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Brocade Communications Systems, Inc., A Delaware Corporation v. A10 Networks

January 6, 2012


The opinion of the court was delivered by: Lucy H. Koh For the Northern District of California

ORDER CONSTRUING DISPUTED CLAIM TERMS OF U.S. PATENT NOS. 7,647,427; 7,716,370; 7,558,195; 7,454,500; 7,581,009; 7,657,629; 7,584,301; 7,840,678; and 5,875,185

Plaintiffs Brocade Communications Systems, Inc. and Foundry Networks, LLC (collectively "Brocade") bring this action against A10 Networks, Inc. ("A10"), and the following 18 individuals: Lee Chen, Rajkumar Jalan, Ron Szeto, David Cheung, Liang Han, and Steve Hwang. 19

Brocade asserts claims of patent and copyright infringement as well as trade secret 20 misappropriation, breach of contract, breach of fiduciary duty, breach of duty of loyalty, 21 interference with prospective economic advantage, interference with contract, and unfair 22 competition under Cal. Bus. & Prof. Code §§ 17200 et seq. A10 counterclaimed that several of 23

Brocade's products infringed one of A10's patents. The parties now seek construction of ten 24 disputed terms used in the claims of the following patents-in-suit: U.S. Patent Nos. 7,647,427 B1 25 ("'427 Patent"); 7,716,370 ("'370 Patent"); 7,558,195 ("'195 Patent"); 7,454,500 ("'500 Patent"); 26 7,581,009 ("'009 Patent"); 7,657,629 ("'629 Patent"); 7,584,301 ("'301 Patent"); 7,840,678 ("'678 27 Patent"); and 5,875,185 ("'185 Patent"). The Court held a technology tutorial on December 12, 28 2011, and a claim construction hearing on December 19, 2011. The Court has reviewed the claims, specifications, and other relevant evidence, and has considered the briefing and arguments of the 2 parties. The Court now construes the terms at issue.

patents. 7


A.Prosecution History

At issue in this claim construction are four families of Brocade's patents and one of A10's Brocade's '427 Patent and the '370 Patent are related and share a common specification. Both patents are titled "Redundancy Support for Network Address Translation." The '427 Patent 9 application was filed on October 18, 2002, and the patent issued on January 12, 2010. The '370 10 2007, and the patent issued on May 11, 2010.

Brocade's '195 Patent, titled "System and Method for Providing Network Route Redundancy Across Layer 2 Devices," is unrelated to any of the patents-in-suit. Its application 14 was filed April 2, 2007, and the patent issued on July 7, 2009.

Patent is a divisional of the '427 Patent. The '370 Patent application was filed on January 24,

Brocade's '500, '009, '629, '301, and '678 Patents all relate to "Global Server Load Balancing." The application for the '500 Patent was filed on September 26, 2000, and the patent 17 issued on November 18, 2008. The '009 Patent is a continuation of the '500 Patent, and the two 18 share a common specification. The '009 Patent's application was filed on April 27, 2007, and the 19 patent issued on August 25, 2009. The '629 Patent is a continuation in part of the '009 and '500 20

Patents, and their specifications, while not identical, have much in common. The '629 Patent's 21 application was filed February 28, 2003, and the patent issued February 2, 2010. 22 23 specification. The '301 Patent's application was filed May 6, 2004, and the patent issued 24 November 23, 2010. 26

Brocade's '678 Patent is a continuation of the '301 Patent, and they share a common September 1, 2009. The '678 Patent's application was filed July 20, 2009, and the patent issued 25

The '185 Patent was filed July 20, 2009, and the patent issued November 23, 2010. A10's Taiwan affiliate, A10 Networks, Inc. Taiwan, purchased the '185 Patent from its original assignee, 28 the Industrial Technology Research Institute, on March 18, 2011. Declaration of Siddhartha M. Venkatesan in Support of Brocade's Motion for Summary Judgment of Noninfringement of U.S. 2

Patent No. 5,875,185, ECF No. 223 Ex. A. A10 acquired the '185 Patent on May 10, 2011. Id. translation (NAT) devices (such as routers or switches) in the event of a failover." '427 Patent 8

B.Background and Description of the Inventions

The inventions at issue relate to improving various aspects of network communications.

