ISCSI: negotiation of the use of the Urgent Pointer

[Matt Wakeley <matt_wakeley@agilent.com>]

Silvano Gai wrote:

> I don't think that changing MUST to SHOULD or MAY is going to solve the problem. If the two ends do not agree whether using or not the Urgent Pointer, you may end up in a very unoptimized situation.
>
> For Example:
> - Server S has iSCSI in HW and supports UP (Urgent Pointer)
> - Client C has iSCSI in SW (e.g. a laptop)
>
> When S sends to C, C fails the "header prediction test" and goes to the slow path, since UP is present.

> I don't think we want to implement UP negotiation. Correct?

There could be an Urgent Pointer use negotiation mechanism, where if an iSCSI implementation indicates during login that it wants (requires) to receive the urgent pointer, the other side must send it,
even if it does not want to receive it.

Using your example above, C would send iSCSI messages to S using the urgent pointer, but S would not use the urgent pointer when sending iSCSI messages to C.

Matt Wakeley
Agilent Technologies


>
>
> Cheers
>
> -- Silvano
>
> Silvano Gai
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