SAS questions

Elliott, Robert (Server Storage) Elliott at hp.com
Fri Dec 6 15:29:48 PST 2002


* From the T10 Reflector (t10 at t10.org), posted by:
* "Elliott, Robert (Server Storage)" <Elliott at hp.com>
*
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1. From the transport layer to the port layer, frames are marked as
Interlocked or Non-Interlocked based on their frame type - only DATA
frames are Non-Interlocked.
=20
The port layer determines the order frames are sent to a given phy's
link layer and knows when connections are opened and closed.  It
determines if a Non-interlocked frame is a candidate to be pipelined on
the wire (the connection had to stay open from the previous frame, and
the previous frame had to also be Non-Interlocked with the same tag). =20
=20
The port layer marks the frame it sends to the link layer with Balance
Required if pipelining is not allowed, or Balance Not Required if it =
is.
=20
The link layer uses that to determine if it needs to wait for ACK/NAK
balance before transmitting the frame.
=20
2. An active port contains one or more phys; once active, the port =
layer
starts accepting requests from the transport layer.  If a phy loses
dword synchronization and drops out, the port stops using that phy.  If
all the phys disappear, the port layer rejects any pending frame
requests from the transport layer with Transmission Status (No Phys In
Port).  If some phys are still left, it continues accepting and working
on frame requests.
=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


-----Original Message-----
From: Dennis Moore [mailto:dmoore at ix.netcom.com]=20
Sent: Friday, December 06, 2002 2:57 PM
To: t10 at t10.org
Subject: SAS questions


In going over the Port Layer Clause 8.3.3.1.1 there is reference made =
to
"Balance Required" and "Balance Not Required". I have been unable to
find the meaning. Also, in Clause 8.3.2 there is reference made to
"Transmission Status (No Phys In Port)". What is the meaning of "No =
Phys
In Port"?=20
Thanks,
dmoore at ix.netcom.com =20
=20


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Message 1.=20 >From the transport layer to the port layer, frames are marked=20 as Interlocked or Non-Interlocked based on their frame type - only = DATA=20 frames are Non-Interlocked.
  
 The=20 port layer determines the order frames are sent to a given phy's link = layer and=20 knows when connections are opened and closed.  It determines if a=20 Non-interlocked frame is a candidate to be pipelined on the wire (the = connection=20 had to stay open from the previous frame, and the previous frame had to = also be=20 Non-Interlocked with the same tag).  
 
 The port layer=20 marks the frame it sends to the link layer with Balance Required if = pipelining=20 is not allowed, or Balance Not Required if it=20 is.
  
 The link layer uses that to determine if it = needs to=20 wait for ACK/NAK balance before transmitting the=20 frame.
  
 2. An=20 active port contains one or more phys; once active, the port layer = starts=20 accepting requests from the transport layer.  If a phy loses=20 dword synchronization and drops out, the = port stops=20 using that phy.  If all the phys disappear, the port = layer rejects any=20 pending frame requests from the transport layer with Transmission = Status (No=20 Phys In Port).  If some phys are still left, it continues = accepting and=20 working on frame requests.
  
 -- = 
Rob Elliott, = elliott at hp.com=20 
Hewlett-Packard = Industry Standard=20 Server Storage Advanced Technology 
https://ecardfile.com/id/Ro= bElliott=20 


-----Original Message-----
From: = Dennis Moore=20 [mailto:dmoore at ix.netcom.com] 
Sent: Friday, December 06, = 2002 2:57=20 PM
To: t10 at t10.org
Subject: SAS=20 questions


 In going over the Port Layer Clause = 8.3.3.1.1=20 there is reference made to "Balance Required" and "Balance Not = Required". I=20 have been unable to find the meaning. Also, in Clause 8.3.2 there is = reference=20 made to "Transmission Status (No Phys In Port)". What is the meaning = of "No=20 Phys In Port"? 
Thanks,
 dmoore at ix.netcom.com  


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