Session continuity in the presence of network address translation
First Claim
1. A method of providing session continuity by a router in the presence of source network address translation (NAT), the method comprising:
- establishing, by the router, a stateful routing session with a remote router including transmitting to the remote router first session metadata allowing the remote router to associate source address information received in session-related packets with the stateful routing session in accordance with a first source NAT status;
running, by the router, a link monitoring protocol with the remote router to detect a change in source NAT status associated with the stateful routing session to a second source NAT status due to one of (a) a change from source NAT disabled to source NAT enabled, (b) a change from source NAT enabled to source NAT disabled, or (c) a change from a first source address translation to a second source address translation; and
sending, by the router, second session metadata in at least a first session packet forwarded to the remote router following detection of the change in source NAT status so that the stateful routing session continues without interruption.
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Accused Products
Abstract
Embodiments of the present invention provide for continuity of “stateful” routing sessions in the presence of source network address translation (NAT). Specifically, a stateful routing session may be moved from one routing path to another routing path, e.g., due to a routing change in the communication network, where the routing paths have different source NAT status. For example, the stateful routing session may be moved from a path having no source NAT to a path having source NAT, from a path having source NAT to a path having no source NAT, or from paths having different source network address translations. When a stateful routing session is moved from an existing routing path to a new routing path, the routers detect the routing change based on the change in source NAT status using a special link monitoring protocol. Upon detecting the change in source NAT status, session metadata is included in at least the first packet forwarded following detection of the change in source NAT status so that the stateful routing session can continue without interruption.
94 Citations
22 Claims
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1. A method of providing session continuity by a router in the presence of source network address translation (NAT), the method comprising:
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establishing, by the router, a stateful routing session with a remote router including transmitting to the remote router first session metadata allowing the remote router to associate source address information received in session-related packets with the stateful routing session in accordance with a first source NAT status; running, by the router, a link monitoring protocol with the remote router to detect a change in source NAT status associated with the stateful routing session to a second source NAT status due to one of (a) a change from source NAT disabled to source NAT enabled, (b) a change from source NAT enabled to source NAT disabled, or (c) a change from a first source address translation to a second source address translation; and sending, by the router, second session metadata in at least a first session packet forwarded to the remote router following detection of the change in source NAT status so that the stateful routing session continues without interruption. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A router comprising:
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a plurality of communication interfaces; a computer storage; and a packet router configured to implement a method of providing session continuity in the presence of source network address translation (NAT), the method comprising; establishing, by the packet router, a stateful routing session with a remote router including transmitting to the remote router first session metadata allowing the remote router to associate source address information received in session-related packets with the stateful routing session in accordance with a first source NAT status; running, by the packet router, a link monitoring protocol with the remote router to detect a change in source NAT status associated with the stateful routing session to a second source NAT status due to one of (a) a change from source NAT disabled to source NAT enabled, (b) a change from source NAT enabled to source NAT disabled, or (c) a change from a first source address translation to a second source address translation; and sending, by packet the router, second session metadata in at least a first session packet forwarded to the remote router following detection of the change in source NAT status so that the stateful routing session continues without interruption. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A computer program product comprising a tangible, non-transitory computer readable medium having embodied therein a computer program that, when run on at least one computer processor, implements a packet router for a router, the packet router implementing a method of providing session continuity in the presence of source network address translation (NAT), the method comprising:
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establishing, by the packet router, a stateful routing session with a remote router including transmitting to the remote router first session metadata allowing the remote router to associate source address information received in session-related packets with the stateful routing session in accordance with a first source NAT status; running, by the packet router, a link monitoring protocol with the remote router to detect a change in source NAT status associated with the stateful routing session to a second source NAT status due to one of (a) a change from source NAT disabled to source NAT enabled, (b) a change from source NAT enabled to source NAT disabled, or (c) a change from a first source address translation to a second source address translation; and sending, by the packet router, second session metadata in at least a first session packet forwarded to the remote router following detection of the change in source NAT status so that the stateful routing session continues without interruption. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A system comprising:
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a first router; and a remote router, wherein; the first router is configured to establish a stateful routing session with the remote router including transmitting to the remote router first session metadata allowing the remote router to associate first source address information received in session-related packets with the stateful routing session in accordance with a first source NAT status, run a link monitoring protocol with the remote router to detect a change in source NAT status associated with the stateful routing session to a second source NAT status due to one of (a) a change from source NAT disabled to source NAT enabled, (b) a change from source NAT enabled to source NAT disabled, or (c) a change from a first source address translation to a second source address translation, and send second session metadata in at least a first session packet forwarded to the remote router following detection of the change in source NAT status so that the stateful routing session continues without interruption; and the remote router is configured to receive the at least first session packet containing the second session metadata for the stateful routing session associated with the change in source NAT status, identify the stateful routing session based on the second session metadata, and update session-related information and affected flows based on header information in the at least first session packet.
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Specification