Radware, Ltd.v.F5 Networks, Inc.

Case No. 5:13-cv-02024-RMW (N.D. Cal. Nov. 6, 2015)

Case No. 5:13-cv-02024-RMW


RADWARE, LTD., et al., Plaintiffs and Counterclaim Defendants, v. F5 NETWORKS, INC., Defendant and Counterclaim Plaintiff.



F5 Networks, Inc. alleges infringement of U.S. Patent Nos. 6,437,802 ("'802 patent"); 7,831,712 ("'712 patent"); 8,103,770 ("'770 patent"); and 8,392,563 ("'563 patent") against plaintiffs and counterclaim-defendants Radware, Inc. and Radware Ltd. On August 10, 2015, Radware filed a motion for summary judgment of non-infringement of the F5 patents. Dkt. No. 240. F5 opposed the motion, and Radware replied. Dkt. Nos. 244, 248-2. F5 then filed a motion for leave to file a surreply. Dkt. No. 250, 251. F5's motion for leave to file a surreply is granted. For the reasons set forth below, Radware's motion for summary judgment is denied.


The F5 asserted patents relate to load balancing between servers on a network. An HTTP cookie is used "for the purpose of persistently directing HTTP connections to the same destination." '802 patent, col.5, ll.46-47. Many data transmissions use HTTP, an application level protocol for transferring resources across the Internet. '802 patent col.5 ll.52-54. A server, when returning a web page or other HTTP object to a client, may also send a piece of "state" information that the client's web browser may store. Id. col.6 ll.1-3. This state object is called a "cookie," for no compelling reason. Id. col.6 ll.8-9. A cookie may be used, for example, to send back registration information so that a user does not have to retype a user ID number or indicate specific preferences each time the user connects to a website or service. Id. col.6 ll.10-18.

F5 alleges that Radware infringes claims 33, 42, 43, and 51 the '802 patent; claims 1, 5-7, 10, 12, and 14-25 of the '712 patent; claims 1, 4, 6, 7, and 9-13 of the'770 patent; and claims 1-3, 5-6, 17-19, and 21-22 the '563 patent. --------

To meet user demand, some content providers host copies of content and applications on multiple servers. A device such as a "server array controller," in the language of F5's patents, might then balance the load among the servers. See '802 patent col.l ll.26-34. In some cases, however, the saved state of the relationship between a client and server may create a load balancing problem. Id. col.6 ll.39-41. For example, each server that is managed by a server array controller may not share the same state relationship with a given client. Id. col.6 ll.41-44. In that case, the controller must persistently send a repeated client HTTP request to the same node server because it is difficult to recreate the same state relationship in another server during the HTTP request/response session. Id. col.6 ll.44-47. The claimed inventions allow a network device to balance load and route clients to the proper server based on information in a cookie.

All four F5 patents share substantially the same specification, and the specifications disclose four distinct modes of operation—associative, passive, insert, and rewrite. These four modes are significant because the parties agree that Radware is licensed to practice two of the four modes described in the patent specifications—the associative mode and the passive mode. See Dkt. No. 240 at 3; Dkt. No. 244 at 4-5. F5 asserts infringement of the unlicensed insert and rewrite modes. Dkt. No. 51-1 at 4-5.

In associative mode, illustrated in Figures 3A and 3B of the asserted patents, the server array controller inserts a cookie with information uniquely identifying the client into the HTTP response's header. '802 patent col.9 ll.39-42. Alternatively, the selected node server may include a cookie command in the HTTP response's header that contains blank information, after which the server array controller will rewrite this blank information with information that uniquely identifies the client. Id. col.9 ll.44-49. The server array controller maps the identified client and the address of the selected node server into a table that is stored in the memory of the controller. Id. col.9 ll.50-53. The other modes do not employ a mapping table that maps client identifiers to selected servers.

Unlike the associative mode, the passive, rewrite, and insert modes generate cookies containing server identifiers, not client identifiers. In passive mode, illustrated in Figures 4A and 4B of the asserted patents, the selected node server generates an HTTP response that includes cookie information identifying the selected node server. Id. col. 10 ll.59-62. The server array controller provides this HTTP response to the client. Id. col.10 ll.65-66. In rewrite mode, illustrated in Figures 5A and 5B of the asserted patents, the selected node server generates an HTTP response that includes a cookie with a blank field without information identifying the selected node server. Id. col.11 ll.55-59. The server array controller then rewrites the blank cookie information to identify the node server and passes the HTTP response with the rewritten cookie information to the client. Id. col.11 ll.61-66. In insert mode, illustrated in Figures 6A and 6B of the asserted patents, the selected node server does not write a cookie. Instead, after the node server provides an HTTP response to the server array controller, the server array controller inserts cookie information identifying the selected node server into the HTTP response and passes it to the client. Id. col.12 l.60-col.13 l.4. In the insert mode, all of the load for inserting and examining cookie information and rewriting data packets is placed on the server array controller, and none is placed on the node servers. Id. col.13 ll.39-43.








For these reasons, the court denies Radware's motion for summary judgment of noninfringement.

The court has filed an unredacted copy of this order under seal. If a party believes that any portion discloses confidential information, it must file a version of the order with the proposed redaction and provide a declaration setting forth the bases for asserting confidentiality. The declaration and proposed redactions may be filed under seal. The court will evaluate any such confidentiality contention and make a decision whether to approve the proposed redaction or to remove it, thus rendering the underlying content public. Any proposed redactions and declarations in support must be filed by November 20, 2015.

IT IS SO ORDERED. Dated: November 6, 2015


Ronald M. Whyte

United States District Judge