51 results about "Symmetric network" patented technology

Disclosed are systems and methods for peer-to-peer communication over a network between a first node behind a first network address translator (NAT) and a second node behind a second NAT, despite the first NAT and the second NAT intervening between the first and second nodes. The first NAT is a Symmetric NAT. A port prediction is performed wherein the first node constructs a list of predicted transport addresses on the first NAT. A message containing the list of predicted transport addresses is sent from the first node to the second node. A connectivity check is performed with the second node using the predicted transport addresses.

In a symmetric network address translation system using a Simple Traversal of UDP over NAT (STUN) technique and a method for implementing the same, a voice over Internet protocol (VoIP) network includes a STUN server for transmitting, to a private network terminal, a public Internet Protocol (IP) address and first port information of a router which is used for a VoIP call. The private network terminal transmits a session setup request message, including the public IP address and the first port information of the router, through its private IP address and a second port, and the router maps and stores the public IP address and the first port information of the router, and the private IP address and the second port of the private network terminal, and routes a packet received through the public IP address and the first port to the private IP address and the second port. Thus, a VoIP call is performed using the symmetric network address translation system to which the STUN technique is applied.

An apparatus is capable of restoring a clock of a second node in a communication system with a symmetric network construction of a first node that is capable of receiving a Global Positioning System (GPS) signal, and the second node that is not capable of receiving a GPS signal. The method includes identifying synchronization information received from the first node, determining a delay with the first node, generating a clock using the synchronization information and delay, removing a clock phase being out of a reference range in a phase identification interval, dividing the phase identification interval into at least two subdivision intervals, and removing a clock phase being out of a normal operation range of a phase in each subdivision interval.

An intelligent fast switch-over network active tap system enables active monitoring of a network segment connected between network devices. A fail-safe relay subsystem is coupled between a pair of network ports, enabling transmission of network communications signals through a passive cross-connect between the network ports or through an active bridge subsystem. The active bridge subsystem is capable of independently establishing network links with the network devices, and a separate network link with a monitoring device. A controller manages operation of the relay and active bridge subsystems, including switches between passive and active network transmission through the tap system and to determine and establish the active network links subject to symmetric network link parameters and state. Thereby, the network link status of the connected network devices is preserved on switch between active and passive transmission and correctly reflected in the presence of link and power failures.

Handling of multiple connections during NAT traversal for a node behind a symmetric NAT is disclosed. The likelihood of connection failure during symmetric NAT traversal may be reduced by serializing critical time windows after port prediction. Once port prediction has begun for a first connection, port prediction for a subsequent connection may be delayed until a connectivity check has begun for the first connection. This process may be repeated to handle NAT traversal for multiple simultaneous connections to different nodes.

The invention relates to a method for operating a symmetric network address translation NAT (100) setting up sessions between a user terminal (110-1, 110-2) and a server (120-1, 120-2). If a new session is initiated by said user terminal an external IP-address (C) and port (D) representing the desired destination server as well as a public NAT-IP address (X) are determined. Further, a public NAT-IP port is selected. Finally, the NAT sets up the new session based on an appropriate entry representing said new session in a NAT table. In order to save available public NAT-IP ports a new session according to the invention not necessarily represented by a new public NAT-IP port, but by a tuple comprising the public NAT-IP address, the selected public NAT-IP port (Y), the external IP address (C) and the port (D). A new session is set up only if there is an entry of the whole tuple identifying said new session in said NAT-table.

A method and corresponding apparatus is provided for determining the location of a configuration server being connected to a totally symmetric network infrastructure that does not exhibit any symmetry breakers on network level. The configuration server reaches a decision to determine its network-wide unique configuration in order to be able to serve controllers. This decision depends on the plug position of the configuration server under consideration and the assumption of plugging rules governing a “good” network infrastructure. The controllers periodically send network packets that will be marked if they traverse specific connection elements in the network. The origin and the path of a network packet can be determined. The decision making is based on a majority function based on the packets received by the configuration server. If a decision cannot be made, then errors in the cabling structure can be detected.

The invention discloses a method for realizing intranet penetration by using an Internet group management protocol (IGMP), and aims to overcome the shortcoming that a system using a Symmetric network address translator (NAT) cannot actively access another terminal by using one terminal. The method mainly comprises the following steps that: a first terminal transmits a request to a server, and is kept to be connected with the server; a second terminal transmits an IGMP message, establishes a multicast domain, is classified into a group, locally establishes a user datagram protocol (UDP) socket and performs snooping on a port; the second terminal transmits a multicast domain value and a port value to the server, and initiates an access request; the server forwards the access request to the first terminal; and the first terminal transmits data to a second router, and the second router forwards the data to the second terminal. The invention also discloses an intranet penetration system, which comprises at least two terminals, a router and the server. The method is applied to various systems of which each accesses another terminal by using one terminal, particularly to the system using the Symmetric NAT.