RE: SCSI URL scheme [WAS: Re: iSCSI: 2.2.6. Naming & mapping]

["Douglas Otis" <dotis@sanlight.net>]

Milan,

> I'd like to chime in with my agreement, worded a bit differently:
>
> 1) I believe large systems (spanning the Internet) will at some point
>    need some form of proxy/gateway/NAT because:
>     - addresses in one realm won't be legal in another realm
>     - the owner of a realm does not want any of its internals revealed
>     - those internals are changeable, and the owner wants to isolate
>        outsiders from the impact of those changes.

In suggesting a desire to allow dynamic routing, you are insisting on
designing a new type of name server.  At some point, even the names would
need to be shared with the client.  To maintain these names and internal
addresses, LDAP provides this services.  LDAP would allow isolation and
control in both the realm of the client and the provider.

> 2) Authentication, privacy (a.k.a. encryption), etc are indeed a separate
>    issue from end-point naming.

Yes, but you would need to resolve the name before checking the
authentication.  You have made the process of checking and routing more
difficult.  It is also unlikely that the address space will look anything
like an IP address.  It is also likely some vendors may require additional
parameters shared between the client and provider.  LDAP allows for such
sharing.

> 2a) Information obtained by observing and parsing an embedded identifier
>    should have no impact on overall security - We aren't relying on
>    "security by obscurity," after all.

You are making security weaker by any measure.  Why insist on adding a
parser to SCSI transport?  Let LDAP do the parsing and providing the
directory structures.  Why re-invent this?

> 2b) ditto, whether those identifiers are human-readable or not.
>
>
> 3) Let's assume that the available tools and techniques of DNS, URLs,
>    etc are there to be leveraged, and let's see where it takes us.
>    I'd rather spend our time delivering a robust application,
>    rather than inventing optimized replacements for common
>    Internet tools.

In my knowledge, there is no SCSI name server.  Although there are
pre-existing concepts of DNS and URLs, these do not apply to SCSI, they
apply to IP.  This is not IP, this is SCSI.  If you wish leverage, use LDAP.
Otherwise, you will spend your time parsing script, managing databases, and
making access tools for sharing this information between clients and
providers.

Doug

>
> - Milan Merhar
>
>
>
> -----Original Message-----
> From: Joshua Tseng [mailto:jtseng@NishanSystems.com]
> Sent: Tuesday, October 03, 2000 2:43 PM
> To: Douglas Otis; ips@ece.cmu.edu
> Subject: RE: SCSI URL scheme [WAS: Re: iSCSI: 2.2.6. Naming & mapping]
>
>
> Doug,
>
> I'm not sure we understand each other anymore.  I will just carefully
> restate my points, and leave it at that.
>
> 1)  URL's (domain name & path) are needed in the iSCSI transport to
> support proxy services.  Because of the prevalence of NAT, proxies
> are necessary.
>
> 2)  Authentication is a separate issue and has nothing to do with
> identifying the final destination device/LUN/WWN of the iSCSI traffic.
> A separate key distribution server may improve scalability of the
> authentication mechanism, but this has nothing to do with addressing
> and routing of iSCSI traffic.
>
> 3)  A LANE-type architecture for addressing and routing of iSCSI
> traffic is a bad idea due to scalability and management issues.
> The iSCSI transport must have imbedded routing information in the
> form of a URL, to allow proxies and destination nodes to route
> iSCSI traffic to its final device/LUN/WWN destination.
>
> Best regards,
> Josh Tseng
>
> -----Original Message-----
> From: Douglas Otis [mailto:dotis@sanlight.net]
> Sent: Tuesday, October 03, 2000 11:13 AM
> To: Joshua Tseng; ips@ece.cmu.edu
> Subject: RE: SCSI URL scheme [WAS: Re: iSCSI: 2.2.6. Naming & mapping]
>
>
> Joshua,
> <snip>
>
> > What you describe might be possible (although I still think it's a bad
> > idea) if the entire Internet, including all public and private networks,
> > were in a single consolidated address space.  But the fact is we are
> > running out of address space, and there is something called NAT defined
> > in RFC1918.  Who knows, with IPv6, this may change, or it might
> not.  But
> > it is a reality today.  To operate in an environment with NAT, you need
> > proxies.  There's no way around it.  A client in a public network using
> > registered IP address space should NEVER see a 10.0/8 address.
> It should
> > NEVER talk to a 10.0/8 address, and it shouldn't even have a 10.0/8
> > address entry in its routing table.  It must first talk to a dual-homed
> > proxy with at least one leg using registered IP address space, in order
> > to communicate with a host with a 10.0/8 address.  In this environment
> > and with these restrictions, I don't understand how you can remove the
> > involvement of the proxy in the process of what you call
> "authentication".
> >
> > BTW, it's not just http--e-mail and many other applications today make
> > extensive use of proxy relays as well.
> >
> > Josh
>
> Yes, and most enterprise environments include a NAT.  Even homes with DSL
> include NAT.  A few may even use a proxy.  That does not mean private
> addresses of the target can not be shared at the time of
> authentication.  I
> would have expected such an exchange.  As most of these things work, such
> permission is in the form of a lease.  I would also expect as the map is
> declared, mapping screens are established based on the permission
> discovered
> at the time of authentication.  Before and not during use.  Using a binary
> address does not mean PUBLIC addresses.  It may not even be IP.
> It could be
> SCSI address or perhaps an encoded address.  You do not want SCSI to look
> like an HTTP server.  Especially if you wish this application to
> scale, you
> do not want to be doing in-band name lookup and authentication.
>
> Pleases, this is not a web server, it is a portal to SCSI
> devices.  A client
> does not need to use a name to get a proxy to listen, try just
> typing the IP
> of a web site.  The proxy will forgo the lookup.  Name lookup is simply a
> convenience for humans.  You would not want to depend on a round-robin
> selection of IPs from DNS should there be more than one such IP.
> How would
> you select the alternative IP, the next in the list?  All these parameters
> can be concisely defined in the authentication exchange.  I can
> not see why
> someone would wish to place a name on their SCSI portal but they
> could.  The
> only name that needs to exist is the authentication server.  I would not
> expect an address beyond the SCSI portal to be PUBLIC IPs.  I would not
> expect them to be IP.  LDAP is good at doing symbolic lookup.
> Let it do the
> work at the time of authentication.  Don't invent a SCSI browser.
>
> Doug
>