US 8780887

US Patent 8780887, titled "Method of network-based communication in virtual network environment," was filed on September 16, 2011, and issued on July 15, 2014. The patent is assigned to Electronics and Telecommunications Research Institute ETRI, and the inventors are Sun Cheul Kim, Seong Moon, Seungwoo Hong, Ho Sun Yoon, and Ho Yong Ryu.

Abstract:
The patent describes a communication method within a virtual network environment involving a first virtual tunnel router and a second virtual tunnel router. These routers request virtual network prefix information from a tunnel mapping controller. The controller generates and transmits this information, along with a list of adjacent virtual tunnel routers. Subsequently, the virtual tunnel routers establish a tunnel, and by linking the received virtual network prefix information, they can perform direct communication.

Independent Claims Overview:

• Independent Claim 1: This claim describes a method for achieving end-to-end communication in a virtual network. It involves two or more virtual tunnel routers (a first and a second). The first virtual tunnel router receives virtual network prefix information from a tunnel mapping controller. It then checks if it has received a "hole punching" message from the second virtual tunnel router. If such a message is received, the first virtual tunnel router establishes a tunnel with the second virtual tunnel router based on the virtual network prefix information and proceeds to perform direct communication through this established tunnel.

• Independent Claim 6: This claim outlines a communication method enabling direct communication between multiple virtual tunnel routers (e.g., a first and a second) by cooperating with a tunnel mapping controller. The method includes the virtual tunnel routers requesting virtual network prefix information from the controller. The tunnel mapping controller then generates and transmits this information to each router, also providing a list of virtual tunnel routers for which previous connection information has been stored. The first and second virtual tunnel routers then create a tunnel. Finally, direct communication is performed by linking the virtual network prefix information received by each virtual tunnel router to its respective tunnel.

CAFC 2026 Dockets:
A search of the U.S. Court of Appeals for the Federal Circuit (CAFC) 2026 dockets for patent number US8780887 did not yield any explicit results indicating ongoing litigation for this specific patent within the scheduled cases for May or June 2026. General information on how to access case records before March 1, 2012, or search for documents not available through PACER was found, but no direct mention of US8780887 in current dockets.

US patent 8780887 is involved in the following known litigation:

1. District Court Case

   • Plaintiff(s): OptimNet LLC
   • Defendant(s): Cisco Systems, Inc.
   • Jurisdiction: Eastern District of Texas (E.D. Tex.)
   • Case Number: 2:25-cv-00935
   • Filing Date: September 4, 2025
   • Outcome or Current Status: Pending

2. PTAB Inter Partes Review (IPR) Case

   • Petitioner: Cisco Systems Inc.
   • Patent Owner: Optimnet LLC / Optinet LLC
   • Jurisdiction: Patent Trial and Appeal Board (PTAB)
   • Case Number: IPR2026-00320
   • Filing Date: March 27, 2026
   • Outcome or Current Status: Pending

Proceedings overview

There is currently one active AIA trial proceeding on US Patent 8,780,887, which is a pending Inter Partes Review. This means the defensive posture for a defendant is one of uncertainty, as the validity of the patent's claims is currently being challenged.

IPR2026-00320 — Cisco Systems, Inc. v. Electronics and Telecommunications Research Institute ETRI

• Type: Inter Partes Review
• Filed: 2026-03-27
• Status: Pending - The proceeding is active and has not yet reached a final disposition.
• Judge panel: Not yet publicly available.
• Petition grounds: Not yet publicly available.
• Institution decision: Not yet available. The institution decision deadline has not passed.
• Final Written Decision (if issued): Not yet issued.
• Settlement / termination: No settlement or termination information is available.
• Appeal: No appeal information is available, as a Final Written Decision has not been issued.
• Defensive value: This active IPR indicates that the patent's claims are currently under scrutiny. The outcome of this proceeding will significantly impact the defensive value. If claims are invalidated, it could weaken any assertion based on those claims. Conversely, if the claims are upheld, it could strengthen the patent owner's position.

