Ex Parte Pradhan

Patent Trial and Appeal Board

Mar 24, 2014

11491362 (P.T.A.B. Mar. 24, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte TANMAY KUMAR PRADHAN
__________

Appeal 2011-011669
Application 11/491,362
Technology Center 2100
__________

Before ERIC GRIMES, JEFFREY N. FREDMAN, and
ZHENYU YANG, Administrative Patent Judges.

FREDMAN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal1 under 35 U.S.C. § 134 involving claims to a method
and apparatus for selecting a cluster in a group of nodes. The Examiner
rejected the claims as obvious. We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.

1 Appellant identifies the Real Party in Interest as Hewlett-Packard
Development Company, L.P. (see App. Br. 2).
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Statement of the Case
Background
“A cluster is made up [of] a group of interconnected computers
(nodes) running cluster software which enables the group to behave like a
single computer. The nodes communicate with each other via a set of
network connections referred to as a cluster interconnect” (Spec. 1, ll. 13-
16). The Specification teaches that in “the event of a failure in the cluster
interconnect, the cluster becomes split into subgroups of nodes . . . The
largest candidate cluster is self selected to continue to provide the cluster
functions and services” (Spec. 1, ll. 22-27). According to the Specification
“if two candidate clusters are the same size then this method can result in
more than one cluster considering themselves to be the largest. In this case
more than one cluster can access[ ] the cluster data set and compromise the
integrity of that data” (Spec. 1, ll. 29-32).
The Claims
Claims 1-11, 13-20, 23 and 24 are on appeal2. Claim 1 is
representative and reads as follows:
1. A method of selecting a cluster in a group of nodes, said
method comprising the steps of:
a) assigning a token to a first node in the group of nodes;
b) identifying subgroups, from among the group of nodes, that
are interconnected; and
c) if two largest subgroups, from among the identified
subgroups, comprise equal numbers of nodes, then selecting as the

2 Claims 21 and 22 were indicated as objected to as being
dependent upon a rejected base claim, but otherwise allowable
(Ans. 3).
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cluster a subgroup containing the node to which said token is
assigned.
The Issues
A. The Examiner rejected claims 1-8, 13-18, 20, 23 and 24 under 35
U.S.C. § 103(a) as obvious over Wipfel3 and Moiin4 (Ans. 4-9).
B. The Examiner rejected claim 9 under 35 U.S.C. § 103(a) as obvious
over Wipfel, Moiin and Winchell5 (Ans. 9-10).
C. The Examiner rejected claims 10, 11 and 19 under 35 U.S.C. § 103(a)
as obvious over Wipfel, Moiin and Rao6 (Ans. 10-12).
Because the rejections turn on the same issue, we will consider these
rejections together.
The Examiner finds that Wipfel teaches a method of selecting a
cluster in a group of nodes (Ans. 4). The Examiner finds that Wipfel teaches
assigning a token to a first node in a group of nodes, specifically finding that
“quorum is the token and SCSI is Small Computer System Interface, is a set
of standards for physically connecting and transferring data between
computers” (id.). The Examiner finds the Wipfel teaches differentiating
between the two largest identified subgroups of nodes comprising equal
numbers of nodes by selecting the subgroup containing the node to which is
assigned the token as the cluster (id.).

3 Wipfel et al., US 2005/0268154 A1, published Dec. 01, 2005.
4 Moiin et al., US 6,449,641 B1, issued Sep. 10, 2002.
5 Winchell, US 2003/0187927 A1, published Oct. 02, 2003.
6 Rao et al., US 2007/0016822 A1, published Jan. 18, 2007.
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However, the Examiner finds that Wipfel does not teach “identifying
subgroups, from among the group of nodes, which are interconnected” (id.
at 4).
The Examiner finds that Moiin teaches “identifying subgroups, from
among the group of nodes, which are interconnected” (id.).
The Examiner finds it obvious “to incorporate the teaching of Moiin
in to the method of Wipfel . . . to provide a mechanism[ ] to keep track of the
member nodes and to coordinate the reconfiguration of the cluster
applications and services when the cluster membership changes and provide
a flexible algorithm that would maximize the cluster availability and
performance as viewed by the user” (id. at 5).
The issue with respect to each of the rejections is: Does the evidence
of record support the Examiner’s conclusion that Wipfel and Moiin render
the claims obvious?
Findings of Fact
1. Wipfel teaches “a system and method for detecting and
resolving a partition condition in a cluster of computers” (Wipfel 1 ¶ 0002).
2. Wipfel teaches that
[t]he resolution of cluster partition is implemented by a static
algorithm where the partition with the majority of nodes survives and
the nodes in the minority partition eat the poison pill. In case of a
tiebreaker, the following algorithm is implemented.

First, in case of a two-node cluster, the node that is connected to the
local area network wins the tiebreaker and the node which is
disconnected from the local area network loses the tiebreaker.

(Wipfel 5 ¶ 0068-0069).
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3. Wipfel teaches
[o]ne implementation of a cluster and quorum involves allocating
votes to various cluster members. A quorum value is calculated from
all the outstanding votes. If the current members of a cluster own
more than "quorum" number of votes, the cluster is allowed to
function. Otherwise, the cluster goes into a paused state until more
cluster members rejoin.

