[openib-general] RDMA Generic Connection Management

[Yaron Haviv]

> -----Original Message-----
> From: Talpey, Thomas [mailto:Thomas.Talpey at netapp.com]
> Sent: Tuesday, August 30, 2005 12:54 PM
> To: Yaron Haviv
> Cc: openib-general at openib.org
> Subject: RE: [openib-general] RDMA Generic Connection Management
> 
> At 10:55 AM 8/30/2005, Yaron Haviv wrote:
> >The iSCSI discovery may return multiple src & dst IP addresses and
the
> >iSCSI multipath implementation will open multiple connections.
> >There are many TCP/IP protocols that do that at the upper layers
(e.g.
> >GridFTP, ..), not sure how NFS does it.
> 
> 
> To answer the question of how NFS "finds out" about multiple
> connections and trunking, the answer is generally that the mount
> command tells it. Mount can get this information from the command
> line, or DNS. I believe Solaris uses the command line approach. There
> may be a way to use the RPC portmapper for it, but the portmapper
> isn't used by NFSv4.
> 
> Bottom line? NFS would love to have a way to learn multipathing
> topology. But it needs to follow existing practice, such as having
> an IP address / DNS expression. If the only way to find it is to query
> fabric services, that's not very compelling.
> 
> Tom.

Tom, from your description it looks like the multipathing is done based
on IP addressing (like iSCSI/iSER, GridFTP, ..) and resolved by the ULP
or its name service, in that case the ULP probably opens few connections
from one or more IPs to one or more other IPs.

This mean that we don't need a transport dependent mechanism as long as
each port is associate with a unique IP (like we do today in OpenIB).
(Another good reason to use IP addressing)

Yaron