Automated NAT traversal for peer-to-peer networks

• US 20060182100A1
• Filed: 02/11/2005
• Published: 08/17/2006
• Est. Priority Date: 02/11/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: He, Li-Wei, Li, Jin
• Granted Patent: US 7,912,046 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/2514 between local and global IP addresses
• CPC Class Codes: H04L 61/2578 without involvement of the NAT server
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols

Abstract

The subject invention relates to systems and methods that facilitate direct network communications between peers that operate behind Network Address Translators. In one aspect, a network communications system is provided. The system includes one or more Network Address Translators (NAT) to communicate data across a network between peers. A protocol selection component that automatically selects among a plurality of protocols according to one or more NAT types in order to determine a subset of the protocols that facilitate communications between the peers.

Claims

1. A network communications system, comprising:

at least one Network Address Translator (NAT) to communicate data across a network between peers; and

a protocol selection component that automatically selects among a plurality of protocols according to one or more NAT types in order to determine a subset of the protocols that facilitate communications between the peers.

2. The system of claim 1, the NAT is a directed Internet connection without NAT functionality, a UPNP NAT, a Full Cone NAT, a Restricted Cone NAT, a Symmetric NAT with ISA functionality, a Symmetric NAT with deterministic port assignment, a generic Symmetric NAT or a Firewall with egress traffic filtering.

3. The system of claim 1, further comprising at least one of a query component to determine and select the NAT types connected to the client component during an initialization sequence or a relay server that interacts with the client component to determine a WAN port of a connection from the client.

4. The system of claim 1, further comprising at least one traversal protocol component to establish connections between clients.

5. The system of claim 4, the traversal protocol component includes at least one of the following functions:

a function for a first client component to obtain a connection vector of a second client component;

a function to attempt a connection from the first client component to a private area network port associated with the second client component; and

a function to attempt at least one connection from the first client component to a wide area network port associated with the second client component.

6. The system of claim 4, the attempt at a connection from the first client component to the wide area network port associated with the second client component further comprises:

a function to call a network function to obtain information relating to a wide area network port for the first client component;

a function to compile the wide area network port of the first client component into a port information list and send the port information list to a relay server associated with the second client component; and

a function to attempt at least one connection from the second client component to a wide area network port associated with the first client component.

7. The system of claim 5, the first client component is associated with a Restricted Cone NAT protocol, and the second client component is associated with an ISA symmetric NAT protocol.

8. A network traversal method, comprising:

transmitting a connection vector from a first client component to a second client component;

attempting a connection from the second client component to a wide area network port associated with the first client component;

compiling a port information list of the second client component;

sending the port information list of the second client component to the first client component; and

attempting at least one connection from the first client component to a wide area network port associated with the second client component.

9. The method of claim 8, further comprising:

attempting a connection from the second client component to a private area network port associated with the first client component.

10. The method of claim 8, wherein compiling a port information list of the second client component further comprises:

transmitting from the second client component at least two connection requests before and after attempting the connection to the wide area network port associated with the first client component to a relay server associated with the second client component to obtain an approximate wide area network port of the second client component.

11. The method of claim 8, wherein

the first client employs a fixed private port assignment in response to each connection request, and

the second client component generates a random private port assignment in response to each connection request.

12. The method of claim 8, the first client component is connected to a Restricted Cone NAT, and the second client component is connected to a symmetric NAT having a deterministic port assignment property.

13. The method of claim 10, further comprising:

verifying a gap distance between ports returned by the connection requests to the relay server; and

re-attempting a connection from the second client component to the wide area network port associated with the first client component if the gap is larger than a predetermined value.

14. A generic port discovery method, comprising:

establishing from a client component m connection sessions in a progression to outside network addresses, each session with n_i, i=1, 2, . . . ,m connections, n and m being positive integers respectively;

automatically determining a port range of the wide area network port with respect to each session; and

compiling a port information list in response to the progression.

15. The method of claim 14, wherein the client component is connected to a symmetric NAT having a deterministic port assignment property.

16. The method of claim 14, further comprising transmitting the port information list across a network to facilitate communications between network peers.

17. The method of claim 14, further comprising the following progression:

establishing before session 1, at least one connection to a relay server;

establishing in session 1, at least n_—

1 connections to an outside network address, and at least one connection to a relay server;

establishing in a session 2, at least n_—

2 connections to an outside network address, and at least one connection to the relay server, establishing in session 3, at least n_—

3 connections to an outside network address, and one connection to the relay server.

18. The method of claim 14, further comprising generating a random private port assignment for each connection to an outside network address or a relay server.

19. The method of claim 17, further comprising reporting an observed WAN port of a connection.

20. The method of claim 14, further comprising:

verifying at least two WAN ports returned from a relay server before and after a connection session,

calculating a number of interfering network traffic patterns, and

discarding a connection session if the number of interfering network traffic patterns is larger than a predetermined value.