# US 2014/0153569 A1 · Call Set-Up Systems

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- Number: US 2014/0153569 A1
- Document ID: US20140153569A1
- Status: Published application
- Kind: A1
- Application number: 14/175,931
- Filed: 2014-02-07
- Published: 2014-06-05
- Earliest claimed: 2003-11-08
- Assignees: Ericsson Inc.
- Applicants: Ericsson AB
- Inventors: John Aubrey Allen
- Web page: https://patentgrep.com/patent/US20140153569A1

## CPC

- H04L 65/1069: Session establishment or de-establishment
- H04L 61/00: Network arrangements, protocols or services for addressing or naming
- H04L 61/2528: {Translation at a proxy}
- H04L 61/2546: Arrangements for avoiding unnecessary translation
- H04L 61/2564: {for a higher-layer protocol, e.g. for session initiation protocol [SIP]}
- H04L 61/2591: {Identification of devices behind NAT devices}
- H04L 65/1104: Session initiation protocol [SIP]
- H04L 67/14: Session management (for real-time applications in data packet communications networks H04L65/1066)
- H04L 69/329: in the application layer [OSI layer 7]
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A call set-up system sets up a call, which may be a voice call, between terminals through a plurality of packet switched networks using call agents. The networks are interconnected by network address translation (NAT) devices, and the messages to successive call agents include media addresses in the associated networks for the actual data packets of the call when it has been set up. The call set-up message includes the media address sent to at least some preceding call agents enabling NAT resources to be saved. The call agents can be incorporated into NAT devices, and the media addresses can be encrypted or in the form of a reference.

## Claims

### Claim 1

A call set-up system, for the set-up of calls in a plurality of packet-switched networks connected to each other by network address translation (NAT) devices using a plurality of call agents, comprising means to send messages to successive call agents, which messages include address information for media packets within networks associated with the call agents, to define the media path of the call, at least some of the messages also including address information for media packets sent to preceding call agents involved in the set-up of the call.