Strategic summary

As of today, US Patent 8,780,887 has one pending IPR proceeding, IPR2026-00320, filed by Cisco Systems, Inc. The status is "Pending," meaning no claims have been definitively canceled, sustained, or otherwise decided by the PTAB. All claims of the patent are currently considered untested in the context of an AIA trial, as the institution decision and any subsequent Final Written Decision are yet to occur.

The estoppel landscape is not yet fully formed. Should IPR2026-00320 proceed to a Final Written Decision, Cisco Systems, Inc. (and its privies) would be estopped under § 315(e)(2) from raising any ground they raised or reasonably could have raised in that IPR against the claims that survive. For other potential defendants, the prior-art grounds challenged in this IPR, once made public, may still be available unless they are in privy with Cisco.

There are no apparent pattern signals of multiple IPRs by the same petitioner or aggressive PTAB appeals by the patent owner at this early stage. The petitioner, Cisco Systems, Inc., is a significant operating company often involved in patent litigation, suggesting a potentially strong interest in challenging the patent's validity.

Recommended next steps

• For any defendant currently facing assertion of US Patent 8,780,887, it is crucial to closely monitor the progress of IPR2026-00320. Key upcoming milestones include the institution decision. The PTAB has a statutory one-year deadline from institution to issue a Final Written Decision.
• The current status (Pending) means no definitive claim-level outcomes are available yet. The petition and the patent owner's preliminary response will provide insight into which specific claims are being challenged and on what grounds.
• Consulting the public docket for IPR2026-00320 on the USPTO PTAB E2E system will provide the most up-to-date information, including the institution decision and, eventually, the Final Written Decision if the case proceeds.

Inventors

• Sun Cheul Kim (Electronics and Telecommunications Research Institute ETRI)
• Seong Moon (Electronics and Telecommunications Research Institute ETRI)
• Seungwoo Hong (Electronics and Telecommunications Research Institute ETRI)
• Ho Sun Yoon (Electronics and Telecommunications Research Institute ETRI)
• Ho Yong Ryu (Electronics and Telecommunications Research Institute ETRI)

No unusual patterns detected. All inventors appear to have been employed by the original assignee at the time of filing.

Original assignee

Electronics and Telecommunications Research Institute (ETRI).

ETRI is a government-funded research institute in South Korea, focusing on R&D in information and communication technologies. While they primarily engage in research and do not "ship products" in the commercial sense, they develop technologies that are licensed and incorporated into products by other companies. Their primary line of business is R&D in telecommunications and IT. ETRI is currently an operating government-funded research institute.

Assignment timeline

• 2011-08-11 (executed) / recorded 2011-09-20 — Reel 026935/0450
  • Conveyance: Assignment
  • Assignor: Kim, Sun Cheul; Moon, Seong; Hong, Seungwoo; Yoon, Ho Sun; Ryu, Ho Yong (all inventors)
  • Assignee: Electronics and Telecommunications Research Institute
  • Correspondent: BAE, KIM & LEE IP GROUP, 11th Fl. Gangnam-daero 372, Gangnam-gu, Seoul, 135-934, Republic of Korea
  • Context: Original assignment from inventors to employer

The USPTO Assignment Center shows no further recorded assignments for US8780887 as of May 29, 2026.

Timeline diagram

timeline
    title Ownership of US 8780887
    2011 : Inventors assigned to ETRI
    2014 : Patent issued to ETRI

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The only assignment on record is from the individual inventors to their employer, ETRI, a government-funded research institute.
2. Known asserter in the chain — not present. ETRI is not a known NPE.
3. Repeat correspondent across the chain — not present. There is only one assignment recorded, so no recurrence can be observed. The correspondent for the initial assignment is BAE, KIM & LEE IP GROUP.
4. Cascading transfers — not present. Only one assignment is on record.
5. Pre-litigation transfer — unclear. While there is litigation listed for this patent on Google Patents (a US case filed in Texas Eastern District Court and a PTAB case), without a more precise date for the initial filing of the litigation, it is unclear if the single assignment from inventors to ETRI was pre-litigation. However, this initial assignment is standard practice for patents originating from employees.
6. Bankruptcy fire-sale — not present. No indication of bankruptcy for ETRI.
7. Privateering — not present. No evidence to suggest ETRI is engaging in privateering.
8. Defensive aggregator (anti-NPE) — not present. The patent is currently assigned to ETRI, not a defensive aggregator.