1.'427 and '370 Patents

The '427 and '370 Patents both teach "providing redundancy support for network address 1:10-12. A NAT device translates Internet Protocol (IP) addresses used within one network to a 9 different IP address known within another network. Id. at 1:15-17. For example, a company may 10 use a NAT device to map its local inside network addresses to one or more global outside IP addresses, and map the global IP addresses on incoming packets back into local IP addresses. Id. at 1:20-24. Such translation is used for security and to limit the number of IP addresses a company 13 uses to communicate outside of its local inside network. Id. at 1:24-34. 14 15 that occurred when a NAT device without redundancy failed due to, for instance, a power failure. Id. at 1:41-45; '370 Patent at 1:48-50. In such situations, without redundancy, the NAT device 17 would be unable to perform address translation and to forward traffic. See '427 Patentat 1:47-48; 18 '370 Patent at 1:52-56. Even in prior art systems that included a backup NAT device, a NAT 19 device failure would result in network downtime and lost traffic between the time that the failure 20 occurred and the time that the backup NAT device was brought online. '427 Patentat 1:48-53; 21

'370 Patent at 1:56-62. The inventions claimed by the '427 and '370 Patents provide a method for 22 redundancy support, which allows a backup NAT device to continue the NAT function of a failed 23 master NAT device without incurring downtime after the failure. See id. at 2:54-62; '370 Patent at

The inventions claimed by the '427 and '370 Patents overcome a problem in the prior art 2.'195 Patent

The '195 Patent teaches "systems and methods for providing route redundancy across Layer 2 devices, as well as selected ports on L2 devices." '195 Patent at 1:38-40. The invention solves 28 network traffic problems encountered by networks that cover large geographic areas such as Metropolitan Area Networks that span a single urban metropolitan environment. Id. at 1:52. These 2 large networks are moving towards using switches, rather than Layer 3 devices such as routers, to 3 avoid latency problems associated with the use of Layer 3 devices. Id. at 1:64-66. "In a switched 4 network, all hosts or end nodes connected to the same physical Local Area Network ("LAN") 5 segment reside in the same broadcast domain, which has the potential of flooding the network with 6 traffic and making it essentially unusable as the network grows." Id. at 1:67-2:4. The '195 Patent 7 provides route redundancy to Layer 2 networks and improves on the shortcomings of the prior art. 8

The invention achieves route redundancy by having "a plurality of switches arranged in arbitrary 9 configuration or architecture, but must remain loop free through the use, for example, of spanning 10 tree or other protocol. Redundancy is provided through use of a virtual switch identified by an address and having two or more layer switches which communicate with one another to elect a master at any given time." Id. at 3:43-49.

15 load-balancing ("GSLB") switch to achieve load balancing among servers. 16 Name System ("DNS")] query by a client, providing the address of a server that is expected to 18 serve the client with a high performance in a given application." '500 Patent at 1:7-11. When an 19 internet user seeks access to a website by typing in a Uniform Resource Locator ("URL"), a device 20 known as a DNS server translates the URL into an IP address. See id. at 1:13-17. Websites that 21 receive heavy traffic may have multiple valid IP addresses so no one IP address is overloaded with 22 requests. Brocade's Initial Claim Construction Brief ("Brocade's CC Br."), ECF No. 227, at 13. 23

The DNS server achieves "load balancing" by distributing requests across multiple IP addresses. Id. The prior art used a "round-robin algorithm to rotate the IP addresses in a list of responsive IP 25 addresses, so as to distribute equally the requests for access among the host servers." '500 Patent 26 at 1:39-43. The prior art method had certain shortcomings like, for example, not optimizing the IP 27 address for a particular request or providing a non-working IP address for a down server. Id. at 28

3.The Global Sever Load-Balancing ("GSLB") Patents

The '500, '009, '629, '301, and '678 Patents all relate generally to using a global server

The '500 and '009 Patents relate to "achieving load balancing by, in response to a [Domain 1:45-49.

2 invention, whereby a GSLB server, upon receipt of a request to resolve an IP address, ranks the 3 responsive addresses based on various performance metrics. 4 performance for the client is placed at the top of the list. Examples of suitable performance metrics include availability metrics (e.g., a server's or an application's health), load metrics (e.g., a site switch's session capacity or a corresponding preset threshold), and proximity metrics . . . . The ordered list can also be governed by other policies, such as the least selected host server.

The '500 Patent and its relatives improve upon the prior art by teaching the GSLB In one embodiment, the IP address that is estimated to provide the best expected load balancing, but adds additional metrics, such as a weighted site metric, a weighted IP metric, or an active bindings metric. See '629 Patent at 2:45-57.

