Re: Option or mandatory CRC in MPA

At 07:41 PM 4/7/2003 -0400, Stephen Bailey wrote:
>Hi,
>
>It seems to me that one significant items holding up RDDP and
>specifically MPA, is whether CRC should be optional or mandatory.
>
>At the last IETF David said he would be uncomfortable requiring CRC
>protection if a key current client protocol (NFS) is not going to
>require the protection when not running on RDDP.  The primary argument
>for this is to allow RDDP to cross the transition hurdle more easily
>by not punishing software clients.
>
>A majority of implementors want CRC, so clearly many implementations
>will support it. There's incentive to implement it, and the penalty in
>hardware implementations is negligable.
>
>Implementations that do CRC can generate always and check optionally,
>which is easy.
>
>Rather than waiting for NFSv4 to settle the argument, it seems we
>could push ahead with a reserved spot in the payload, and negotiable
>checking.

In some discussions after the meeting with people in NFSv4, it seemed they 
may be fine with RDDP doing the CRC and letting it be optional at their 
layer.  Agree that NFSv4 workgroup needs to make a recommendation here but 
it is not clear to me that having it required is a major issue at all.  The 
only issue raised was why do it in both layers?   If NFSv4 can make it 
optional similar to how iSCSI can make digests optional then this can be 
resolved as a ULP issue allowing the RDDP implementations to be simplified