Verdict

Insufficient data. While the single assignment from the inventors to ETRI is a standard practice and does not, in itself, suggest NPE activity, the USPTO Assignment Center shows no subsequent recorded assignments. Without further assignment records, especially given the "Family has litigation" flags on Google Patents, it is impossible to definitively determine if the patent has moved into the hands of an NPE.

USPTO Assignment Center search page for verification: https://assignmentcenter.uspto.gov/

Here is an analysis of the most relevant prior art for US patent 8780887, based on the patent's own citations. The analysis includes a full citation, publication/filing date, a brief description of the reference, and a discussion of which claims it potentially anticipates under 35 U.S.C. § 102.

US8780887 Overview:
US8780887 describes a method of network-based communication in a virtual network environment, focusing on providing direct communication between virtual tunnel routers (virtual TRs) based on virtual IP addresses, especially in the presence of NATs/firewalls, and supporting mobility. Key components include a tunnel mapping controller and the use of hole punching or a tunnel relay to establish tunnels.

The core independent claims are:

• Claim 1: A method involving virtual TRs receiving virtual network prefix information, determining if a hole punching message is received, establishing a tunnel if received, and performing direct communication.
• Claim 6: A method involving virtual TRs requesting virtual network prefix information from a tunnel mapping controller, the controller generating and transmitting this information along with a list of adjacent virtual TRs, the virtual TRs creating a tunnel, and performing direct communication by linking the virtual network prefix information.

Given the focus of US8780887, the most relevant prior art will likely involve virtual networking, NAT/firewall traversal, P2P communication, tunneling, and mobility support using virtual IPs.

Identified Prior Art Citations for US8780887:

The following patent citations are listed in US8780887:

1. US20110082941A1

   • Full Citation: US20110082941A1 (en) Electronics And Telecommunications Research Institute, "Method of providing direct communication in internet protocol network"
   • Priority Date: 2009-10-06
   • Publication Date: 2011-04-07
   • Brief Description: This patent application, by the same assignee as US8780887, describes a method for providing direct communication in an IP network using a communication server and NAT traversal. It focuses on a sender terminal registering its public and private IP/port information with the communication server, the server providing this information to a receiver terminal, and then direct communication being established via hole punching if possible, or through a relay server if direct communication is not possible due to NAT/firewall types.
   • Potential Anticipation (35 U.S.C. § 102):
     • Claim 1: This reference describes a system and method for direct communication using NAT traversal (hole punching) and a central server to exchange connection information. While it deals with "terminals" rather than "virtual tunnel routers" directly, the underlying mechanism of a central entity (communication server vs. tunnel mapping controller) facilitating direct communication via hole punching (or relay) based on exchanged connection information (IP/port vs. virtual network prefix information) is very similar. The "virtual network environment" and "virtual network prefix information" are distinguishing features, but the core steps of receiving connection information, determining hole punching success, and establishing a direct communication link are present. Therefore, US20110082941A1 potentially anticipates the general concept of facilitating direct communication and hole punching, particularly the steps of determining reception of a hole punching message and establishing a tunnel.
     • Claim 6: Similar to Claim 1, this reference details a server providing connection information for direct communication, and the use of hole punching. The concept of "virtual network prefix information" and "virtual tunnel routers" are key differences. However, the steps of requesting information from a central controller, the controller providing information to enable direct communication, and creating a tunnel for direct communication are conceptually related. The explicit mention of "virtual network prefix information" and "list of virtual tunnel routers for which previous connection information has been stored" in Claim 6 presents a stronger differentiating factor compared to the general "IP and port information" of a terminal in US20110082941A1.

