Ex Parte Sadot et al

Board of Patent Appeals and Interferences

Jan 9, 2008

09915609 (B.P.A.I. Jan. 9, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte EMEK SADOT and EPHRAIM ZILBERSHTEIN
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Appeal 2007-3350
Application 09/915,609
Technology Center 2100
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Decided: January 9, 2008
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Before HOWARD B. BLANKENSHIP, ST. JOHN COURTENAY III, and
STEPHEN C. SIU, Administrative Patent Judges.

SIU, Administrative Patent Judge.

DECISION ON APPEAL
I. STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
Final Rejection of claims 1-22. We have jurisdiction under 35 U.S.C.
§ 6(b). We reverse.
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A. INVENTION
The invention at issue involves pre-assigning different groups of
secure sockets layer (SSL) session identifiers to different servers in a server
farm (Spec. 3). In particular, a load balancer includes a table that stores lists
of ranges of SSL session IDs assigned to each server (id. 6) and each server
includes a record that identifies SSL session IDS that may be used by the
server in identifying SSL sessions. (Id.)

B. ILLUSTRATIVE CLAIMS
Claims 1 and 19, which further illustrate the invention, follow.
1. A method of load balancing messages to servers of a server
farm, by a load balancer, comprising:
configuring the load balancer with information specifying a pre-
assignment of different groups of session ID values to respective ones of the
servers, each of said servers being operative to assign session ID values from
its associated one of the pre-assigned groups to sessions handled by that
server;
determining, by the load balancer, for at least some client messages
including a non-empty session ID field, which server or sub-group of servers
is associated with the ID in the ID field, responsive to the configured
information; and
selecting, by the load balancer, a server to receive each of the at
least some client messages, at least partially responsive to the
determination.

19. A load balancer, comprising:
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a memory unit adapted to store configured information specifying a
pre-assignment of different groups of session ID values to respective ones of
the servers, each of said servers being operative to assign session ID values
from its associated one of the pre-assigned groups to sessions handled by
that server;
an input interface adapted to receive client messages; and
a load balancing unit which is adapted to select a server to
receive at least one of the client messages, at least partially responsive
to the contents of the memory unit, and to forward the at least one of
the client messages to the selected server.

C. REJECTION
Claims 1-5, 7-12 and 14-22 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over U.S. Patent No. 6,772,333 (“Brendel”), U.S. Patent
No. 5,774,668 (“Choquier”), and U.S. Patent No. 6,138,120 (“Gongwer”).
Claims 6 and 13 stand rejected under 35 U.S.C. § 103(a) as being
unpatentable over Brendel, Choquier, Gongwer, and U.S. Patent No.
6,611,498 (“Baker”).

II. ISSUES
Appellants dispute the Examiner’s conclusion of obviousness of claim
1 and argue that Brendel, Choquier, and Gongwer fail to teach all claim
limitations. In particular, Appellants argue that the combination of
references fails to disclose the load balancer with information specifying a
pre-assignment of different groups of session ID values to respective ones of
the servers, each of said servers being operative to assign session ID values
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from its associated one of the pre-assigned groups to sessions handled by
that server (App. Br. 5). Claim 19 recites a load balancer with a memory
unit that stores information specifying a pre-assignment of different groups
of session ID values to respective ones of servers, each of the servers being
operative to assign session ID values from its associated one of the pre-
assigned groups to sessions handled by that server. Appellants argue
patentability of claim 19 because claim 19 is “similar to . . . independent
claim 1” (App. Br. 7).
In response, the Examiner asserts that “the Brendel-Choquier-
Gongwer combination discloses the capability for the selection of a session
identifier from a pool of identifiers.” (Ans. 20).
We find the evidence in the record before us is insufficient to support
the Examiner’s conclusion of obviousness for claims 1 and 19. The
Examiner cites Choquier and Gongwer as disclosing “the selection of a
session identifier value. (see Choquier col. 15, lines 28-41: load management
system utilizing a range of values assigned to each entity (i.e., server,
processor) and utilized in the generation of a calculated ID value (i.e.,
session ID or session information))” (Ans. 20) and “the capability for the
selection of a session identifier from a pool of identifiers. (see Choquier col.
15, lines 28-41 . . . ) . . . (see Gongwer col. 2, lines 2-5; col. 9, lines 52-54;
col. 12, lines 54-57; col. 12, lines 62-65: session identifier selected from
pool of unassigned session identifiers)” (Id.)
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However, we find that Choquier discloses a technique of using ranges
of integer values for selecting a server in which servers with higher available
processing power are selected preferentially over servers with lower
processing power (Choquier, col. 15, ll. 22-50). Gongwer further discloses
servers assigning session handles that are selected from a pool of unassigned
session handles (Gongwer, col. 2, ll. 2-5). Additional cited passages in the
Gongwer reference (e.g., col. 9, lines 52-54; col. 12, lines 54-57; and col. 12,
lines 62-65) also disclose assigning session handles that are selected from a
pool of session handles.
Although Gongwer discloses selecting session handles from a pool of
session handles and assigning the selected session handles to sessions, the
Examiner fails to establish that Gongwer also discloses pre-assigning
different groups of session identifier values to respective servers where each
of the servers assign session identifiers to sessions from the corresponding
pre-assigned group of session identifiers or that the pool of session handles
are pre-assigned in different groups to respective servers.
We also find that Gongwer fails to disclose a load balancer as recited
in claim 19 in which the load balancer comprises a memory unit that stores
information specifying a pre-assignment of different groups of session ID
values to respective ones of servers, each of the servers assigning session ID
values from its associated one of the pre-assigned groups to sessions handled
by that server. Instead, Gongwer appears to disclose assigning session
handles to sessions where the session handles are selected from a group.
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The Examiner has not shown that the group of session handles from which
session handles are selected in Gongwer is pre-assigned in different groups
to respective servers.
Also, we disagree with the Examiner’s finding that Choquier discloses
a “load management system utilizing a range of values assigned to each
entity (i.e., server, processor) and utilized in the generation of a calculated
ID value (i.e., session ID or session information)).” (Ans. 20). Rather,
Choquier appears to disclose assigning a range of consecutive integer values
to servers where the size of the range of integer values is proportional to the
processing power of the respective server. Choquier does not disclose that
the assigned range of integer values is assigned as a session identifier.
Thus, we find that the combination of Choquier and Gongwer fails to
disclose a load balancer pre-assigning different groups of session ID values
to respective servers and each server assigning session ID values from a
corresponding pre-assigned group to sessions handled by the server.
Therefore, we reverse the rejection of claims 1 and 19 and of claims
2-18 and 20-22, which depend therefrom.

III. ORDER
In summary, the rejection of claims 1-22 under § 103(a) is reversed.

REVERSED
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