Ex Parte Chayat

Board of Patent Appeals and Interferences

Sep 13, 2010

10140730 (B.P.A.I. Sep. 13, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
10/140,730 05/07/2002 Ronen Chayat MP0143 6581
26703 7590 09/14/2010
HARNESS, DICKEY & PIERCE P.L.C.
5445 CORPORATE DRIVE
SUITE 200
TROY, MI 48098
EXAMINER
REFAI, RAMSEY
ART UNIT PAPER NUMBER
3627
MAIL DATE DELIVERY MODE
09/14/2010 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte RONEN CHAYAT
____________

Appeal 2009-009094
Application 10/140,730
Technology Center 3600
____________

Before: MURRIEL E. CRAWFORD, ANTON W. FETTING, and JOSEPH
A. FISCHETTI, Administrative Patent Judges.

CRAWFORD, Administrative Patent Judge.

DECISION ON APPEAL1

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, or for filing a request for rehearing,
as recited in 37 C.F.R. § 41.52, begins to run from the “MAIL DATE”
(paper delivery mode) or the “NOTIFICATION DATE” (electronic delivery
mode) shown on the PTOL-90A cover letter attached to this decision.

Appeal 2009-009094
Application 10/140,730

2
STATEMENT OF THE CASE
This is an appeal from the final rejection of claims 1-12, 14-25, 27-38,
40-51, 53-64, 66-77, 79-90, 92-103, 105-116, 118-129, 131-142, and 144-
1552. We have jurisdiction to review the case under 35 U.S.C. §§ 134 and 6
(2002).
The claimed invention is directed to systems and methods for
implementing data flow control schemes in long-distance data
communication links (Spec., para. [0001]). Claim 1, reproduced below, is
further illustrative of the claimed subject matter.
1. A network device comprising:
a media access controller comprising
a first buffer to store data received from a further
network device, and
a transmitter to transmit the data from the first buffer;
and
a link-layer device to receive the data transmitted by the
media access controller, the link-layer device comprising a
second buffer to store the data received from the media access
controller;
wherein the link-layer device asserts status signals
indicating an amount of the data in the second buffer;
wherein the transmitter transmits the data from the first
buffer to the link-layer device in response to the status signals
asserted by the link-layer device; and
wherein the media access controller further comprises a
controller to send flow-control signals to the further network
device based on the status signals asserted by the link-layer

2 Appellant does not seek review of the rejection of dependent claims 13, 26,
39, 52, 65, 78, 91, 104, 117, 130, 143, and 156 (App. Br. 11), but does list
all claims 1-156 as being the claims on appeal on page 3 of the Appeal Brief.
Therefore, these claims rise or fall with the claims on which they depend.
See, 37 C.F.R. § 41.37(c)(1)(vii) (2010).

Appeal 2009-009094
Application 10/140,730

3
device, thereby causing the further network device to regulate
the amount of the data sent from the further network device to
the network device in response to the flow-control signals.
The references of record relied upon by the Examiner as evidence of
obviousness are:
Ramakrishnan US 6,167,029 Dec. 26, 2000

Claims 1-12, 14-25, 27-38, 40-51, 53-64, 66-77, 79-90, 92-103, 105-
116, 118-129, 131-142, and 144-155 stand rejected under 35 U.S.C. § 102(b)
as anticipated by Ramakrishnan.
We REVERSE.

ISSUE
Did the Examiner err in asserting that Ramakrishnan discloses the
subject matter of claims 1-12, 14-25, 27-38, 40-51, 53-64, 66-77, 79-90, 92-
103, 105-116, 118-129, 131-142, and 144-155?

FINDINGS OF FACT
Ramakrishnan
Figure 4 of Ramakrishnan is illustrated below.
Appeal 2009-009094
Application 10/140,730

4

Figure 4 of Ramakrishnan is illustrated above.
Ramakrishnan discloses, in Figure 4, a diagrammatic representation of
components which are included in a data link layer 400. The data link layer
400 includes a MAC control client 402 (e.g., logic link control (LLC)), a
media access control (MAC) control sublayer 404, and a media access
control (MAC) 406. The MAC control client 402 is generally a software
function that is responsible for attaching control information to the data
being transmitted from a network layer to the MAC 406. The MAC control
client 402 sends data and control information to the MAC control sublayer
Appeal 2009-009094
Application 10/140,730

5
404 and also receives data and control information from the MAC control
sublayer 404. The MAC 406 is coupled to a physical layer and is generally
responsible for scheduling, transmitting, and receiving data over a link. The
MAC control sublayer 404 follows the Institute of Electrical and Electronic
Engineers (IEEE) standards defined in section 802.3x, which defines
standardized flow control. The MAC control sublayer 404 provides transmit
frames (TX_FRAME) to the MAC 406 as well as receives receive frames
(RX_FRAME) from the MAC 406. The MAC control sublayer 404 is also
the portion of the data link layer 400 that understands and implements pause
frames (col. 6, ll. 16-37).
A pause frame is a specific frame (or packet) that is used to facilitate
flow control with full-duplex communications. The pause frame is
transmitted from one station to another to inform that station that data
transmission should be temporarily stopped. Upon receiving the pause
frame, the station that had been transmitting is instructed to stop transmitting
for a period of time (col. 6, ll. 38-45).
Figure 6 is illustrated below.