2. KR20080059900A

   • Full Citation: KR20080059900A (en) 한국과학기술정보연구원, "System level MPI communication method that supports private IP in grid environment through modified hole punching"
   • Priority Date: 2006-12-26
   • Publication Date: 2008-07-01
   • Brief Description: This Korean patent application describes a method for parallel processing communication (MPI) in a grid environment, enabling communication between nodes using private IP addresses through a modified hole punching technique. It aims to overcome limitations imposed by NATs and firewalls in grid computing environments by modifying how hole punching is performed.
   • Potential Anticipation (35 U.S.C. § 102):
     • Claim 1: This reference directly mentions "hole punching" to support communication with "private IP" in an environment that implies network address translation. The focus is on communication between "nodes" in a "grid environment". If "nodes" are interpreted broadly to include "virtual tunnel routers," and the "grid environment" as a form of "virtual network environment," then the core mechanism of using hole punching to enable communication (which is inherently direct once the hole is punched) is present. The "virtual network prefix information" and "tunnel mapping controller" are specific elements that would need careful comparison.
     • Claim 6: The method focuses on private IP communication using hole punching. While it enables direct communication between "nodes," the specific architecture of "virtual tunnel routers," "tunnel mapping controller," and the exchange of "virtual network prefix information" for linking to tunnels as described in Claim 6 would need detailed comparison. The presence of "hole punching" for direct communication through private IPs makes it highly relevant.

3. US20100235481A1

   • Full Citation: US20100235481A1 (en) Lantronix, Inc., "Various methods and apparatuses for accessing networked devices without accessible addresses via virtual ip addresses"
   • Priority Date: 2007-10-24
   • Publication Date: 2010-09-16
   • Brief Description: This patent application describes methods and apparatuses for accessing networked devices that do not have publicly accessible addresses (e.g., behind NATs or firewalls) by assigning them "virtual IP addresses." A central server (control server) maps these virtual IPs to the actual physical addresses, allowing communication to be routed through this server or by facilitating direct connections.
   • Potential Anticipation (35 U.S.C. § 102):
     • Claim 1: This reference is highly relevant due to its explicit use of "virtual IP addresses" to access devices behind NATs/firewalls. The "control server" functions similarly to a "tunnel mapping controller" in managing these virtual addresses and facilitating connectivity. If the "accessing networked devices" implies direct communication through tunnels (even if relayed), it could potentially anticipate the broad concept. The specific "hole punching message" step and "establishing a tunnel" between "virtual tunnel routers" would be crucial distinguishing factors, as US20100235481A1 might rely more on relaying through the central server.
     • Claim 6: The concept of "virtual network prefix information" and "virtual tunnel routers" aligns strongly with the "virtual IP addresses" and "networked devices" of this reference. The "tunnel mapping controller" generating and transmitting information (virtual network prefix information) is analogous to the control server mapping and providing virtual IP addresses. The novelty of Claim 6 would depend on the specific "creating a tunnel" mechanism (e.g., direct hole punching between VTRs vs. server-mediated access) and the "linking the virtual network prefix information received by the first virtual tunnel router and the second virtual tunnel router, respectively."

