Method for enabling communication between two network nodes via a network address translation device (NAT)
A method is provided for enabling communication between first and second network nodes ( 1, 7 ) by way of a network address translation device ( 3, 9 ), which network nodes are each capable of communicating with a server ( 11 ). The first network node ( 1 ) establishes communication with the server ( 11 ) requesting communication with the second network node ( 7 ). The first network node then establishes communication with the second network node by way of the network address translation device ( 3, 9 ), including sending a plurality of first dummy packets from the first network node directly to the second network node. The server ( 11 ) establishes communication with the second network node requesting communication between the second network node and the first network node. Thereafter, the second network node establishes communication with the first network node byway of the network address translation device, including sending a plurality of second dummy packets from the second network node directly to the first network node, transmission of the second dummy packets overlapping with transmission of the first dummy packets. Thereafter data is echanged solely between the first and second network nodes.
1. A method for enabling communication between first and second network nodes ( 1 , 7 ) by way of a network address translation device ( 3 , 9 ), which network nodes are each capable of communicating with a server ( 11 ), which method comprises the steps of:
causing the first network node ( 1 ) to establish communication with the server ( 11 ) requesting communication with the second network node ( 7 );
causing the first network node to establish communication with the second network node by way of the network address translation device ( 3 , 9 ), which step includes sending a plurality of first dummy packets from the first network node directly to the second network node;
causing the server ( 11 ) to establish communication with the second network node requesting communication between the second network node and the first network node;
causing the second network node to establish communication with the first network node by way of the network address translation device, which step includes sending a plurality of second dummy packets from the second network node directly to the first network node, transmission of the second dummy packets overlapping with transmission of the first dummy packets;
thereafter exchanging data directly between the first and second network nodes;
the method including the additional steps of:
determining an error if communication between the network nodes ( 1 , 7 ) is not established within a predetermined time or a predetermined number of dummy packets being transmitted;
in the event that an error is determined, effecting an error auto-reconnect procedure comprising the following further steps:
causing the respective network node ( 1 , 7 ) to communicate the error to the server ( 11 );
causing the server ( 11 ) to communicate the error to the other network node ( 7 , 1 ) which, in turn, re-establishes communication with the server;
causing the server thereafter to communicate identification details of the other network node ( 7 , 1 ) to the respective network node ( 1 , 7 ); and
reverting to the step of causing the first network node ( 1 ) to establish communication with the second network node ( 7 ).
2. A method according to claim 1 wherein the server ( 11 ) maintains a record of identification details of all network nodes ( 1 , 7 ) which may wish to communicate with it.
3. A method according to claim 1 , wherein the network address translation device ( 3 , 9 ) comprises a router.
4. A method according to claim 1 and including the preliminary step of the first and second network nodes ( 1 , 7 ) logging on to the server ( 11 ) to indicate an availability for establishing communication with another network node.
5. A method according to claim 4 wherein the preliminary step and the subsequent steps are effected using different protocols.
6. A method according to claim 1 and including the additional step, prior to the first network node ( 1 ) establishing communication with the second network node ( 7 ), of causing the server ( 11 ) to communicate identification details of the second network node to the first network node.
7. A method according to claim 1 and including the step, prior to the second network node ( 7 ) establishing communication with the first network node ( 1 ), of causing the server ( 11 ) to communicate identification details of the first network node to the second network node.
8. A method according to claim 1 and including, after the step of the first network node ( 1 ) establishing communication with the second network node ( 7 ), the step of causing the first network node to notify the server ( 11 ) that it is establishing communication with the second network node.
9. A method according to claim 1 , wherein an error is determined when the first of the predetermined time and the predetermined number of dummy packets is reached.
10. A method according to claim 1 , wherein the predetermined time is substantially 4 seconds.
11. A method according to claim 1 , wherein the predetermined number of dummy packets is substantially ten packets.
12. A method according to claim 1 , wherein communication of the error to the other network node ( 7 , 1 ) is effected using a different protocol to the other steps of error auto-reconnect.