Methods and apparatus for selecting a media proxy
First Claim
1. A method of selecting a media proxy for transmitting a media stream along a path comprising,(a) receiving a path setup request which specifies data endpoints for the path,(b) traversing a nodular network model in a predetermined pattern dependent on the specified media endpoints,(c) checking for a list of media proxies at each node traversed during traversal of the nodular network model, wherein a plurality of media proxies is linked to at least one of the nodes in the nodular network model in a list,(d) determining the availability of at least one of the media proxies;
- (e) selecting a media proxy from the list found during traversal of the nodular network model as the media proxy for the path using a predetermined selection policy.
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Abstract
In a packet based (typically IP) network, network address translation is frequently used to overcome the problem of dwindling address spaces. However, network address translation prevents the operation of many of the complex protocols used for transmission of media streams for example, data such as voice over IP or video over IP. Accordingly, media proxy devices are used to allow such data to traverse NAT boundaries. However, media proxy devices are expensive and therefore scarce and the selection of an optimum media proxy is important to obtain optimum functionality and cost effectiveness within the network. By providing a call agent in the network with a simple model of the network and providing information concerning optimum media proxies for different parts of the network, the problem of selecting an optimum media proxy during path set up is overcome.
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Citations
17 Claims
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1. A method of selecting a media proxy for transmitting a media stream along a path comprising,
(a) receiving a path setup request which specifies data endpoints for the path, (b) traversing a nodular network model in a predetermined pattern dependent on the specified media endpoints, (c) checking for a list of media proxies at each node traversed during traversal of the nodular network model, wherein a plurality of media proxies is linked to at least one of the nodes in the nodular network model in a list, (d) determining the availability of at least one of the media proxies; (e) selecting a media proxy from the list found during traversal of the nodular network model as the media proxy for the path using a predetermined selection policy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- 12. A call agent arranged to setup a media path between data endpoints in networks separated by network address translation and further arranged to read a model of the network formed as a plurality of nodes which has a plurality of media proxies linked to at least one node of the plurality of nodes in a list, to receive a path setup request which specifies media endpoints for the media path, to read the model and traverse the model in a predetermined pattern dependent on the specified media endpoints, to check for a list of media proxies at each node traversed during traversal of the model, determine the availability of the media proxy and to select a media proxy from the list found during traversal of the model as the media proxy for the media path.
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16. A computer program embodied in a memory and adapted to execute on a processor in a call agent which is arranged to setup a media path between data endpoints in networks separated by network address translation and during execution to cause the call agent to read a model of a network formed as a plurality of nodes which has a plurality of media proxies linked to at least one node of the plurality of nodes in a list, to receive a path setup request which specifies media endpoints for the media path, to read the model and traverse the model in a predetermined pattern dependent on the specified media endpoints, to check for a list of media proxies at each node traversed during traversal of the model, to determine the availability for at least one media proxy and to select a media proxy from the list found during traversal of the model as the media proxy for the media path.
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17. A call agent arranged to setup a media path between media endpoints in networks separated by a boundary which blocks media streams and further arranged to read a model of a network formed as a list of nodes and a default global pool of media proxies which are arranged to permit traversal of the boundary by the media stream and which are associated in a list with the model, to receive a media path setup request which specifies the media endpoints for a path, to read the model and traverse the model in a predetermined pattern dependent on the specified media endpoints, to check for a linked media proxy at each node traversed during traversal of the model, and to select a media proxy as the media proxy for the path from the default global pool if no proxies are found during traversal of the model.
Specification