4. US8296437B2

   • Full Citation: US8296437B2 (en) Logmein, Inc., "Server-mediated setup and maintenance of peer-to-peer client computer communications"
   • Priority Date: 2005-12-29
   • Publication Date: 2012-10-23
   • Brief Description: This patent describes a system and method for establishing and maintaining peer-to-peer (P2P) communication between client computers, often located behind NATs or firewalls, using a server. The server assists in discovering network topologies, exchanging connection information, and facilitating direct connections (e.g., via UDP hole punching) or relaying communication when direct connections are not possible.
   • Potential Anticipation (35 U.S.C. § 102):
     • Claim 1: This reference directly addresses P2P communication (which US8780887's background discusses as a problem area) and explicitly mentions server-mediated setup and UDP hole punching for direct communication between clients (peers). If "client computer communications" can be analogous to "virtual tunnel routers" in their function of establishing direct communication, and the "server" to the "tunnel mapping controller," then many elements of Claim 1 are present. The "virtual network environment" and "virtual network prefix information" are key distinctions.
     • Claim 6: The "server" collecting and providing information for P2P communication, including network topology, for enabling direct connections, aligns with the role of the "tunnel mapping controller." The "creating a tunnel" step, often through hole punching, is also a feature. Again, the specific definitions of "virtual tunnel routers" and "virtual network prefix information" as distinct network identifiers within a virtual environment, rather than just public/private IP/port pairs of clients, would be critical for differentiating Claim 6.

5. US20080307519A1

   • Full Citation: US20080307519A1 (en) Avaya Technology Llc, "Peer-to-peer network over a virtual private network"
   • Priority Date: 2007-06-06
   • Publication Date: 2008-12-11
   • Brief Description: This patent application describes establishing a peer-to-peer (P2P) network over a virtual private network (VPN). It enables peers, potentially behind NATs, to communicate directly or through a relay by utilizing the VPN infrastructure. The VPN provides a secure and managed overlay network, simplifying direct communication challenges.
   • Potential Anticipation (35 U.S.C. § 102):
     • Claim 1: This reference provides P2P communication within a "virtual private network," which is a type of "virtual network environment." The P2P communication might involve establishing direct links between peers, which could be functionally similar to "virtual tunnel routers." The methods of overcoming NATs (including potential hole punching or relaying through the VPN) are also relevant. The explicit steps of "receiving a hole punching message" and "establishing a tunnel based on virtual network prefix information" would need to be directly taught or inherently present within the VPN P2P setup for full anticipation.
     • Claim 6: A "virtual private network" essentially creates a virtual network and facilitates communication between "peers" (analogous to virtual TRs). The VPN typically manages routing and addressing (functionally related to "virtual network prefix information"). The "tunnel mapping controller" could find an analogue in a VPN controller or server. However, Claim 6's emphasis on specific "virtual network prefix information" and direct tunnel creation with linking, particularly with the optional inclusion of hole punching or tunnel relay, would need to be present in detail in US20080307519A1 for direct anticipation.

Other Patent Citations:

1. US20060130136A1

   • Full Citation: US20060130136A1 (en) Vijay Devarapalli, "Method and system for providing wireless data network interworking"
   • Priority Date: 2004-12-01
   • Publication Date: 2006-06-15
   • Brief Description: This patent describes methods and systems for interworking different wireless data networks, focusing on mobility and seamless connectivity across heterogeneous networks, often involving tunneling and gateways.
   • Potential Anticipation (35 U.S.C. § 102): Less direct anticipation. While it discusses interworking and mobility (concepts in US8780887), it doesn't appear to specifically address direct communication between virtual routers in a virtual network environment using virtual IPs and NAT/firewall traversal techniques like hole punching in the same manner as US8780887's claims.

2. US7237260B2

   • Full Citation: US7237260B2 (en) Matsushita Electric Industrial Co., Ltd., "Method for dynamic selection for secure and firewall friendly communication protocols between multiple distributed modules"
   • Priority Date: 2003-07-08
   • Publication Date: 2007-06-26
   • Brief Description: This patent focuses on selecting communication protocols that are secure and firewall-friendly for communication between distributed modules, particularly in scenarios where direct communication might be restricted.
   • Potential Anticipation (35 U.S.C. § 102): Less direct anticipation. It deals with firewall traversal and communication protocols but doesn't explicitly teach the specific virtual network architecture, virtual tunnel routers, virtual network prefix information, or the hole punching/tunnel relay mechanisms of US8780887.

