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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: iSCSI: Portal Group clarification
iSNS Draft data model is not consistent with iSCSI Draft data model. In
iSCSI Data Model a Portal can belong to multiple Portal Groups (though only
once in each iSCSI Node). iSNS Draft data model does not allow this.
Is there any plan to resolve this problem in iSNS Data model? If so when can
we expect a new data model?
iSNS draft data model defines Portal as (Section 4.1.1 page 23 in draft 18)
PORTAL IP Address * * *
TCP/UDP Port * * *
Portal Symbolic Name *
ESI Interval *
ESI Port *
Portal Group Tag *
Portal Index *
SCN Port *
Portal Security Bitmap *
Portal IKE Phase-1 Proposal
Portal IKE Phase-2 Proposal
Portal Certificate
And it clearly says that the key is {IP Address, TCP/UDP Port} pair. This
definition does not allow for registration of Portal which belongs to
multiple Portal Groups (only once in a single iSCSI Node).
Thanks,
Siva
-----Original Message-----
From: Eddy Quicksall [mailto:eddy_quicksall@ivivity.com]
Sent: Friday, April 04, 2003 5:08 AM
To: Kevin Gibbons; ips@ece.cmu.edu
Subject: RE: iSCSI: Portal Group clarification
Thanks,
When I created the diagram, it was just to help me see what the
configurations could be. I then started adding quotes from the spec. Then I
added the titles as a "prompt". The titles are not to describe the objects.
There are several
If you or someone else has some idea as to what title to put over the IP
address, that would be good ... but the spec does not have a definition for
that column.
Eddy
-----Original Message-----
From: Kevin Gibbons [mailto:kgibbons@NishanSystems.com]
Sent: Thursday, April 03, 2003 9:49 PM
To: 'Eddy Quicksall'; KRUEGER,MARJORIE (HP-Roseville,ex1); ips@ece.cmu.edu
Subject: RE: iSCSI: Portal Group clarification
Eddy,
looks good to me, except the IP-Address boxes do not have a title above
them, unlike the "Network Portals", and "Target Portal Groups" above the
other boxes. Perhaps if "Network Portals" was removed above the TCP port
numbers, or the title was moved to the left, or the IP-Address boxes were
also titled, it would be clearer.
Cheers, Kevin
-----Original Message-----
From: Eddy Quicksall [mailto:eddy_quicksall@ivivity.com]
Sent: Thursday, April 03, 2003 5:02 PM
To: KRUEGER,MARJORIE (HP-Roseville,ex1); 'Kevin Gibbons'; ips@ece.cmu.edu
Subject: RE: iSCSI: Portal Group clarification
See what you think of this (if attachments get reflected).
You will notice that I don't draw lines around things like a "Network
Portal" or a "Target Portal Group" because that does not depict what I'm
trying to show ... that information is in the text. For example, "A Network
Portal is identified by its IP address and its listening TCP port" and I
show that by the connecting lines. The same comment applies to a Target
Portal Group.
Johns diagram shows these groupings quite nicely.
Eddy
-----Original Message-----
From: Eddy Quicksall
Sent: Thursday, April 03, 2003 7:42 PM
To: 'KRUEGER,MARJORIE (HP-Roseville,ex1)'; 'Kevin Gibbons'; ips@ece.cmu.edu
Subject: RE: iSCSI: Portal Group clarification
Kevin and Marjorie,
Thanks for pointing that out. When I made the diagram, I didn't really
intend to show an object diagram. I intended to show the flow and connecting
lines between logical parts.
I'll see if I can make a change that will properly depict the Network
Entity.
Eddy
-----Original Message-----
From: KRUEGER,MARJORIE (HP-Roseville,ex1) [mailto:marjorie.krueger@hp.com]
Sent: Thursday, April 03, 2003 6:31 PM
To: 'Kevin Gibbons'; ips@ece.cmu.edu
Subject: RE: iSCSI: Portal Group clarification
The drawing in
http://www.haifa.il.ibm.com/satran/ips/EddyQuicksall-iSCSI-in-diagrams/porta
l_groups.pdf has used the label "network entity" in a manner inconsistent
with the usage/intent in the iSCSI protocol specification. A "network
entity" is meant to represent a computer system with ethernet egress points.
As a computer system, it can contain one iSCSI Node if it's an initiator,
and one or more iSCSI Nodes if it's a target. It's not correct to talk
about an iSCSI Node "accessing" a network entity, it's a containment
relationship.
Portal tags must only be unique within the scope of a single iSCSI target
node, and are 16 bit integers. I don't see where you get the UTF-8 out of
the examples in (1)? I just see numbers, with no mention of what format
they must be exchanged in. Of course, SendTargets commands are character
strings, so the exchange of TargetPortalGroupTags are integers represented
in character format.
Marjorie Krueger
Networked Storage Architecture
Networked Storage Solutions
Hewlett-Packard
-----Original Message-----
From: Kevin Gibbons [mailto:kgibbons@NishanSystems.com]
Sent: Thursday, April 03, 2003 1:17 PM
To: ips@ece.cmu.edu
Cc: 'John Hufferd'; Eddy Quicksall
Subject: RE: iSCSI: Portal Group clarification
I have been reviewing the iSCSI Model examples on
http://www.haifa.il.ibm.com/satran/ips , and am trying to get them straight
in my head. I was hoping someone can help.