The '678 and '301 Patents improved upon the prior art by allowing a single DNS server to 13 act as an authoritative DNS server for multiple domains, yet applying different criteria in 14 evaluating the "best" address for each domain. See '301 Patent at 4:22-24, 6:11-22. Before the 15 invention of the '301 Patent, there was no way to configure a GSLB switch to use different metrics 16 or rules in evaluating the "best" address for each domain. See, e.g., '301 Patent at 2:8-30. 17

A10's '185 Patent, titled "Seamless Handoff for a Wireless LAN/Wired LAN

Internetworking," claims methods of keeping a mobile device, known as a mobile terminal, 20 connected to a wireless local area network (WLAN) as it moves around and passes from one base 21 station's coverage area to another. The invention provides a method for seamlessly handing off a 22 mobile terminal from one base station to another without losing a network connection. See '185 23

"virtual channel connection" ("VCC") to connect mobile terminals within a network. See id. at 25

1:60-65. The prior art's shortcoming was that as a mobile terminal with a VCC to another mobile 26 terminal moves from one base station's coverage to another, the distance the message must travel 27 increases, which leads to bandwidth waste and slows a network down. Id. at 2:31-32; 2:54-57. 28 Id. at 4:1-14.

Like the '500 and '009 Patents, the '629 Patent performs a similar function of achieving 4.A10's '185 Patent Patent 1:5-10. The invention improves upon the prior art's "path elongation" method of using a 24 The invention is a new handoff method that maintains a mobile terminal's VCC as the mobile terminal moves from one base station's coverage to another, but reduces or eliminates path 2 elongation. Id. at 3:19-35. 3

4 a mobile terminal moves from a first base station to a second base station that is connected to the 5 same switch, and (2) "interswitch mobility," where the mobile device moves from a base station 6 associated with a first switch to a new base station associated with a second switch. Id. at 3:21-26. path elongation. Id. at 3:27-29. Under the prior art, when a mobile device moved from one base 9 station to another, data had to travel to the old base station first, back to the switch, and then to the 10 new base station. Id. at 2:31-54. Under the '185 Patent's method, the switch changes the data path 11 directly to the new base station and eliminates the path through the original base station. Id.

The invention teaches handoff methods for two scenarios: (1) "intraswitch mobility," where The invention's handoff method in the intraswitch mobility scenario completely eliminates at 3:27-29. This intraswitch handoff is achieved through four "control messages": "location 13 message," "connection message," "routing message," and "complete message." Id. at 5:50-6:4. 14

The meaning of some of these control messages is disputed by the parties, and the Court discusses 15 the disputed messages in further detail and construes their meaning below. 16 17 completely eliminate, path elongation. Id. at 2:29-35. The '185 Patent teaches a handoff method 18 where the switch performs the path set-up, rather than the original base station. Id. at 2:29-30. The 19 path may be elongated from the switch connected to the original base station, to the new base 20 station, rather than from the original base station to the new base station. Id. at 2:30-33. The 21 interswitch handoff uses the "location message," "connection message," and "routing message" 22 discussed above. Id. at 7:8-10. It also uses a "couple message," discussed in greater detail and 23 construed below, and a signaling virtual channel. Id. at 7:10-11.

"Ultimately, the interpretation to be given a term can only be determined and confirmed with a full 28 understanding of what the inventors actually invented and intended to envelop with the claim."

The invention's handoff method in the interswitch mobility scenario reduces, but does not


Claim construction is a question of law to be determined by the Court. Markman v. Westview Instruments, Inc., 52 F.3d 967, 979 (Fed. Cir. 1995) (en banc), aff'd 517 U.S. 370 (1996).

Phillips v. AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en banc) (internal quotation marks 2 omitted). Accordingly, a claim should be construed in a manner that "stays true to the claim 3 language and most naturally aligns with the patent's description of the invention." Id.

In construing disputed terms, the court looks first to the claims themselves, for "[i]t is a 'bedrock principle' of patent law that 'the claims of a patent define the invention to which the 6 patentee is entitled the right to exclude.'" Id. at 1312 (quoting Innova/Pure Water, Inc. v. Safari 7

Water Filtration Sys., Inc., 381 F.3d 1111, 1115 (Fed. Cir. 2004)). Generally, the words of a claim 8 should be given their "ordinary and customary meaning," which is "the meaning that the term[s] 9 would have to a person of ordinary skill in the art in question at the time of the invention." Id. at 10 1312-13. In some instances, the ordinary meaning to a person of skill in the art is clear, and claim construction may involve "little more than the application of the widely accepted meaning of commonly understood words." Id. at 1314. 13

14 readily apparent, and the court must look to other sources to determine the term's meaning. Id. 15

Under these circumstances, the court should consider the context in which the term is used in an 16 asserted claim or in related claims, bearing in mind that "the person of ordinary skill in the art is 17 deemed to read the claim term not only in the context of the particular claim in which the disputed 18 term appears, but in the context of the entire patent, including the specification." Id. at 1313. 19

