Method and system for path identification in packet networks
First Claim
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1. A method of storing historical routing information in a routing domain operating according to a link state routing protocol, comprising the steps of:
- storing a plurality of routing events advertised in a routing domain as they are received over time;
identifying a set of time instants for which a complete context of routing and topology information of the routing domain will be maintained;
at each time instant identified in the identifying step, constructing at least one time-stamped routing information context by storing data structures representing current topology and routing state of the routing domain; and
for each of the time-stamped routing information contexts, constructing a time ordered list of routing events as the events are received over time until the next time instant identified in the identifying step.
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Abstract
A method and system for extracting and building end-to-end route information in a multi-area Internet protocol (IP) autonomous system (AS) is disclosed. The method and system enable a user, such as a network administrator, to explicitly identify a full set of paths (links and routers) that a given IP packet would potentially traverse from its entry point in the source area of the AS where it originates until its exit point in its intended destination area.
45 Citations
5 Claims
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1. A method of storing historical routing information in a routing domain operating according to a link state routing protocol, comprising the steps of:
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storing a plurality of routing events advertised in a routing domain as they are received over time;
identifying a set of time instants for which a complete context of routing and topology information of the routing domain will be maintained;
at each time instant identified in the identifying step, constructing at least one time-stamped routing information context by storing data structures representing current topology and routing state of the routing domain; and
for each of the time-stamped routing information contexts, constructing a time ordered list of routing events as the events are received over time until the next time instant identified in the identifying step. - View Dependent Claims (2)
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3. A method of identifying of path information in a routing domain operating according to a link state routing protocol, comprising:
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storing a plurality of routing events advertised in a routing domain as they are received over time;
identifying a set of time instants for which a complete context of routing and topology information of the routing domain will be maintained;
at each time instant identified in the identifying step, constructing at least one time-stamped routing information context by storing data structures representing a current topology and routing state of the routing domain;
for each of the time-stamped routing information contexts, constructing a time ordered list of routing events as they are received over time until the next time instant identified in the identifying step;
specifying a starting point in the routing domain, a destination address in the routing domain, a starting time, and an ending time;
reviewing the time-stamped routing information contexts to identify the context having a time stamp that is latest yet still precedes contexts with a time-stamp preceding the starting time;
constructing at least one updated time-stamped routing information context by sequentially processing routing events from the time ordered list of routing events associated with the time-stamped routing information context until reaching the last routing event having a time-stamp that precedes the starting time; and
constructing path information between the starting point and the destination address using the updated time-stamped routing information context. - View Dependent Claims (4, 5)
identifying a plurality of paths from the updated time-stamped routing information context; and
assembling a subset of the plurality of paths into a least cost path between the starting point and the destination address.
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5. The method of claim 4 wherein identifying a plurality of paths comprises identifying a plurality of paths through which the destination address is reachable.
Specification