Prior art

To identify the most relevant prior art for US patent 10735488, I will consult the "References Cited" section of the patent as available on Google Patents.

Upon reviewing US10735488 on Google Patents (https://patents.google.com/patent/US10735488/en), the "References Cited" section lists the following U.S. Patent Documents:

U.S. Patent Documents Cited:

1. US6185619B1

   • Full Citation: US6185619B1 (Schoen et al.)
   • Publication/Filing Date: Publication: Feb 6, 2001
   • Brief Description: This patent describes a client-server media communication system that streams media content. It includes a stream manager that communicates with clients, and stream servers that transmit media. The system manages the delivery of media to clients and tracks client buffer levels to adjust transmission rates. It also discusses switching between servers or media streams dynamically.
   • Potential Anticipation (35 U.S.C. § 102): US6185619B1 appears to potentially anticipate elements of claims 1 and 2 of US10735488, particularly regarding the client-server interaction for media delivery and the dynamic management of streams. For example, it discloses a client receiving media from servers and managing buffer levels, which could be related to the "downloading segments" and "rendering" aspects. The concept of switching between servers for media delivery, even if for different reasons (e.g., bandwidth management), could be seen to anticipate the "selecting a second content server to replace the first content server in serving the requested digital content" feature. However, US6185619B1's explicit focus on "service level statistics" for server selection and imperceptible replacement as defined in US10735488's claims would require a detailed claim-by-claim comparison.

2. US6857022B1

   • Full Citation: US6857022B1 (Berman et al.)
   • Publication/Filing Date: Publication: Feb 15, 2005
   • Brief Description: This patent describes a system and method for dynamic network bandwidth allocation and content delivery for a client. It involves a client requesting content from a server, and the server determining an optimal bandwidth to use for delivery based on network conditions and client capabilities. The system can adjust the bandwidth during delivery.
   • Potential Anticipation (35 U.S.C. § 102): US6857022B1 could potentially anticipate aspects of claims 1 and 2 related to optimizing content delivery based on network conditions. The concept of dynamically adjusting bandwidth or content delivery based on network performance could be considered analogous to tracking "service level statistics" and making adjustments. However, it does not explicitly disclose switching between different content servers due to degradation in service from a first server, as claimed in US10735488. Its primary focus is on bandwidth allocation from a single server or source.

3. US7003567B2

   • Full Citation: US7003567B2 (Jang et al.)
   • Publication/Filing Date: Publication: Feb 21, 2006
   • Brief Description: This patent describes a method for providing multimedia streaming services, particularly for mobile terminals. It includes a content server that stores multimedia data, a streaming server that transmits the data, and a client terminal. It discusses adaptive streaming where the quality of the stream can be adjusted based on network conditions.
   • Potential Anticipation (35 U.S.C. § 102): US7003567B2, like US6857022B1, focuses on adaptive streaming and adjusting stream quality based on network conditions. While this relates to optimizing service, it doesn't directly disclose the method of "downloading a list of content servers," "tracking service level statistics for the content servers in the list," and "selecting a second content server to replace the first content server" in the event of degradation, which are key elements of US10735488's independent claims.

4. US7028096B1

   • Full Citation: US7028096B1 (McCue)
   • Publication/Filing Date: Publication: Apr 11, 2006
   • Brief Description: This patent describes a system and method for transmitting digital audio data by segmenting an audio stream into small digital audio files using natural language gaps. It also introduces a virtual audio stream descriptor to manage and track these segments. This reference focuses on the segmentation and tracking aspects of audio delivery.
   • Potential Anticipation (35 U.S.C. § 102): This patent (US7028096B1) is highly relevant as it shares an inventor (McCue) with US10735488 and describes the foundational concept of segmenting audio streams into small files and using a virtual descriptor. This reference primarily anticipates the type of content being delivered (segmented audio files) and the management of those files (virtual audio stream descriptor) as part of the broader system. However, US10735488's independent claims 1 and 2 specifically focus on the server selection and switching mechanism based on service level statistics to ensure continuous, imperceptible content delivery, which is distinct from the core segmentation and tracking described in US7028096B1. Therefore, while US7028096B1 lays groundwork for the content handling, it does not explicitly detail the multi-server performance management system of US10735488's claims.

5. US20030018783A1

   • Full Citation: US20030018783A1 (Schoen et al.)
   • Publication/Filing Date: Publication: Jan 23, 2003
   • Brief Description: This published application describes methods and systems for distributing streaming media, including the use of a content delivery network (CDN) to deliver media from multiple servers. It discusses dynamically determining the optimal server for a client based on various factors, including network latency and server load, to improve streaming performance.
   • Potential Anticipation (35 U.S.C. § 102): This reference is very strong prior art. It explicitly discloses "distributing streaming media" using "multiple servers" and "dynamically determining the optimal server for a client" based on "network latency and server load," which directly correlates to "tracking service level statistics for the content servers" and "selecting a first content server" as per US10735488's claims. Furthermore, the concept of a CDN inherently involves switching between servers to maintain performance. The imperceptible nature of server replacement could be an inherent goal or outcome of such dynamic server selection in a CDN. This reference potentially anticipates many elements of independent claims 1 and 2, particularly the core idea of client-side server selection and switching based on performance metrics from a list of available servers.

Summary of Most Relevant Prior Art:

• US20030018783A1 (Schoen et al.) appears to be the most relevant prior art. Its disclosure of dynamically selecting optimal servers from a network of content delivery servers based on performance metrics (like network latency and server load) directly addresses the core innovation of US10735488's independent claims, namely downloading a list of servers, tracking service level statistics, and selecting a server based on those statistics, and by implication, switching between them to maintain service.
• US6185619B1 (Schoen et al.) is also highly relevant due to its discussion of client-server media communication, stream management, and dynamic switching between servers or media streams.
• US7028096B1 (McCue) is relevant for establishing the segmented audio content and virtual descriptor, which forms the underlying data structure that US10735488's server management system operates on. However, its focus is not on the multi-server load balancing aspect.

A thorough anticipation analysis would require a detailed element-by-element comparison of the claims of US10735488 against the disclosures of these prior art documents. However, based on the provided brief descriptions, US20030018783A1 seems to cover the most critical aspects of server selection and switching based on performance for content delivery.