[ofa-general] Re: tcp/rdma port unification - iscsi/ddp/toe vs iwarp/ddp/toe

[Steve Wise]

Or Gerlitz wrote:
> Steve Wise wrote:
>   
>> Depends on the 4-tuple. The demux done in the TOE hw uses src addr/port and dst addr/port.  
>>     
>
> Hi Steve, 
>
> Trying to better understand the problem and possible solutions, I looked on the Chelsio iscsi offload driver (drivers/scsi/cxgb3i/* & Documentation/scsi/cxgb3i.txt) - which basically should suffer from the same issue - how to distinguish between a iscsi/os-tcp connection to iscsi/hw-tcp (toe) connection (or to iperf connection, etc as we discussed). 
>
> I saw it manages the source port from its own data-structure (similar to the rdma-cm) but it doesn't  open of a socket / nor bind the port - so I assume that a host opens two iscsi/tcp connections to a target on the same src ip/port - a party starts... At this point I came a cross the "cxgb3: manage private iSCSI IP address" patch whose change log states that its mostly ARP related- is the ARP resolution for iSCSI/DDP/TOE different from iWARP/DDP/TOE? does the below patch/approach eliminates the port space problem for iscsi/ddp?
>
>   


The iscsi offload drivers all maintain their own private ip addresses 
hidden from the native stack.  That's how they keep the 4-tuple unique.


Steve.