Segment Routing Egress Peer Engineering BGP Control
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Solution Overview
Problem
Current Border Gateway Protocol (BGP) technologies lack finer grained control and external influence over egress route selection in computer networks, particularly when multiple paths exist to a destination address or prefix, limiting the ability to force specific egress paths in complex network configurations.
Innovation Solution
The implementation of Segment Routing (SR)-based Egress Peer Engineering (EPE) allows a centralized controller to program egress peer policies at ingress border routers or hosts, using BGP Peering Segments and Extended Community attributes to steer traffic through specific egress peers and interfaces, enabling efficient egress point engineering and automated fast reroute mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If BGP best path selection techniques are used to handle multiple AS egress options, then routing decisions can be made based on paths and network policies, but finer grained control and external influence over egress route selection cannot be achieved
Solution Approach 1:
The patent introduces BGP Peering Segments as intermediary constructs that enable centralized control over egress route selection. These segments act as mediators between the BGP routing protocol and the underlying peering relationships, allowing external influence on path selection without modifying BGP's core operation. The segments provide a layer of abstraction that enables fine-grained control while maintaining compatibility with existing BGP infrastructure.
Solution Approach 2:
The patent segments the egress path selection process into discrete BGP Peering Segments, each representing a specific peering relationship or egress point. This segmentation allows independent control of different egress paths while maintaining the overall routing structure. By dividing the control space into manageable segments, the system achieves finer granularity without proportionally increasing complexity.
2Adaptability or versatility
If multiple border routers provide valid paths to the same destination, then network redundancy and flexibility are improved, but the ability to force specific egress paths is limited
Solution Approach 1:
The patent changes the parameters available for route selection by introducing BGP Peering Segments with specific attributes that encode peering relationships, interfaces, and routing policies. These parameter changes enable deterministic selection among multiple valid paths while preserving the flexibility to adapt to different network conditions. The segments provide additional dimensions for route differentiation beyond traditional BGP path attributes.
3Extent of automation
If centralized control over egress routing is implemented, then granular control over traffic routing is achieved, but compatibility with existing BGP infrastructure must be maintained
Solution Approach 1:
The patent designs BGP Peering Segments to serve multiple functions simultaneously: they encode peering relationship information, define egress path selection criteria, and interface with existing BGP routing mechanisms. This multi-functionality allows centralized control to be implemented without requiring separate dedicated infrastructure, reducing deployment complexity while achieving granular routing control.
Data Source
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AI summary
In one embodiment, a controller device in a computer network domain learns border gateway protocol (BGP) egress peering segments from one or more border routers of the domain, and determines a selected flow to segment route via a particular egress peering segment, the selected flow from a given routing device within the domain to a given destination of a remote domain. As such, the controller device may then instruct the given routing device to segment route the selected flow via the particular egress peering segment. In another embodiment, an egress border router shares its BGP egress peering segments, and receives a flow to segment route. The egress border router may determine, from a segment route contained within the flow, to which particular egress peering segment of the border router to segment route the flow, and forwards the flow out of the domain via the particular egress peering segment.