Obviousness

An analysis of the obviousness of US Patent 11,589,142 under 35 U.S.C. § 103, based on the prior art cited in the patent document, is as follows.

Person Having Ordinary Skill in the Art (PHOSITA)

A person having ordinary skill in the art (PHOSITA) at the time of the invention (priority date August 2, 2012) would have had a Bachelor's degree in Electrical Engineering, Computer Science, or a related field, along with several years of experience in the design and implementation of telecommunication networks. This experience would include familiarity with network routing protocols, Layer 2 and Layer 3 VPN technologies, and optical networking architectures, specifically Passive Optical Networks (PON).

Obviousness of Independent Claims 5 and 8

Claims 5 and 8 are rendered obvious by the combination of US 2008/0212598 A1 ("'598 publication") and US 2007/0092249 A1 ("'249 publication").

Claims 5 and 8 describe a method where a PON Optical Line Terminal (OLT) receives one or more data streams that have been virtually separated for a specific end-user using Virtual Routing and Forwarding (VRF). The OLT then aggregates these streams into a common data feed, which is broadcast over the PON via optical splitters to multiple Optical Network Units (ONUs). The intended ONU then extracts the private data stream for its user.

1. US 2007/0092249 A1 ('249 publication) teaches a conventional PON system architecture. It discloses a system for distributing traffic in an optical network comprising a central office apparatus (an OLT), a plurality of subscriber units (ONUs), and a passive optical distribution network with splitters connecting the OLT to the ONUs. This reference establishes the foundational shared network environment over which the claimed method operates. It describes broadcasting aggregated data downstream from the OLT to all ONUs.

2. US 2008/0212598 A1 ('598 publication) teaches a method for "Transparent Virtual Routing." This reference addresses the need to provide logically isolated network services to multiple customers over a shared physical infrastructure. It discloses a virtual router that maintains "separate and distinct routing and forwarding tables for each customer," allowing customer networks to use overlapping IP addresses without conflict. This is the core concept of Virtual Routing and Forwarding (VRF). The '598 publication explicitly teaches generating virtually separated data streams for different users at a central network location.

Motivation to Combine:

A PHOSITA would have been motivated to combine the teachings of these references to achieve a predictable and commercially desirable result. The '249 publication provides a cost-effective and high-bandwidth physical infrastructure (PON) for serving multiple users. However, the broadcast nature of a PON presents a security and network management challenge when serving distinct customers (e.g., different tenants in a building) who require private, isolated networks.

The '598 publication provides a direct solution to this problem by teaching the use of virtual routing (VRF) to create logically separate networks. A PHOSITA tasked with providing secure, multi-tenant service over a PON would have found it obvious to apply the virtual routing technique of '598 to the head-end router of the PON system described in '249. This combination would allow a service provider to use a single physical PON infrastructure to offer logically separate, secure LAN services to multiple distinct customers, with a reasonable expectation of success. The combination directly teaches receiving a VRF-separated data stream at the OLT ('598) and distributing it across the PON ('249) for extraction by the appropriate ONU, as recited in claims 5 and 8.

Obviousness of Independent Claim 1

Claim 1 is rendered obvious by the combination of US 2008/0212598 A1 ("'598 publication") and US 2007/0092249 A1 ("'249 publication"), further in view of US 6,693,878 B1 ("'878 patent").

Claim 1 adds further limitations to the methods of claims 5 and 8, notably the use of a primary and secondary router and the specific use of Multi-Protocol Label Switching (MPLS) to label the IP packages within the virtually separated data stream.

1. '598 in view of '249: As established above, this combination teaches the fundamental system of using VRF to create virtually separated data streams for different users and transmitting them over a shared PON architecture.

2. US 6,693,878 B1 ('878 patent): This patent teaches a technique for implementing Virtual Private Networks (VPNs). Crucially, it discusses the use of MPLS as a mechanism for forwarding VPN traffic across a provider's core network. The '878 patent describes associating VPN identifiers with packets and using label switching (the "LS" in MPLS) to route them, which is a foundational technique for creating scalable "MPLS VPNs."

Motivation to Combine:

By 2012, the combination of VRF and MPLS was the de-facto industry standard for creating scalable Layer 3 VPNs. A PHOSITA, having decided to use VRF to separate customer traffic as taught by '598, would have immediately considered standard methods for forwarding that traffic across the network. MPLS, as taught by the '878 patent, is not merely an alternative but a complementary and widely adopted technology used in conjunction with VRF.

The motivation to add the teaching of '878 would have been to implement the VRF-based separation in a robust, scalable, and efficient manner. Using MPLS to label and switch the VRF-separated packets between the primary and secondary routers (a common architecture for network core and edge functions) would have been an obvious and standard design choice for a network engineer building a multi-tenant service. This combination would achieve the predictable result of a well-architected, secure multi-tenant network. Therefore, adding the MPLS labeling step to the combined teachings of '598 and '249 would have been obvious to a PHOSITA.