Re: iSCSI: NIC interoperability

["Julian Satran" <Julian_Satran@il.ibm.com>]

Mallikarjun,

I have repeatedly stated that from a practical point of view we are
spending a lot of ink on a non-issue.
I have even insisted on mandating C in the draft. Some of the list
members/readers/authors seem to consider such a requirement as "excessive"
- as it implies resorting to a higher authority on every session creation -
and that might not be strictly necessary (although it will be sufficient).
Adding a text key is neither simpler nor easier nor will it solve the
conflict problem.
And I have very little time and patience left for pages of debate on the
merits of one or other port naming script.

Julo



                                                                                              
                    "Mallikarjun                                                              
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                    <cbm@rose.hp.c       cc:                                                  
                    om>                  Subject:     iSCSI: NIC interoperability             
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                    10-10-01 04:14                                                            
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After seeing some of the emails on this topic from Dave
Sheehy, David Black and Jim Hafner, I have some comments
and questions.

It appears to me that the following three are the major
issues that one has to deal with for building a multi-NIC
iSCSI Node, where the NICs are potentially from different
vendors.
           A. Each NIC MUST allow the Node name to be configurable.
           B. Each NIC MUST allow the ISID range to be configurable
           (if deployed in an initiator configuration).
           C. In addition, if only one (initiator/target) portal group
           is sought to be presented (i.e. session spanning across
           any and all of these NICs is a requirement), each NIC
           MUST allow itself to be managed by an externally-resident
           "session manager" in some "TBD standard way".

Admittedly, C is is the hardest and till the "TBD standard way"
is defined to interact with a session manager, it cannot be
mandated.  Failure to comply with C would only create multiple
portal groups in an iSCSI implementation - each portal group
limited to NIC(s) from a given vendor.

But, A and B above seem reasonable and in fact seem required
to be mandated - both to avoid the problems as with FC Node
Name, and also to address the concerns of not leaving target
with a deterministic way to enforce access control mechanisms
and such.

I realize that the "no duplicate nexus" goal does not strictly
require A (hence neither B), but I recommend that A be mandated,
thus automatically making B an additional requirement for initiator
configurations.  Rev08 iSCSI draft seems to refer to A and B
in section 9 (implementation notes) as "should".  Was there a
concern about the appropriateness of mandating A and B in the
main modeling discussion?  They appear fairly straightforward
to implement.

If the reasoning was not to require _any_ configuration of an
iSCSI NIC, I would argue that you require some "name" to be
configurable anytime you want to build a logically monolithic
entity (as in a node) from smaller components (each of which
can act as a logically independent entity in its own right).

Comments from NDT and/or Julian would help.

Thanks.
--
Mallikarjun

Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions Organization
MS 5668 Hewlett-Packard, Roseville.
cbm@rose.hp.com