Subject: iSCSI: rev07 - ISID-TSID & naming comments

From: "Mallikarjun C." <[email-masked]>
Date: Tue, 14 Aug 2001 12:23:22 -0700

Julian,

Some comments in this area.

- Section 2.10.6, last sentence in para 1 states "An initiator is
uniquely
  identified by the value pair (InitiatorName, ISID).".  Suggest s/b
"initiator"
  with "initiator SCSI port".

- Section 2.11.4, first sentence.  "The TSID is an initiator identifying
tag 
  set by the target." s/b with "The TSID is a target-defined tag
assigned to 
  an initiator SCSI port.".

- Section 1.5, para 1, "Network portals (IP names, addresses and TCP
ports)"
  Suggest dropping "IP names" since what really matters is just the IP
addresses
  and TCP ports.  IIRC, two DNS names can resolve to the same IP
address, and one 
  DNS name can resolve to multiple IP addresses.

- The section in general is not consistent in the usage of iSCSI Name. 
It uses 
  "iSCSI name" "iSCSI Node name", and "iSCSI Name".  I would suggest
using 
  a consistent phrase wherever iSCSI-defined Names are used, like
"iSCSI-Name".  
  Simlar comments  apply for "Network Portal".

- Section 1.5.1, description for "Network Entity" has "This device or
gateway 
  may support one or more iSCSI Node" s/b with "This device or gateway
may
  support one or more iSCSI Nodes and one or more Network Portals". 
Similarly
  for "The iSCSI Node is accessed via a network portal", s/b with "The
iSCSI 
  Node is accessed via one or more network portals".

- Section 1.5.1, description for "iSCSI Node".  The reasoning offered
for the
  definition for iSCSI-Names is not quite right.  Suggested sentence
"iSCSI-Names
  are required because multiple iSCSI Nodes may be present behind a
given 
  combination of IP address and TCP port.".

- Section 1.5.1, second para under "iSCSI Node" discussion, first
sentence.  This
  states that names are not required for default node access.  Is this
still true?  I 
  thought we are  mandating InitiatorName and TargetName text key
exchange now.

- Section 1.5.1, description for "Network Portal".  Suggest rewording
the very first 
  sentence to include the  last sentence.  The current first sentence 
appears very
  vague ("port" - TCP/SCSI/ethernet?).  Also the last sentence defines a
network 
  portal for a target to comprise the "listening TCP port", should we
identify what
  it is for an initiator?  

- The picture shown at the beginning of section 1.5 does not show TCP
port
  being part of the Network Portal on the initiator side.  Is it then
implied that 
  only the IP address constitues a Network Portal for an initiator iSCSI
Node?
   
- Section 1.5.2, last para.  This defines the I-T nexus as the session
for iSCSI.
  This doesn't suggest a nexus identifier - is it the four tuple
<InitiatorName, 
  ISID, TargetName, portal group tag> or the SSID <ISID, TSID>?  Or is
it both 
  - the four-tuple being nexus id at the SCSI layer, and the latter at
the iSCSI
  layer?

- Section 1.5.3, second para with the ISID RULE, last sentence.  Suggest
"...nor 
  does it preclude other sessions with different ...." s/b with "...nor
does it
  preclude multiple sessions with different....".

- Section 1.5.3, third para.  This mentions the term "parallel nexus". 
I assume 
  the equivalence of two 4-tuples is what is being implied here.  Unless
this term 
  is already defined in some latest SCSI documents, I suggest defining
this as 
  such.

- Section 1.5.2 does not comment on if iSCSI mandates the support of
SCSI Port names
  for iSCSI initiators (the requirement appears only the iSCSI targets
para).  
  I assume it is mandatory. 

- The following initiator requirement:
"The iSCSI Name should be configurable parameter of each initiator
portal group."
   would be more clear if stated as (if this is a correct
interpretation):
"All the initiator portal groups of one iSCSI Node MUST share the same 
 iSCSI-Node name."

   Similar comments apply for the target requirement.
- The following initiator requirement:
"The ISID name space of the iSCSI Initiator should be partitioned among
the initiator
 portal groups."
   would be better stated as (if this is a correct interpretation):
"All initiator portal groups of one iSCSI Node MUST share an ISID name
space 
 for sessions established to one iSCSI target node.  Sessions
established to 
 multiple iSCSI target nodes MAY share one ISID name space."

- The following target requirement:
"The TSID name space of the iSCSI Target should be partitioned among the
target 
portal groups."
   would be better stated as (if this is a correct interpretation):
"All target portal groups of one iSCSI Node MUST share an TSID name
space for 
sessions established to one iSCSI initiator node.  Sessions established
to 
multiple iSCSI initiator nodes MAY share one TSID name space."

-- 
Mallikarjun 

Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions Organization
MS 5668 Hewlett-Packard, Roseville.
[email-masked]