RE: Internet Storage Name Server iSNS Proposal

[Joshua Tseng/Nishan Systems <joshua.tseng@NishanSystems.com>]

Doug,

As you are probably aware, LDAP can be used as the back-end
database access protocol.  There are several reasons why
we think iSNSP would be more favorable to LDAP as the
front-end protocol for storage naming services:

1)  LDAPv3 has a lot of functionality which is not needed for
storage name service.  This could make embedding an LDAP server
on a device such as a switch problematic.  We felt that a simple,
dedicated protocol such as iSNSP would be far easier to embed
on a switch in a similar manner to how name server implementations
are embedded on Fibre Channel switches today.

2)  Similar problem with the name server clients.  If LDAP
was used as the front-end protocol, that would require
every iSCSI device to have an LDAPv3 client implementation,
in order to obtain name service.  I don't believe this would
be a favorable situation, if you think about the extra
CPU-resources required for each target and initiator to
run the LDAP client.  Asynchronous notification must be
implemented, which will consume resources one way or another.

3)  Using iSNSP would allow you to hide the specifics of the
LDAP schema from every name server client.  The LDAP schema
for the back-end database would strictly become implementation-
specific issue.  On the other hand, using LDAP for the front-
end protocol would require a standardized schema that all
clients must understand and conform to.

4)  Using the LDAP persistent search capability for asynchronous
notification requires a TCP connection be kept open for every
client registered to receive the notification.  Again, this
could be problematic for situation 1) above, as the server may
be imbedded on a switch or other resource-constrained device,
and would potentially have to keep 100's of TCP connections open.
The alternative to persistent search is the client update
protocol, which requires every iSCSI device to continually
poll the server for changes.  Also not very scalable.

Josh

> -----Original Message-----
> From: Douglas Otis [mailto:dotis@sanlight.net]
> Sent: Wednesday, October 25, 2000 3:09 PM
> To: Joshua Tseng/Nishan Systems; ips@ece.cmu.edu
> Subject: RE: Internet Storage Name Server iSNS Proposal
> 
> 
> Josh,
> 
> LDAP is an alternative to iSNS.  The FC SNS can publish to 
> LDAP and satisfy
> access requirements.  Information provided by iSNS is not 
> complete with
> provisions of a single IP as example, so it would be interesting to
> understand how an iSNS schema is expanded.
> 
> Include a form-feed at the end of each page to help reviewers.
> 
> For information on secure DNS, investigate 
> http://www.nominum.org.  There
> has been extensive work in this area.
> 
> Doug
> 
> 
> 
> > Folks,
> >
> > Please note that our I-D proposal for a name server for iSCSI is now
> > available:
> >
> > http://search.ietf.org/internet-drafts/draft-tseng-ips-isns-00.txt
> >
> > Please submit comments to me or this list.
> >
> > Thanks!
> >
> > Josh Tseng
> >
>