Appeal 2009-009094
Application 10/140,730

6

Figure 6 is illustrated above.
Figure 6 is a diagrammatic representation of flow control system 600.
The flow control system 600 is provided within an integrated circuit that
also includes the MAC (e.g., MAC 406). In other words, the buffers for
transmission and reception as well as the MAC and the MAC control are
contained within a single integrated circuit. This arrangement yields what is
referred to as integrated flow control (col. 7, ll. 7-15).
The flow control system 600 includes a MAC control 602, a transmit
buffer 604, and a receive buffer 606. Typically, the buffers 604 and 606 are
FIFOs. The MAC control 602 is coupled with the receive buffer 606 and the
transmit buffer 604. When frames (more generally, data) from a sending
station are received at a receiving station, the received frames are buffered in
the receive buffer 606. Further, frames (more generally, data) outgoing from
a sending station to a receiving station are buffered in the transmit buffer
604 (col. 7, ll. 16-25).
The received buffer 606 is associated with a level indicator that is able
to indicate the level of utilization of the storage capacity of the buffer.
Specifically, the level indicator signals two levels, an almost full (AF) level
608 and an almost empty (AE) level 610. The AF level 608 indicates that
the amount of data stored in the receive buffer 606 is nearing its maximum
capacity. As an example, the AF level 608 can indicate that the receive
buffer 606 is at 95% capacity. Similarly, the AE level 610 indicates that the
amount of data stored in the receive buffer 606 is nearing its minimum
capacity. As an example, the AE level 610 can indicate that the receive
buffer 606 is at 5% capacity. For example, if the receive buffer were 8
Appeal 2009-009094
Application 10/140,730

7
kilobytes (kB), then the AF level could be about 7.6 kB and the AE level
could be about 0.4 kB (col. 7, ll. 25-40).
When the amount of data stored in the receiving buffer 606 reaches
the AF level 608, then the MAC control 602 produces and issues a pause
frame to a sending station to inform to the sending station that data
transmission (to the receiving buffer 606) should temporarily be stopped.
The production and issuance of the pause frame are automatically performed
by the MAC control 602. (Col. 7, ll. 41-47).
Transmit buffer 604 has the same corresponding features as receive
buffer 606 (col. 8, ll. 7-20).

ANALYSIS
We are persuaded that the Examiner erred in asserting that
Ramakrishnan discloses the subject matter of claims 1-12, 14-25, 27-38, 40-
51, 53-64, 66-77, 79-90, 92-103, 105-116, 118-129, 131-142, and 144-155
(App. Br. 11-21; Reply Br. 2-4). Initially, it is unclear what the Examiner
asserts in Ramakrishnan corresponds to the media access controller (MAC)
and link layer device (LLD) recited in independent claims 1, 14, 27, 40, 53,
66, 79, 92, 105, 118, 131, and 144. As best as we can tell, the Examiner is
asserting that flow control system 600 in Figure 6 and MAC 406 in Figure 4
of Ramakrishnan corresponds to the recited MAC, and a combination of
MAC control client 402 and MAC control sublayer 404 corresponds to the
recited LLD (Exam’r’s Ans. 7-9). Flow control system 600 includes buffers
604, 606 which monitor their own capacity and, through another component
of system 600, send pause/resume signals to other devices to/from which
they are sending/receiving data (Fig. 6; col. 7, l. 47; col. 8, ll. 7-20). The
Appeal 2009-009094
Application 10/140,730

8
Examiner appears to be asserting that these buffers 604, 606 correspond to
the recited first buffer.
Figure 4 of Ramakrishnan discloses that data is exchanged between
MAC 406 and MAC control sublayer 404, and between MAC control
sublayer 404 and MAC control client 402 (Fig. 4; col. 6, ll. 16-45).
Accordingly, at least one of MAC control sublayer 404 and MAC control
client 402 is presumed to have a buffer that corresponds to the recited
second buffer. Buffer control commands are also exchanged between MAC
control client 402 and MAC control sublayer 404, as shown in Figure 4, and
between MAC control sublayer 404 and MAC 406 via TX_FRAME and
RX_FRAME.
Independent claim 1 recites “wherein the media access controller
further comprises a controller to send flow-control signals to the further
network device based on the status signals asserted by the link-layer device.”
Independent claims 14, 27, 40, 53, 66, 79, 92, 105, 118, 131, and 144 recite
similar subject matter. Thus, when applied to Figure 4 of Ramakrishnan,
MAC 406 needs to be able to send flow-control signals to “(TO
PHYSICAL)” based on readings from buffer control signals CONTROL
between MAC control client 402 and MAC control sublayer 404 or
TX_FRAME and RX_FRAME. However, the Examiner has not shown that
this is the case. The Examiner has only shown that MAC 406/602 sends
flow-control signals to “(TO PHYSICAL)” based on the capacity of buffers
604, 606, and that MAC control client 402/MAC control sublayer 404 sends
flow-control signals to MAC 406/604 based upon the capacity of the buffers
in MAC control client 402/MAC control sublayer 404. In other words, the
Examiner has not shown that the flow-control signals to “(TO PHYSICAL)”
Appeal 2009-009094
Application 10/140,730

9
are based on buffer capacity signals from MAC control client 402/MAC
control sublayer 404. As far as we can tell, the two flow-control signals are
decoupled, and thus do not meet the aforementioned portion of independent
claim 1. For the same reasons, we do not sustain the rejection of
independent claims 14, 27, 40, 53, 66, 79, 92, 105, 118, 131, and 144, or
respective dependent claims 2-12, 15-25, 28-38, 41-51, 54-64, 67-77, 80-90,
93-103, 106-116, 119-129, 132-142, and 145-155.

REVERSED

hh

HARNESS, DICKEY & PIERCE P.L.C.
5445 CORPORATE DRIVE
SUITE 200
TROY, MI 48098