3. US20070174436A1

   • Full Citation: US20070174436A1 (en) Hajime Maekawa, "Communication system, information processing system, information processing apparatus, tunnel management apparatus, information processing method, tunnel management method, and program"
   • Priority Date: 2004-01-30
   • Publication Date: 2007-07-26
   • Brief Description: This reference describes a communication system that uses tunnels for communication, and a tunnel management apparatus to manage these tunnels. It aims to provide seamless communication across networks.
   • Potential Anticipation (35 U.S.C. § 102): While it involves tunneling and tunnel management (relevant to US8780887), it does not explicitly detail the "virtual tunnel routers," "virtual network prefix information," "hole punching," or "tunnel mapping controller" in the specific context of providing a direct communication environment in a virtualized network as claimed by US8780887.

4. US7609701B2

   • Full Citation: US7609701B2 (en) Zheng Yang, "Communication using private IP addresses of local networks"
   • Priority Date: 2006-02-22
   • Publication Date: 2009-10-27
   • Brief Description: This patent addresses communication between devices using private IP addresses in local networks, often involving NAT traversal techniques to enable external connectivity or communication between different private networks.
   • Potential Anticipation (35 U.S.C. § 102): Relevant due to "private IP addresses" and implicitly NAT traversal. However, it lacks the explicit architecture of "virtual tunnel routers" and "tunnel mapping controller" combined with "virtual network prefix information" in a comprehensive virtual network environment as claimed by US8780887.

5. US7843918B2

   • Full Citation: US7843918B2 (en) Cisco Technology, Inc., "Selectively forwarding traffic through tunnels in a computer network"
   • Priority Date: 2008-01-25
   • Publication Date: 2010-11-30
   • Brief Description: This patent describes methods for selectively forwarding traffic through tunnels in a computer network, allowing for flexible routing and network management.
   • Potential Anticipation (35 U.S.C. § 102): Focuses on selective traffic forwarding through tunnels. While tunneling is a core element of US8780887, this patent does not appear to teach the virtual network specific components (virtual TRs, virtual network prefixes) or the direct communication setup using hole punching/tunnel relay as claimed.

6. US8014421B2

   • Full Citation: US8014421B2 (en) Citrix Systems, Inc., "Systems and methods for adjusting the maximum transmission unit by an intermediary device"
   • Priority Date: 2004-07-23
   • Publication Date: 2011-09-06
   • Brief Description: This patent describes methods and systems for adjusting the Maximum Transmission Unit (MTU) by an intermediary device (e.g., a gateway or proxy) to optimize network performance, particularly for traffic passing through different network segments or tunnels.
   • Potential Anticipation (35 U.S.C. § 102): This patent is concerned with MTU adjustment, which is a network optimization detail, not the core architecture or direct communication methodology of US8780887. It does not appear to directly anticipate any of the key claims.

Obviousness under 35 U.S.C. § 103 requires an analysis of whether "the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains." This analysis is based on the Graham factors: (1) the scope and content of the prior art; (2) the differences between the prior art and the claims; (3) the level of ordinary skill in the pertinent art; and (4) secondary considerations of non-obviousness. While a "teaching, suggestion, or motivation" (TSM) to combine references is a factor, the Supreme Court in KSR International Co. v. Teleflex Inc. emphasized a more flexible "common sense" approach, stating that predictable results from combining familiar elements are often sufficient to prove obviousness.

The effective filing date of US 8,780,887 is October 29, 2010 (the priority date from Korean Patent Application No. 10-2010-0107107). Therefore, prior art references existing before this date are relevant.

