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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: iSCSI: Portal Group clarificationSiva, The iSCSI Architecture model, draft 20, has one Portal Group Tag assigned per Portal, with the Portal to Portal Tag mapping unique for each Storage Node within an Entity. Therefore, each Portal has one valid Portal Group Tag value per Storage Node in an Entity. The iSNS model is an Entity object containment model, where each Storage Node has access to each Portal in an Entity. With this model, the Portal to Portal Tag mapping is unique within an Entity. Therefore, each Portal has one valid Portal Group Tag value in an Entity. I have been working on an update to the iSNS model that allows a Portal Group Tag mapping to exist per iSCSI Storage Node. I first wanted to make sure I understood the iSCSI Architecture model. I have been reviewing examples/literature and comparing them to draft 20, as well as discussing options with the iSNS co-authors. The intent is to make a small change to the iSNS model, keeping the existing iSNS attributes, yet support all possible iSCSI Portal Group Tag assignments. I hope to have an update to the iSNS draft ready for WG review shortly. Thanks, Kevin -----Original Message----- From: Siva Vaddepuri [mailto:Siva.Vaddepuri@MCDATA.com] Sent: Friday, April 18, 2003 11:02 AM To: 'Eddy Quicksall'; Kevin Gibbons; ips@ece.cmu.edu Subject: 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! 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