Opinion ID: 3154932
Heading Depth: 3
Heading Rank: 2

Heading: “[A]n optimal server”

Text: The second remaining dispute is whether “an optimal server” is necessarily limited to a single “best” server, or can refer to several potentially optimal servers from which content is retrieved. The phrase “optimal server” does not appear in the patent. Instead, it is nested within the parties’ stipulated claim constructions as follows. “Tagging” was stipulated to mean “providing a ‘pointer’ or ‘hook’ so that the object resolves to a domain other than the content provider domain.” The phrase “to resolve to a domain other than the content provider domain” was stipulated to mean “to specify a particular group of computers that does not include the content provider from which an optimal server is to be selected.” Substituting the stipulated constructions into claim 19 results in the following, with emphasis added: 19 [substituted]. A content delivery service, comprising . . . . for a given page normally served from the content provider domain, providing a ‘pointer’ or ‘hook’ to embedded objects on the page so that requests for those objects specify a particular group of computers that does not include the content provider from which an opti- mal server is to be selected .... 14 AKAMAI TECHNOLOGIES, INC. v. LIMELIGHT NETWORKS, INC. serving at least one embedded object of the given page from a given content server in the domain instead of from the content provider domain. During the Markman hearing, the parties disputed the meaning of “an optimal server.” The district court construed claim 19 to require “the content delivery system to serve an embedded object from one or more content servers which are ‘[m]ost favorable or desirable,’ that is, servers which meet some or all of the criteria described in the specification.” In the jury instruction, the district court elaborated on the criteria, explaining that “an optimal server” was: “one or more content servers that are better than other possible choices considering some or all of the following criteria: (1) being close to end users; (2) not overloaded; (3) tailored to viewers in a particular location; (4) most likely to already have a current version of the required file; and (5) depend[e]nt on network conditions.” Limelight argues that: 1) the unambiguous meaning of “optimal” is necessarily restricted to a single aggregate “best” server; 2) the court’s ambiguous construction improperly left a claim construction issue for the jury; and 3) Akamai is judicially estopped from arguing that “optimal” does not require a single “best” server by its statements equating “optimal” to “best.” Limelight’s arguments are unconvincing. First, Limelight fails to appreciate the context of the selection of “an optimal server” in the claim. The selection of “an optimal server” describes the functionality enabled by the necessary “tagging.” In other words, the embedded objects are tagged such that a group of computers is identified, and from which an optimal server is chosen. The ’703 patent is replete with examples in which conditions or circumstances independent of the tag influence which server ultimately serves the embedded object. The tagging AKAMAI TECHNOLOGIES, INC. v. LIMELIGHT NETWORKS, INC. 15 described in the ’703 patent thus allows for the tag to ultimately lead to service from more than a single possible server. When the browser makes a request for an object, then the software on the ghost does the following: “If a copy of the file is already stored on the ghost, then the data is returned immediately. If, however, no copy of the data on the ghost exists, a copy is retrieved from the original server or another ghost server.” ’703 patent, col.12, ll.31-35. Similarly, the specification explains that the tagging allows “a ghost server [to] redirect the user to a closer server (or to another virtual address that is likely to be resolved to a server that is closer to the client).” Id. at col.12, ll.44-47. And again, “[p]erformance for long downloads can also be improved by dynamically changing the server to which a client is connected based on changing network conditions.” Id. at col.12, ll.53-55. These examples undermine Limelight’s position in two ways. First, the tagging of the embedded objects provides the capability to select a server, and then select a different server – in other words, tagging enables the selection of one of several servers. Second, the criteria for server selection are not aggregated during tagging, wherein the system only allows serving from the single server that is the “winner” of the aggregated criteria. Instead, in one instance, a server may be chosen because it is closest to the user; in another instance, because another server does not have the file; and in yet another instance, because of overload of the server or network conditions. Choosing based on any of these criteria is indicated as a capability of the claimed tagging system – not merely choosing a single “aggregate best” server. Nothing in the patent limits the functionality of the tag to selecting an “aggregate best” – indeed, which criteria is ultimately decisive is not a function of the tag, but occurs while the objects are served. This reading is confirmed by dependent claims 21 and 22, which further limit the serving step in claim 19 to 16 AKAMAI TECHNOLOGIES, INC. v. LIMELIGHT NETWORKS, INC. “resolving a request to the domain as a function of a requesting user’s location,” ’703 patent, cl. 21, or “resolving a request to the domain as a function of a requesting user’s location and then-current Internet traffic conditions,” id. at cl. 22. In other words, determining the ultimate server from which the embedded object will be served using one particular criteria, or two criteria. Nothing in the specification or the claims implies that these two functionalities would necessarily return the aggregate best server, or that the two rules would return the same server. Limelight argues that this identification of “one or more content servers” is an additional step identifying the list of all possible content servers from which the optimum server is selected. Limelight Supp. Opening Br. at 4. Limelight ignores that claim 20 is limiting “the serving step,” which occurs after the tagging step. Limelight’s argument that the “unambiguous” meaning of “optimal” is a single “best” is also unconvincing. As discussed above, the intrinsic evidence supports the district court’s construction. Moreover, neither the plain meaning of “optimal” nor the plain meaning of “best” is as limited as Limelight suggests to an “aggregate best” or “aggregate optimal.” The district court’s construction did not improperly leave a claim construction issue for the jury by not construing a disputed term. The district court construed optimal server during the Markman hearing as described above, and elaborated during jury instructions that “an optimal server” was: “one or more content servers that are better than other possible choices considering some or all of the following criteria: (1) being close to end users; (2) not overloaded; (3) tailored to viewers in a particular location; (4) most likely to already have a current version of the required file; and (5) depend[e]nt on network conditions.” Nothing in the construction or the jury instructions requires the jury to construe the term. Limelight AKAMAI TECHNOLOGIES, INC. v. LIMELIGHT NETWORKS, INC. 17 merely disagrees with the construction the district court adopted. Finally, Akamai’s use of “optimal” and “best” in the prior litigation does not estop Akamai from arguing that “optimal” allows for serving from other than a single composite best server because the point at issue in the discussions cited was distinct from the issue here. Limelight points to a colloquy wherein the district court questioned Akamai’s counsel about the functionality and sequencing of the tagging step, and Akamai’s counsel stated: “at some time during the serving of that object, picking the best computer to serve that object, that’s during the serving step, identifying the best computer,” and also agreed with the district court’s categorization that the process “is two steps. It tags to find the best domain and then also identifies the best computer or server within that domain.” Limelight’s reliance on this colloquy is misplaced. The discussion in that case was about the role of tagging, and Akamai’s attorney explained that the timing of the tagging step occurs with the selection of a domain, but that the selection of the “best computer” occurs during the object serving step. The issue of whether tagging enables serving from only a single “optimal server” or from a server which performs better than others within a particular criteria was never addressed. For these reasons, there is no error in the district court’s construction of “an optimal server,” nor in the jury instruction.