: [Ipoverib] IPoIB architecture/encapsulation

From: "Vivek Kashyap" <[email-masked]>
Date: Tue, 11 Dec 2001 10:14:53 -0800

OK. That settles it then.

LID is always chosen by the SM.  Therefore  IP address to the MLID  mapping
or MGID to MLID mappings are beyond the control of IPoIB and hence beyond
its scope.

BTW:  Wouldn't it be possible to set the value MLID in the MCGroupRecord
create request  ? That would be an interface since the same method is
suggested for specifying the P_Key in the create request.

Vivek
--
Vivek Kashyap
[email-masked]
[email-masked]
Ph: 503 578 3422 T/L: 775 3422

                    Vandana Rao                                                                                   
                    <[email-masked]       To:     Vivek Kashyap/Beaverton/IBM@IBMUS, [email-masked]         
                    p.com>               cc:     [email-masked]                                                
                                         Subject:     Re: [Ipoverib] IPoIB architecture/encapsulation             
                    12/11/2001                                                                                    
                    08:31 AM                                                                                      

At 11:59 PM 12/10/2001 -0800, Vivek Kashyap wrote:
<snip>

>Section 3.4 Multicast address to LID mapping, IMO not much of
>explanation is needed here because according to IB spec., LID is
>allocated and managed by SM, period. (Clients can't specify a MLID when
>creating a MCGroupRecord.)
>
><VK>
>Yes, they can. See section 3.5.11.2.1.
>
>  " 1) An (administrative) application defines (or determines) a target
>multi-cast
>    group address (GID). It specifies particular group characteristics
>    (PMTU, raw, P-Key, etc.) and creates the multicast group by invoking
>    a multicast group create to the multicast management entity. This
>ap-plication
>    may request a specific multicast LID or have one allocated
>    for it. "

Section 3.5.11.2 is incorrect and an erratum against this has already been
filed by the IB MgtWG as it
is inconsistent with what is stated in the SA chapter (which is where the
the compliance statements regarding multicast group create are defined).
The MLID is always created by the SM/SA. The application has no interface
available to specify MLIDs.

-Vandana

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---

From: "Bill Swortwood" <[email-masked]>
Date: Tue, 11 Dec 2001 11:09:58 -0800

Vivek -

 The compliance statement on 724-725 (Vol 1.a) is a bit confusing, to be
sure. But the
intent was to allow specification of the Q_Key, MTU and PKey for a multicast
group, with some allowance to set the MGID. The MLID usage in the attribute
is for later query or deletion, but not to set. See specification text
below:

A multicast group can be created by the SubnAdmSet() method, specifying
Add Record in the edit modifier, the Q_Key, MTU and the P_Key (all
other fields are zero). If a particular MGID is required, it can be
specified
in the SubnAdmSet() as well. When a multicast group is deleted, it can be
done by the SubnAdmSet() method, specifying the Delete Record in the
edit modifier and the McGroupRID. Alternatively, it can specify the MGID,
Q_Key, MLID, MTU and P_Key. If a field is and can be set to zero for a
delete, it will result in a match for that field for all MCGroupRecords by
Subnet administration.

Vandana is correct, and has just earned her black belt in MGTWG spec
folklore. :)

- Bill

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf
Of Vivek Kashyap
Sent: Tuesday, December 11, 2001 10:15 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]
Subject: Re: [Ipoverib] IPoIB architecture/encapsulation

Vivek

                    Vandana Rao
                    <[email-masked]       To:     Vivek
Kashyap/Beaverton/IBM@IBMUS, [email-masked]
                    p.com>               cc:     [email-masked]
                                         Subject:     Re: [Ipoverib] IPoIB
architecture/encapsulation
                    12/11/2001
                    08:31 AM

-Vandana