RE: iFCP fabric attachments

[Charles Monia <cmonia@NishanSystems.com>]

Hi Venkat:

See  responses below.

> -----Original Message-----
> From: Venkat Rangan [mailto:venkat@rhapsodynetworks.com]
> Sent: Wednesday, December 13, 2000 6:01 PM
> To: Robert B. Harmon; cmonia@NishanSystems.com; ips@ece.cmu.edu
> Subject: RE: iFCP fabric attachments
> 
> 
> Robert,
> 
> I think when we combine the FCIP proposal and iFCP proposal, 
> you would get
> what you are asking for. That would provide connectivity 
> between FC switches
> using the FC B_Port functionality and IP FCP Portal connectivity. The
> integrated proposal needs to work on things such as Principal Switch
> selection, DomainId distribution among the FC switch across 
> islands etc.
> This is a combination of Fabric Controller and Name Server 
> functionality of
> FC-SW-2 and FC-GS-3 proposals. One thing I am curious about 
> is the FC Name
> Server Object's IP address field, carrying the mapping of DAP 
> to IP address.

> 
> One other area that is needs attention is support for FC 
> Arbitrated Loops -
> they exist in significant numbers, especially at the target side.
> 

From a storage protocol perspective, N_PORT and NL_PORT behaviors are
identical. For that reason, arbitrated loop support in iFCP is a gateway
implementation issue.  Ie.  In a loop implementation, an iFCP gateway would
simply present such devices on the network as individual N_PORTs.

> -----Original Message-----
> From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
> Robert B. Harmon
> Sent: Wednesday, December 13, 2000 10:46 AM
> To: cmonia@NishanSystems.com; ips@ece.cmu.edu
> Subject: iFCP fabric attachments
> 
> 
> I think this is a very interesting proposal, storage gateways are
> possible
> at several different levels, great work.
> 
>  Section 3.3 says:
>     The gateway builds the store of N_PORT network addresses for
>     external devices in the IP fabric by:
> 
>     a) Intercepting name service requests issued by directly-attached
>        N_PORTs and redirecting them to the iSNS name server or,
> 
>     b) Intercepting incoming N_PORT login requests from external Fibre
>        Channel devices.
> 
> Could you explain how this would work in the presence of existing
> Fibre Channel SNS and master switch?
> 
> I noticed on your comparison of FCIP and iFCP that the SAN islands
> contain no Switches or Hubs, N_PORTS are connected directly to iFCP
> devices. Is is possible under to have iFCP gateways and FC switches?
> 

Absolutely, yes.

Once again, this becomes a gateway implementation option. In this case, all
FC switch traffic would be handled internally by the gateway.  In this case,
the only visible FC entities on the IP side of the gateway are the N_PORT
storage devices themselves.  The other stuff is opaque.

It appears that the iFCP spec should probably discuss such implementation
issues.


Charles