Comments on 03-183r4 Management Address VPD page

Charles Binford Charles.Binford at sun.com
Tue Oct 14 13:20:10 PDT 2003


* From the T10 Reflector (t10 at t10.org), posted by:
* Charles Binford <Charles.Binford at Sun.COM>
*
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George, thanks for the comments on T10/03-183r4.
 
I'm not opposed to a Report Network Address well known LU (WKLU) but I
don't see the need for it.  I believe the proposal as it stands is very
straightforward to implement and has a lot of flexibility to different
vendors to fit it to their needs. 
 
- each LU in the system either has page x85 info or it doesn't.  If it
does, it  throws x85 in the list of supported pages (x00).  
 
- I would assume a very common implementation would be that each LU
doesn't know the management address, but it has an API to get the info.
This type of data isn't LU specific (which is why I assume your pushing
to usage of WKLU), but I don't think it is any big deal for any LU in
the system to call an internal API to retrieve the info.
 
- moving to the use of WKLU undoes the usefulness having the ASSOCIATION
field in the descriptor.  I can imagine cases where a management address
is specific to the entire target device, and other cases where the
management address is specific to a particular port or LU.
 
Charles Binford 
Sun Microsystems 
316.315.0382 x222 



I have a basic problem with this because you provide no information
about what logical unit is supposed to know about the information
returned in this VPD. From the way it is currently written it appears
that any and/or all logical units would be able to return this
information. That implies that all logical unit would know not just
about the network address but also the service type associated with the
network address. To take this one step further; in a SCSI target that
contains 100s of virtual logical units it would appear that all of them
would somehow have to know about all this. I see this as a major
problem. To resolve this I suggest you make the following changes:. 

a) Change the first paragraph of 7.5.6 in our proposal to: 

This VPD page (see table x) provides a list of network addresses of
management services contained within a SCSI target device. Application
clients should use the REPORT NETWORK  ADDRESS well known logical unit
to retrieve a complete list of network addresses and their service
types. 

b) Add the following into your proposal: 

8.x REPORT NETWORK  ADDRESS well known logical unit 

The REPORT NETWORK  ADDRESS well known logical unit shall only process
the commands listed in table 298. If a command is received by the REPORT
NETWORK  ADDRESS  well know logical unit that is not listed in table xxx
the device server shall return CHECK CONDITION status with the sense key
set to ILLEGAL REQUEST and an additional sense code of INVALID COMMAND
OPERATION CODE. 

The REPORT NETWORK  ADDRESS well known logical units shall support the
INQUIRY command's Management Network Addresses VPD page. The returned
Management Network Addresses VPD page shall contain all the network
addresses of management services associated with a SCSI target device
that contains the REPORT NETWORK ADDRESS well known logical unit. If any
other well known logical units within a SCSI target device returns the
Management Network Addresses VPD page they shall return the same list of
network addresses. 

Table xxx would contain: Inquire, Request Sense, and TUR. 

Bye for now,
George Penokie

Dept 2C6  114-2 N212
E-Mail:    gop at us.ibm.com
Internal:  553-5208
External: 507-253-5208   FAX: 507-253-2880



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 Message  
 George, thanks for the comments on T10/03-183r4.
  
 I'm not opposed to a Report Network Address well known LU (WKLU) but I don't see the need for it.  I believe the proposal as it stands is very straightforward to implement and has a lot of flexibility to different vendors to fit it to their needs. 
  
 - each LU in the system either has page x85 info or it doesn't.  If it does, it  throws x85 in the list of supported pages (x00).  
 
 - I would assume a very common implementation would be that each LU doesn't know the management address, but it has an API to get the info.  This type of data isn't LU specific (which is why I assume your pushing to usage of WKLU), but I don't think it is any big deal for any LU in the system to call an internal API to retrieve the info.
  
 - moving to the use of WKLU undoes the usefulness having the ASSOCIATION field in the descriptor.  I can imagine cases where a management address is specific to the entire target device, and other cases where the management address is specific to a particular port or LU.
  
 Charles Binford 
Sun Microsystems 
316.315.0382 x222 


I have a basic problem with this because you provide no information about what logical unit is supposed to know about the information returned in this VPD. From the way it is currently written it appears that any and/or all logical units would be able to return this information. That implies that all logical unit would know not just about the network address but also the service type associated with the network address. To take this one step further; in a SCSI target that contains 100s of virtual logical units it would appear that all of them would somehow have to know about all this. I see this as a major problem. To resolve this I suggest you make the following changes:. 

a) Change the first paragraph of 7.5.6 in our proposal to: 

This VPD page (see table x) provides a list of network addresses of management services contained within a SCSI target device. Application clients should use the REPORT NETWORK  ADDRESS well known logical unit to retrieve a complete list of network addresses and their service types. 

b) Add the following into your proposal: 

8.x REPORT NETWORK  ADDRESS well known logical unit 

The REPORT NETWORK  ADDRESS well known logical unit shall only process the commands listed in table 298. If a command is received by the REPORT NETWORK  ADDRESS  well know logical unit that is not listed in table xxx the device server shall return CHECK CONDITION status with the sense key set to ILLEGAL REQUEST and an additional sense code of INVALID COMMAND OPERATION CODE. 

The REPORT NETWORK  ADDRESS well known logical units shall support the INQUIRY command's Management Network Addresses VPD page. The returned Management Network Addresses VPD page shall contain all the network addresses of management services associated with a SCSI target device that contains the REPORT NETWORK ADDRESS well known logical unit. If any other well known logical units within a SCSI target device returns the Management Network Addresses VPD page they shall return the same list of network addresses. 

Table xxx would contain: Inquire, Request Sense, and TUR. 

Bye for now,
George Penokie

Dept 2C6  114-2 N212
E-Mail:    gop at us.ibm.com
Internal:  553-5208
External: 507-253-5208   FAX: 507-253-2880



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