Peer-to-peer (P2P) connection despite network address translators (NATs) at both ends

• US 7,590,758 B2
• Filed: 12/12/2007
• Issued: 09/15/2009
• Est. Priority Date: 01/15/2003
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Boiri, Kamal Youssef, Takeda, Yutaka
• Primary Examiner(s): Tran; Philip B
• Application Number:
  US11/954,383
• Publication Number:
  US 20080126528A1
• Time in Patent Office: 643 Days
• Field of Search: 709/245, 709/249, 709/220, 709/227, 709223-224, 709/238
• US Class Current: 709/245
• CPC Class Codes: H04L 61/2575 using address mapping retrieval, e.g. simple traversal of user datagram protocol through session traversal utilities for NAT [STUN]
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 65/1104 Session initiation protocol [SIP]
• CPC Class Codes: H04L 67/104 Peer-to-peer [P2P] networks
• CPC Class Codes: H04L 67/55 Push-based network services

Abstract

Methods of operating a first endpoint device (ED) facilitate the making of a peer-to-peer (P2P) connection between the first ED and a second ED despite intervening network address translators (NATs) at both ends. The P2P connection extends across a system compliant with the internet protocol (IP) whose architecture that includes a first network (having at least the first ED and a first NAT), a second network (having at least the second ED and a second NAT) and a third network. The first ED connects to the third network via the first NAT while the second ED connects to the third network via the second NAT. A first such method includes: providing the second ED with the first IP-address/port pair; and providing the second ED with first type-information regarding the type of the first NAT.

Claims

1. A method of determining a port ID for a symmetric network address translator (NAT), the method comprising,

requesting, from a symmetric NAT residing on a first network device, a plurality of port identification numbers (IDs) previously assigned, by the symmetric NAT, for a plurality of distinct connections associated with the symmetric NAT, respectively;

and

receiving information at a second network device regarding the plurality of port IDs from the first network device; and

predicting a port ID for use by the second network device based on a historic pattern for assigning port IDs derived from the information received at the second network device from the first network device.

2. The method of claim 1 where in said predicting step is based on knowledge of two historical port ID numbers.

3. A method of determining a port ID for a symmetric network address translator (NAT), the method comprising:

requesting, a symmetric NAT to map a plurality of port identification numbers (IDs) for a plurality of connections to the symmetric NAT, respectively; and

receiving information regarding the plurality of port IDs by a second network device;

determining a pattern of how the port IDs were assigned by the symmetric NAT from the information received by the second network device; and

predicting, by the second network device, a port ID based on the determined pattern.

4. The method of claim 3 wherein said predicting step is based on knowledge of two previously used port ID numbers.

5. A method of determining a port ID for a symmetric network address translator (NAT), the method comprising:

requesting a first network device having the symmetric NAT to map a plurality of port identification numbers (IDs);

receiving information regarding the plurality of port IDs by a second network device; and

predicting, by the second network device, a port ID based on knowledge of at least one port ID number previously assigned by said NAT.

6. A system for effecting communication between an endpoint device associated with a first network and a client associated with a second network, comprising:

a symmetric network address translator (NAT) coupled between said first and second networks and being configured to map first address and port pairs associated with said first network to second address and port pairs associated with said second network;

said endpoint device having a map request component adapted to communicate with said symmetric NAT to obtain a set of port mappings previously made by said symmetric NAT between said first and second address and port pairs;

said endpoint device further having a prediction component that examines said set of port mappings received and computes a predicted port mapping with which communication between said endpoint device and said client is effected through said symmetric NAT based upon a comparison with change of said set of port mappings.

7. The system of claim 6, wherein the prediction component computes the predicted port mapping with which communication between said endpoint device and said client is effected through said symmetric NAT based upon an increment of port numbers between successive ports of said set of port mappings.