Network Entity: Can different entities provide access to the same iSCSI
Node? In 1) "iSCSI Configuration Examples",
http://www.haifa.il.ibm.com/satran/ips/iSCSIConfigurationExamples.pdf, the
iSCSI Network Entity contains iSCSI Nodes and Network Portals. Each Network
Portal has a TCP/IP network address. This limits access to an iSCSI Node to
one Entity, and seems to agree with the architecture model in the iSCSI
draft. But 2) "Portal Groups",
http://www.haifa.il.ibm.com/satran/ips/EddyQuicksall-iSCSI-in-diagrams/porta
l_groups.pdf, shows Network Entities that provide access to, but do not
contain, Network Portals and iSCSI Nodes. These feed into Portal Groups and
then iSCSI Nodes. This would mean multiple Entities can provide access to
the same iSCSI Node, and the example (2) shows this. This seems to disagree
with (1). I tried but could not map this into the iSCSI draft architecture
model.
Portal Tags: Are they uniquely defined using 16 bit integers? In 1) "iSCSI
Configuration Examples" figures, the Portal Tags are specified using UTF-8
characters. But the included Send Targets examples use integer values. In
2) "Portal Groups", integer values are used for defining Portal Tags. This
seems to agree with the iSCSI draft.
Is there a UML/entity-relationship model for the iSCSI architecture? This
would help me a lot. I am aware of one for the iSCSI MIB model, but not the
iSCSI Architecture.
Many Regards, Kevin
-----Original Message-----
From: John Hufferd [mailto:hufferd@us.ibm.com]
Sent: Tuesday, April 01, 2003 11:04 PM
To: Eddy Quicksall
Cc: ips@ece.cmu.edu; Kevin Gibbons; owner-ips@ece.cmu.edu
Subject: RE: iSCSI: Portal Group clarification
Eddy,
Your point is exactly correct!
The key point that was being missed was the words at the bottom of the
figure on page 40 which says "(within Network Entity, not shown)".
When one has more than one target (node) within a Network Entity, the portal
(IP Address:Port) can be part of any of the enclosed Targets. That is
because the path to the Target is defined by the portal (IP Address:Port)
and the Target Name. This is reasonable since nothing is ambiguous about
the description of the path that is intended.
Having said that, there is also NO requirement that all portals need be
connectable to all targets within the Network Entity. This is an
implementation decision. (Just thought I would through that in.)
Your point is also supported by the figure in section 3.4 and also the
following example that describes what is returned by SendTargets for a
Network Entity that has two iSCSI targets:
- iSCSI Draft20 Appendix D : SendTargets Operation
"The next example has two internal iSCSI targets, each accessible via
two different ports with different IP addresses. The following is
the text response:
TargetName=iqn.1993-11.com.example:diskarray.sn.8675309
TargetAddress=10.1.0.45:3000,1
TargetAddress=10.1.1.45:3000,2
TargetName=iqn.1993-11.com.example:diskarray.sn.1234567
TargetAddress=10.1.0.45:3000,1
TargetAddress=10.1.1.45:3000,2 "
.
.
John L. Hufferd
Senior Technical Staff Member (STSM)
IBM/System Group, San Jose CA
Main Office: (408) 256-0403, Tie: 276-0403, eFax: (408) 904-4688
Home Office: (408) 997-6136, Cell: (408) 499-9702
Internet Address: hufferd@us.ibm.com
Eddy Quicksall <eddy_quicksall@ivivity.com>
Sent by: owner-ips@ece.cmu.edu
04/01/2003 05:13 PM
To: Kevin Gibbons <kgibbons@NishanSystems.com>,
ips@ece.cmu.edu
cc:
Subject: RE: iSCSI: Portal Group clarification
Yes.
Note however that a Network Portal can belong to more than one Target Portal
Group but only one Target Portal Group within a single node (which is a
target in this context).
Eddy
-----Original Message-----
From: Kevin Gibbons [mailto:kgibbons@NishanSystems.com]
Sent: Tuesday, April 01, 2003 6:39 PM
To: ips@ece.cmu.edu
Subject: iSCSI: Portal Group clarification
Hi, I would like to make sure I understand the iSCSI model correctly. Can
anyone confirm that a Portal, providing access to a target, is part of
exactly one Portal Group at a time? My reading of the spec indicates this
is true. That each Portal has a 16 bit Portal Group tag. But I would like
to make sure.
I believe that in iSCSI draft 20, it states that a Portal can be part of
exactly one Portal Group. Please see page 15:
- Portal Groups: iSCSI supports multiple connections within the same
session; some implementations will have the ability to combine
connections in a session across multiple Network Portals. A Portal
Group defines a set of Network Portals within an iSCSI Network
Entity that collectively supports the capability of coordinating a
session with connections spanning these portals. Not all Network
Portals within a Portal Group need participate in every session
connected through that Portal Group. One or more Portal Groups may
provide access to an iSCSI Node. Each Network Portal, as utilized by
a given iSCSI Node, belongs to exactly one portal group within that
node.
Also, please see page 39 for similar wording. There is also
a
figure on page 40:
----------------------------IP Network---------------------
| | |
+----|---------------|-----+ +----|---------+
| +---------+ +---------+ | | +---------+ |
| | Network | | Network | | | | Network | |
| | Portal | | Portal | | | | Portal | |
| +--|------+ +---------+ | | +---------+ |
| | | | | | |
| | Portal | | | | Portal |
| | Group 1 | | | | Group 2 |
+--------------------------+ +--------------+
| | |
+--------|---------------|--------------------|--------------------+
| | | | |
| +----------------------------+ +-----------------------------+ |
| | iSCSI Session (Target side)| | iSCSI Session (Target side) | |
| | | | | |
| | (TSIH = 56) | | (TSIH = 48) | |
| +----------------------------+ +-----------------------------+ |
| |
| iSCSI Target Node |
| (within Network Entity, not shown) |
+------------------------------------------------------------------+
Please let me know if I am in error.
Thanks very much! Kevin
-------------------------------------------------
Kevin Gibbons
Nishan Systems, Inc.
kgibbons@NishanSystems.com
(408) 519-3756
-------------------------------------------------
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