Indeed, the specification is "'always highly relevant'" and "'[u]sually [] dispositive; it is the single 20 best guide to the meaning of a disputed term.'" Id. at 1315 (quoting Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)). Where the specification reveals that the 22 patentee has given a special definition to a claim term that differs from the meaning it would 23 ordinarily possess, the inventor's lexicography governs. Id. at 1316. Likewise, where the 24 specification reveals an intentional disclaimer or disavowal of claim scope by the inventor, the 25 inventor's intention as revealed through the specification is dispositive. Id. 26 27 complete record of proceedings before the PTO and includes the cited prior art references. The In many cases, however, the meaning of a term to a person skilled in the art will not be

The Court may also consider the patent's prosecution history, which consists of the Court may consider prosecution history where it is available in evidence, for the prosecution history "can often inform the meaning of the claim language by demonstrating how the inventor 2 understood the invention and whether the inventor limited the invention in the course of 3 prosecution, making the claim scope narrower than it otherwise would be." Id. at 1317 (internal 4 citations omitted). 5

Finally, the court is also authorized to consider extrinsic evidence in construing claims,

6 such as "expert and inventor testimony, dictionaries, and learned treatises." Markman, 52 F.3d at 7

980 (internal citations omitted). Expert testimony may be particularly useful in "[providing] 8 background on the technology at issue, [explaining] how an invention works, [ensuring] that the 9 court's understanding of the technical aspects of the patent is consistent with that of a person of 10 skill in the art, or [establishing] that a particular term in the patent or the prior art has a particular meaning in the pertinent field." Phillips, 415 F.3d at 1318. Although the court may consider evidence extrinsic to the patent and prosecution history, such evidence is considered "less 13 significant than the intrinsic record" and "less reliable than the patent and its prosecution history in 14 determining how to read claim terms." Id. at 1317-18 (internal quotation marks and citation 15 omitted). Thus, while extrinsic evidence may be useful in claim construction, ultimately "it is 16 unlikely to result in a reliable interpretation of patent claim scope unless considered in the context 17 of the intrinsic evidence." Id. at 1319. Any expert testimony "'that is clearly at odds with the 18 claim construction mandated by the claims themselves, the written description, and the prosecution 19 history" will be significantly discounted. Id. at 1318. 20


A."base address corresponding to . . . pool of . . . addresses"

Brocade's Proposed Construction A10's Proposed Construction Plain and ordinary meaning.*fn1 "starting address of . . . pool of . . . addresses"

The terms "base address corresponding to . . . pool of addresses" appear in Claims 1, 6, and 8 of the '427 Patent, and Claims 1, 6, 10, 18, and 27 of the '370 Patent. For example, Claim 1 of 3 the '427 Patent recites: 4 a storage medium having instructions stored thereon that are executable by a back-up device to: share, by said back-up device with a master device, a base address corresponding to a first pool of first addresses that are owned by said master device; perform network address translation (NAT) and routing, by said back-up device, for a second pool of second addresses while said master device is active; detect, by said back-up device, a failure of said master device; and assert ownership, by said back-up device, of all of said first addresses of said first pool corresponding to said base address, in response to detection by said back-up device of said failure.

'427 Patent at 9:11-26 (emphasis added).

The Court finds it unnecessary to construe "corresponding to" to mean "of," as A10

15 proposes, because the term "corresponding to" would be well understood by a jury and does not 16 require construction. Liquid Dynamics Corp. v. Vaughan Co., 355 F.3d 1361, 1368 (Fed. Cir. 17

2004). Furthermore, the parties do not dispute the meaning of "pool of . . . addresses." At issue, 18 therefore, is whether the term "base address" in the claims should be limited to a "starting address," 19 as it is in the specification. 20

21 address" need not be a "starting address," and that A10 is improperly attempting to import 22 limitations from specific embodiments in the specification. A10 argues that the meaning of "base 23

1. An article of manufacture, comprising:

Brocade argues that a person of ordinary skill in the art*fn2 would understand that a "base address" is not clear and that the specification dictates that the base address must be the starting 2 address, i.e. the lowest numbered address, in a pool of addresses. The Court agrees with Brocade. 5 themselves are silent as to whether a "base address" corresponding to a pool of addresses must be 6 the "starting address" of such a pool. Thus, the Court turns to the specification for further 7 guidance.

10 identify an address pool. Brocade's CC Br. 6.

1.Claim Language

As the above exemplar from the claim language shows, and Brocade points out, the claims


Brocade argues that the specification makes clear that the base address is simply used to

Brocade argues that A10's proposed construction is contrary to the intrinsic evidence. In support of this argument, Brocade points out that the word "'start' and its variations do not appear 13 anywhere in the Patents." Id. at 7. The Court notes that while the word "start" does not appear in 14 the specification in the context of base addresses, "starts" and "starting" appear in other, irrelevant 15 contexts.*fn3 Brocade also points to language that suggests that the "base address" is simply used to 16 identify the address in an address pool: "For instance, if there is a pool of NAT addresses, the base 17 address is associated to a back-up NAT ...

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