Return-Path: X-Sieve: cmu-sieve 2.0 Return-Path: Received: (from majordom@localhost) by ece.cmu.edu (8.11.0/8.10.2) id h33MMAg01362 for ips-outgoing; Thu, 3 Apr 2003 17:22:10 -0500 (EST) X-Authentication-Warning: ece.cmu.edu: majordom set sender to owner-ips@ece.cmu.edu using -f Received: from mail.ivivity.com ([64.238.111.99]) by ece.cmu.edu (8.11.0/8.10.2) with ESMTP id h33MM6301353 for ; Thu, 3 Apr 2003 17:22:06 -0500 (EST) Received: by ATLOPS with Internet Mail Service (5.5.2653.19) id <2CY0SCG6>; Thu, 3 Apr 2003 17:22:05 -0500 Message-ID: From: Eddy Quicksall To: Kevin Gibbons Cc: "'John Hufferd'" , ips@ece.cmu.edu Subject: RE: iSCSI: Portal Group clarification Date: Thu, 3 Apr 2003 17:22:04 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C2FA2F.747F4560" Sender: owner-ips@ece.cmu.edu Precedence: bulk This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01C2FA2F.747F4560 Content-Type: text/plain I commented to the 1st part but I don't understand the 2nd part. I didn't specify the "type" of integer in the Portal Tags. Please clear this up. Eddy -----Original Message----- From: Kevin Gibbons [mailto:kgibbons@NishanSystems.com] Sent: Thursday, April 03, 2003 4:17 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 Sent by: owner-ips@ece.cmu.edu 04/01/2003 05:13 PM To: Kevin Gibbons , 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 ------------------------------------------------- ------_=_NextPart_001_01C2FA2F.747F4560 Content-Type: text/html Content-Transfer-Encoding: quoted-printable Message

I commented to the 1st = part but I don't understand the 2nd part. I didn't specify the "type" of integer in the Portal Tags. Please clear this = up.

 

=

Eddy

 

=

-----Original = Message-----
From: Kevin Gibbons [mailto:kgibbons@NishanSystems.com]
Sent: Thursday, April = 03, 2003 4:17 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/iSCSIC= onfigurationExamples.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/EddyQu= icksall-iSCSI-in-diagrams/portal_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=3Diqn.1993-11.com.example:diskarray.sn.8675309
        TargetAddress=3D10.1.0.45:3000,1
        TargetAddress=3D10.1.1.45:3000,2
        TargetName=3Diqn.1993-11.com.example:diskarray.sn.1234567
        TargetAddress=3D10.1.0.45:3000,1
        TargetAddress=3D10.1.1.45:3000,2   = "
       

.
.
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 =3D 56)     =      |  |       (TSIH =3D 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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