RE: summary of iSCSI meeting 22 June 2000

[JoeBre@exabyte.com]

Title: RE: summary of iSCSI meeting 22 June 2000

Comments inline

> ...
>
> Further discussion of what happens when TCP packets get lost,
> especially if
>  they contain an iSCSI header.
> How well can iSCSI compete with FC if we are so dependent on
> TCP, with its
> dropped packets.

All error handling for dropped packets should exist below the SCSI layer. If SCSI would be required to be involved in error handling for dropped packets, it would be disastrous for SCSI Stream Devices (ex: tape backup session). This is due to the fact that SCSI Stream Devices have stateful behavior.

>
> In the LAN, TCP packets are not generally lost and we should
> be comparable
> to FC.
> Over WAN, can have packet loss and resulting complications,
> but that is no
> longer competing with FC
> (which doesn't exist at all in the WAN).

The people working on the FC-BB specification would probably refute the statement that FC does not exist at all in the WAN.

> ...

> Naming:
>
> What have most of us agreed to in the meantime?
> We do not presently attempt to name LUNs.
> We name targets with URL syntax
> scsi://host_name[/virtual_target_name]

This may be more appropriately scsi://host_name[/virtual_device_name]

>
> Multiple views can also be achieved by using different
> host_names for the
> same target.

Perhaps same device, rather than same target.

>
> Further rehashing and discussion about virtual_target_name (=
> view, = VSDP
> == Virtual Service Delivery Port).

Careful about the terminology here - under SAM and SAM-2, the term Target is not synonymous with Service Delivery Port. Indeed, a SCSI Device consists of (1 Target, or 1 Initiator, or both), and (a nonzero number of Service Delivery Ports).

Joe Breher
Exabyte Corp