SAS SMP frame type errors

Elliott, Robert (Server Storage) Elliott at hp.com
Thu Jan 30 15:21:10 PST 2003


* From the T10 Reflector (t10 at t10.org), posted by:
* "Elliott, Robert (Server Storage)" <Elliott at hp.com>
*
This is a multi-part message in MIME format.

------_=_NextPart_001_01C2C8B6.45D3FD1F
Content-Type: text/plain;
	charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

The SMP frame type field in the first byte of an SMP frame (see 9.4 in
sas-r03b) contains either:=20
40h SMP_REQUEST    (initiator port to target port)=20
41h SMP_RESPONSE  (target port to initiator port)=20

What if the SMP target port receives a frame where this field is not =
set
to 40h?=20

One letter ballot comments suggests that an SMP_RESPONSE shall be
returned with a function result of SMP FUNCTION FAILED.  I think that
simply discarding the frame is better.  That's what SSP specifies for
unknown frame types.  The same rule would apply to SMP initiators
receiving bad frames.

One slight problem with discarding, though: the SMP link layer on the
target side only accepts one frame then expects to send something back.
It won't know the SMP transport layer has chosen to discard the frame
and plans no reply.  We could require the SMP transport layer to break
the connection if it discards the frame so we don't leave the SMP link
layer waiting for a frame to send. =20

--=20
Rob Elliott, elliott at hp.com=20
Hewlett-Packard Industry Standard Server Storage Advanced Technology=20
 <https://ecardfile.com/id/RobElliott>
https://ecardfile.com/id/RobElliott=20




------_=_NextPart_001_01C2C8B6.45D3FD1F
Content-Type: text/html;
	charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">

SAS SMP frame type errors The SMP frame type field in the first = byte of an SMP frame (see 9.4 in sas-r03b) contains either: 
40h SMP_REQUEST    = (initiator port to target port) 
41h SMP_RESPONSE  (target port = to initiator port) What if the SMP target port receives a = frame where this field is not set to 40h? One letter ballot comments suggests = that an SMP_RESPONSE shall be returned with a function result of SMP = FUNCTION FAILED.  I think that simply discarding the frame is = better.  That's what SSP specifies for unknown frame types.  = The same rule would apply to SMP initiators receiving bad = frames. One slight problem with discarding, = though: the SMP link layer on the target side only accepts one frame = then expects to send something back.  It won't know the SMP = transport layer has chosen to discard the frame and plans no = reply.  We could require the SMP transport layer to break the = connection if it discards the frame so we don't leave the SMP link = layer waiting for a frame to send.  -- 
Rob Elliott, elliott at hp.com 
Hewlett-Packard Industry Standard = Server Storage Advanced Technology 
https://ecardfile.com/id/RobElliott 


------_=_NextPart_001_01C2C8B6.45D3FD1F--




More information about the T10 mailing list