The present invention describes a system and method for communicating voice and data over a packet-switched network that is adapted to coexist and communicate with a legacy PSTN. The system permits packet switching of voice calls and data calls through a data network from and to any of a LEC, a customer facility or a direct IP connection on the data network. The system includes soft switch sites, gateway sites, a data network, a provisioning component, a network event component and a network management component. The system interfaces with customer facilities (e.g., a PBX), carrier facilities (e.g., a LEC) and legacy signaling networks (e.g., SS7) to handle calls between any combination of on-network and off-network callers. The soft switch sites provide the core call processing for the voice network architecture. The soft switch sites manage the gateway sites in a preferred embodiment, using a protocol such as the Internet Protocol Device Control (IPDC) protocol to request the set-up and tear-down of calls. The gateway sites originate and terminate calls between calling parties and called parties through the data network. The gateway sites include network access devices to provide access to network resources. The data network connects one or more of the soft switch sites to one or more of the gateway sites. The provisioning and network event component collects call events recorded at the soft switch sites. The network management component includes a network operations center (NOC) for centralized network management.

Voice over data telecommunications network architecture

The present invention provides a firewall that achieves maximum network security and maximum user convenience. The firewall employs “envoys” that exhibit the security robustness of prior-art proxies and the transparency and ease-of-use of prior-art packet filters, combining the best of both worlds. No traffic can pass through the firewall unless the firewall has established an envoy for that traffic. Both connection-oriented (e.g., TCP) and connectionless (e.g., UDP-based) services may be handled using envoys. Establishment of an envoy may be subjected to a myriad of tests to “qualify” the user, the requested communication, or both. Therefore, a high level of security may be achieved. The usual added burden of prior-art proxy systems is avoided in such a way as to achieve fall transparency-the user can use standard applications and need not even know of the existence of the firewall. To achieve full transparency, the firewall is configured as two or more sets of virtual hosts. The firewall is, therefore, “multi-homed,” each home being independently configurable. One set of hosts responds to addresses on a first network interface of the firewall. Another set of hosts responds to addresses on a second network interface of the firewall. In one aspect, programmable transparency is achieved by establishing DNS mappings between remote hosts to be accessed through one of the network interfaces and respective virtual hosts on that interface. In another aspect, automatic transparency may be achieved using code for dynamically mapping remote hosts to virtual hosts in accordance with a technique referred to herein as dynamic DNS, or DDNS.

Firewall providing enhanced network security and user transparency

A feedback control system for congestion prevention in a cell (packet) switching communication network is described. Congestion control is accomplished by controlling the transmission rate of bursty traffic in the presence of high priority, voice, low speed statistical, high speed deterministic and multicast data. Because bursty traffic is relatively insensitive to delay, adequate buffercapacity can be provided at the network nodes in order to minimize bursty data cell loss. By monitoring the buffer queue lengths at the nodes, a control signal can be generated at each intermediate node indicating the state of congestion. Excess queue length indicates incipient congestion while short queue lengths indicate excess capacity. Queue status is forwarded to the destination node where it is interpreted and sent back to the source node as a feedback rate control signal using a 2-bit code. The source node regulates the rate of bursty data transmission over the cell network in accordance with the feedback control signal thus minimizing congestion and concomitant data loss while efficiently utilizing available network bandwidth.

Congestion control for cell networks

A system and method for providing telephone type services over the internetwork commonly known as the Internet. Public switched telephone networks utilizing program controlled switching systems are arranged in an architecture with the Internet to provide a methodology for facilitating telephone use of the Internet by customers on an impromptu basis. Provision is made to permit a caller to set-up and carry out a telephone call over the Internet from telephone station to telephone station without access to computer equipment, without the necessity of maintaining a subscription to any Internet service, and without the requiring Internet literacy or knowledge. Calls may be made on an inter or intra LATA, region or state, nationwide or worldwide basis. Billing may be implemented on a per call, timed, time and distance or other basis. Usage may be made of common channel interoffice signaling to set up the call and establish the necessary Internet connections and addressing. Calls may be made from telephone station to telephone station, from telephone station to computer or computer to telephone station.

Internet telephone service

A communication system providing telephony communication across combined circuit switched and packet switched networks, such as a telephone network and the Internet, which are connectable to terminals, such as telephones and computers, for selective communication therebetween. The communication system includes an authorization and account control object in the packet switched network, multiple gateways between the circuit switched and packet switched networks providing controlled connectivity between those networks, and an information retrieval object in the packet switched network, wherein the authorization and account control object maintains a substantially real time record of user accounts and usage, and the information and retrieval object provides substantially real time retrieval of selected information from the authorization and account control object. The retrieval object provides on demand to terminals which provide authentication for access to an identified account information regarding that account. The information regarding the account is substantially real time information including information with respect to communications in progress, which are chargeable to the account which has been authenticated. The authorization and account control object is preferably a unitary logical object having distributed instances thereof handling multitudinous accounts of widely separated terminals. The retrieval object provides isolation of the authorization and account control object permitting simultaneous multitasking by the authorization and account control object and the retrieval object respectively.

Network session management

A packet format for accurately transporting signaling information in a packet network is described. The packet format comprises a burst count, a sequence number, a burst time, and a signaling status bit. The burst count is for indicating a burst to which the packet belongs. The sequence number is for identifying a first packet of the burst. The burst time is for selectably indicating (1) a time delay from onset to a packet node bus for the first packet of the burst and (2) a time interval between successive signaling bit transitions.

Method and apparatus for packet communications signaling

A method and apparatus for converting a signal by reading a first signal that is represented in a first format. The first signal is used as an index into a lookup table, the first table containing entries representing signals in a second format modified by a gain. The first table outputs a second signal responsive to the index provided by the first signal, wherein the second signal is represented in a second format.

Shrikanth S. Kattemalalavadi

Papers

Method and apparatus for packet communications signaling

Integrated PCM level control and conversion using a lookup table