(Wipfel 5 ¶ 0074).
4. Wipfel teaches that
[y]et another approach to solve this partitioned cluster problem is by
assigning a SCSI disk as a quorum resource. Every node in the cluster
can arbitrate for the quorum device and gains exclusive access to a
disk by successful issuing a Reserve SCSI command. It releases the
ownership by issuing the Release SCSI command. Also any node can
issue a SCSI bus reset which forces the quorum device and all other
devices on the SCSI bus to reset (thus releases the existing
ownership). . . This protocol uses the SCSI bus reset, Release and
Reserve SCSI commands. The problem with this implementation is
that it does not scale. The SCSI bus reset forces all the devices
including the quorum device to reset.

The current embodiment does not use the SCSI bus reset and
Reserve/Release SCSI commands. It only issues the Read/Write
commands to the device, which contains the Split-Brain partition.

(Wipfel 6 ¶ 0075-0076).
5. Wipfel teaches that
[p]er node information includes: a signature; nodeNumber, heartBeat;
nodeState; extNodeState; groupEpoch; sbdLock; nodeBitMask; and
nodeActivity. When the SBD partition is created, a valid signature is
kept in each slot. The validity of the signature can be verified before
a node can join the cluster. If the valid signature does not exist, the
node can be prevented to ever join the cluster.

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(Wipfel 5 ¶ 0056).
6. Moiin teaches that
[w]ith the failures described above, the cluster membership can be
partitioned into two or more fully-connected subsets of nodes having a
majority of the votes, a minority of the votes, or exactly half of the
votes. The first two cases may be resolved by only allowing a subset
having a majority vote to form the next generation of the cluster. In
the latter case, a tie breaking mechanism must be employed.

(Moiin col. 4, l. 66 – col. 5, l. 5).
7. Moiin teaches that
[e]ach node i keeps the total number of the nodes that are in its current
view of the cluster membership, whether agreed or proposed, in a
local variable Ni. Note that Ni is subject to the following rules during
the execution of the membership algorithm: . . . (d) The quorum at the
end of the membership algorithm is decided on this notion of Ni.

(Moiin col. 8, l. 66 – col. 9, l. 13).
Principles of Law
“‘[R]ejections on obviousness grounds cannot be sustained by mere
conclusory statements; instead, there must be some articulated reasoning
with some rational underpinning to support the legal conclusion of
obviousness.’” KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007)
citing In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006).
Analysis
Appellant contends that “the Examiner cites [Wipfel’s] paragraphs
[0074] and [0075] as teaching element (a)” (i.e. assigning a token to a first
node in the group of nodes) (App. Br. 7). Appellant further contends that
Wipfel
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discusses using the SCSI disk as a quorum resource as a
manner of preventing a partitioned cluster from forming.
The quorum resource manner uses a reserve SCSI command
and a release SCSI command. However, paragraph [0076]
specifically states that the reserve and release commands are
not used in the current embodiment of Wipfel. Thus, the
embodiment of Wipfel cannot use the teachings of
paragraph [0075], specifically the quorum resource.

(App. Br. 7). Appellant further contends that “Moiin is not relied upon in
the Office Action as teaching this element” (id.).
The Examiner finds that “according to the applicant’s specification
quorum is the token, and SCSI is Small Computer System Interface, [which]
is a set of standards for physically connecting and transferring data between
computers” (Ans. 13; FF 3, 4). The Examiner also finds that Wipfel teaches
“[w]hen the SBD (Split Brain Detection) partition is created; a valid
signature is kept in each slot. A valid signature is the token and slot is the
cluster” (id., FF 5). The Examiner finds that Moiin teaches a token being a
“global variable” (Ans. 22-23).
We find that Appellant has the better position. The Examiner
identifies the quorum resource management of the SCSI and the “valid
signature” as satisfying the “assigning a token to a first node” limitation of
claim 1 (Ans. 13). However, as Appellant points out, the quorum resource
teaching cannot be used for the teaching of an assigned token to the node
(App. Br. 7-8, Rep. Br. 3) because Wipfel describes the quorum as the
number of votes, among cluster members, that is required in order for a
cluster to be allowed to function (Wipfel 5 ¶ 0074, FF 3). In addition,
Wipfel teaches “the node that is connected to the local area network wins the
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tiebreaker and the node which is disconnected from the local area network
loses the tiebreaker” (FF 2). Consequently, the Examiner has not established
how either the quorum resource or valid signature information is an assigned
token. Nor has the Examiner established how either the quorum resource or
valid signature is utilized as a “token” to select the subgroup containing the
node if the two largest subgroups comprise an equal number of nodes as
required by claims 1, 13 and 20. Thus, the Examiner has not provided
sufficient evidence that Wipfel or Moiin alone or in combination teach all
the claim limitations of claims 1, 13 and 20, and therefore, has not met the
burden of providing sufficient evidence for a case of obviousness.
Conclusion of Law
The evidence of record does not support the Examiner’s
conclusion that Wipfel and Moiin render the claims obvious.
SUMMARY
In summary, we reverse the rejection of claims 1-8, 13-18, 20, 23 and
24 under 35 U.S.C. § 103(a) as obvious over Wipfel and Moiin.
We reverse the rejection of claim 9 under 35 U.S.C. § 103(a) as
obvious over Wipfel, Moiin and Winchell.
We reverse the rejection of claims 10, 11 and 19 under 35 U.S.C.
§ 103(a) as obvious over Wipfel, Moiin and Rao.

REVERSED

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