Prior Art References (from the patent document):

• US20060130136A1 (Devarapalli): "Method and system for providing wireless data network interworking." Priority date: 2004-12-01.
• US7237260B2 (Matsushita Electric Industrial Co., Ltd.): "Method for dynamic selection for secure and firewall friendly communication protocols between multiple distributed modules." Priority date: 2003-07-08.
• US20070174436A1 (Maekawa): "Communication system, information processing system, information processing apparatus, tunnel management apparatus, information processing method, tunnel management method, and program." Priority date: 2004-01-30.
• KR20080059900A (한국과학기술정보연구원): "System level MPI communication method that supports private IP in grid environment through modified hole punching." Priority date: 2006-12-26.
• US20080307519A1 (Avaya Technology Llc): "Peer-to-peer network over a virtual private network." Priority date: 2007-06-06.
• US7609701B2 (Yang): "Communication using private IP addresses of local networks." Priority date: 2006-02-22.
• US20100235481A1 (Lantronix, Inc.): "Various methods and apparatuses for accessing networked devices without accessible addresses via virtual ip addresses." Priority date: 2007-10-24.
• US7843918B2 (Cisco Technology, Inc.): "Selectively forwarding traffic through tunnels in a computer network." Priority date: 2008-01-25.
• US20110082941A1 (Electronics And Telecommunications Research Institute): "Method of providing direct communication in internet protocol network." Priority date: 2009-10-06.
• US8014421B2 (Citrix Systems, Inc.): "Systems and methods for adjusting the maximum transmission unit by an intermediary device." Priority date: 2004-07-23.
• US8296437B2 (Logmein, Inc.): "Server-mediated setup and maintenance of peer-to-peer client computer communications." Priority date: 2005-12-29.
• B. Ford, Peer-to-Peer communication across network address translators, MIT Lab, Feb. 17, 2005, pp. 1-14. (Ford)
• P. Srisuresh, State of P2P communication across NATs, RFC 5128, RFC, Mar. 2008, pp. 1-32. (Srisuresh)

Elements of the Independent Claims and Corresponding Prior Art:

The independent claims (Claim 1 and Claim 6) of US 8,780,887 describe a method of network-based communication in a virtual network environment, focusing on direct communication between virtual tunnel routers (TRs) using virtual network prefix information and hole punching, orchestrated by a tunnel mapping controller.

• Virtual Tunnel Routers (Virtual TRs): The concept of "virtual routers" is known in the prior art. For example, US6765881B1 (Rajakarunanayake) discusses "virtual L2TP/VPN tunnel network" and MAC address detection for virtual routers. US20080307519A1 (Avaya Technology Llc) describes a "peer-to-peer network over a virtual private network" which would inherently involve routing functions in a virtualized environment. US20100235481A1 (Lantronix, Inc.) discusses "accessing networked devices without accessible addresses via virtual ip addresses," implying virtual routing.

• Tunnel Mapping Controller: While not explicitly named "tunnel mapping controller," the functionality of a central entity managing tunnels and network information in a virtualized environment is present in prior art. Maekawa (US20070174436A1) describes a "tunnel management apparatus" that manages communication systems. Rajakarunanayake (US6765881B1) mentions "tunnel switch network" where each tunnel switch is "preconfigured with a list of tunnels with which it is associated and a list of domains corresponding to each tunnel," suggesting a form of centralized tunnel management. Moreover, US20110082941A1 (ETRI, an inventor family related patent) discusses "a server to provide direct communication" in an IP network.

• Virtual Network Prefix Information: The use of virtual IP addresses and associated network prefixes for identifying virtual networks and terminals within them is also a known concept. The patent itself states, "A virtual IP has the meaning as an unchangeable identifier on the virtualized network, like identifying respective virtual networks and identifying terminals located in a virtual network area." The use of IP prefixes for network addressing is fundamental to IP networking. Private IP address ranges and their use in virtual networks are well-established. Azure documentation shows that virtual network subnets use standard naming conventions including prefixes.

• Hole Punching Message / Hole Punching: Peer-to-peer (P2P) communication across Network Address Translators (NATs) using "hole punching" techniques was a known method for establishing direct communication. Ford (2005) and Srisuresh (2008) are non-patent literature references explicitly discussing "Peer-to-Peer communication across network address translators." KR20080059900A (한국과학기술정보연구원) explicitly discloses a "System level MPI communication method that supports private IP in grid environment through modified hole punching." Hole punching for reclaiming unused space from a data container on a storage system is also known.

• Establishing a Tunnel: The establishment of tunnels between network entities, including virtual private network (VPN) tunnels over IP networks, is a well-known technology. US6636520B1 (Jason et al.) describes a "Method for establishing IPSEC tunnels." Rajakarunanayake (US6765881B1) also describes a "virtual private tunneling network" for communication across a VPN. The general concept of "tunneling" involves encapsulating packets.

• Direct Communication through an Established Tunnel: Once a tunnel is established between two network entities, direct communication through that tunnel is the inherent purpose and a widely understood function.

Obviousness Combinations:

A person having ordinary skill in the art (PHOSITA) in 2010 would have been familiar with virtual networking, NAT traversal techniques like hole punching, and the use of centralized management entities for network resources.

Combination 1: Devarapalli (US20060130136A1) + KR20080059900A (한국과학기술정보연구원) + Maekawa (US20070174436A1)

• Devarapalli could provide the context of a virtualized network environment for interworking wireless data networks, where direct communication between entities in different network segments would be desirable.
• KR20080059900A clearly teaches "system level MPI communication method that supports private IP in grid environment through modified hole punching" for direct communication. This reference directly addresses the "hole punching" aspect and its application in a network environment for direct communication using private IPs.
• Maekawa discloses a "tunnel management apparatus" which could provide the functionality of a "tunnel mapping controller" to manage tunnels and facilitate communication between virtual tunnel routers. Maekawa’s “tunnel management apparatus” managing tunnels between devices would motivate a PHOSITA to use this for managing the "virtual tunnel routers" envisioned in the present patent.

Motivation to combine: A PHOSITA would be motivated to combine these references to overcome the challenges of direct communication in network environments with NATs/firewalls, as explicitly stated in the background of US8780887. The goal of "providing a method of network-based communication in a virtual network environment capable of direction communication based on a virtual address" would drive the use of established hole punching techniques (from KR20080059900A) within a virtualized network managed by a tunnel management entity (from Maekawa) to achieve direct communication as envisioned in Devarapalli's interworking wireless data networks. The "virtual network prefix information" would be a natural extension of existing IP addressing schemes for managing addresses within such a virtualized environment. The combination would yield a predictable result: enabling direct communication between virtual routers in a virtual network, even through NATs/firewalls.

Combination 2: Rajakarunanayake (US6765881B1) + Ford (2005) / Srisuresh (2008)

• Rajakarunanayake teaches a "virtual L2TP/VPN tunnel network" and "tunnel switches" that are "preconfigured with a list of tunnels with which it is associated and a list of domains corresponding to each tunnel." This provides a clear teaching of virtual tunnel routers and a centralized management concept similar to a "tunnel mapping controller" that manages "virtual network prefix information" (implied by "list of domains" and tunnels).
• Ford (2005) and/or Srisuresh (2008) provide explicit teachings of "Peer-to-Peer communication across network address translators" using "hole punching." These references highlight the problems and solutions related to direct communication through NATs.

Motivation to combine: A PHOSITA, facing the known difficulties of direct communication across NATs in VPNs (as described in Rajakarunanayake), would be motivated to employ known NAT traversal techniques like "hole punching" (from Ford or Srisuresh). The "tunnel switches" in Rajakarunanayake that manage tunnels and domains could readily be adapted to orchestrate the hole punching process and provide the necessary virtual network prefix information to the virtual tunnel routers. The combination would address a known problem (NAT traversal in VPNs) with a known solution (hole punching) in a predictable way to enable direct communication between the virtual tunnel routers.

Conclusion on Obviousness:

Based on the analysis of the independent claims and the prior art references, the claimed methods in US 8,780,887 appear to be obvious under 35 U.S.C. § 103. The core elements of virtual tunnel routers, tunnel mapping controllers, virtual network prefix information, and hole punching for direct communication were all known in the art, and a PHOSITA would have been motivated to combine these known elements in predictable ways to achieve the desired outcome of direct communication in a virtual network environment.