Upstream Downstream Routing Policy Segmentation for ISP Traffic Monitoring
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Solution Overview
Problem
Conventional methods for maintaining VRF information at a PE network node in a hub and spoke topology fail to ensure that traffic between subscribers traverses a central link between a Service Provider Wholesale network and an ISP domain, leading to missed opportunities for monitoring and increased costs for ISPs, as traffic is often routed directly between subscribers without passing through the ISP network.
Innovation Solution
Maintaining separate upstream and downstream routing policy information at a network node to force traffic to travel through specific nodes, ensuring that upstream traffic is routed through a hub node for monitoring and accounting purposes, even if a shorter path exists directly between subscribers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If separate upstream and downstream routing policy information is maintained at a PE node, then traffic can be forced to traverse through the ISP network for monitoring and accounting, but the routing complexity and overhead at the PE node increases
Solution Approach 1:
The patent segments the routing policy information into separate upstream and downstream routing tables at the PE node. The upstream routing table contains routes for traffic originating from subscribers, while the downstream routing table contains routes for traffic destined to subscribers. This segmentation allows the PE node to enforce traffic traversal through the ISP network by consulting the appropriate routing table based on traffic direction, thereby maintaining monitoring capability while managing complexity through structured separation.
Solution Approach 2:
The patent introduces an intermediary routing policy mechanism that acts as a mediator between the PE node and the core network. The separate upstream and downstream routing policies serve as intermediary structures that guide traffic flow through the ISP network infrastructure, enabling monitoring and accounting functions without requiring direct complex control at every PE node. This intermediary routing layer simplifies the overall system complexity while preserving traffic visibility.
2Productivity
If VRF information is maintained at the PE node to enable direct routing between subscribers, then routing efficiency is improved, but the ability to monitor and account for traffic through the ISP network is lost
Solution Approach 1:
The patent segments routing functionality into two distinct routing tables: an upstream routing table for subscriber-originated traffic and a downstream routing table for subscriber-bound traffic. This segmentation enables the PE node to efficiently route traffic while maintaining visibility. By consulting the upstream routing table for outgoing traffic and the downstream routing table for incoming traffic, the system achieves routing efficiency comparable to direct routing while ensuring all traffic passes through the ISP network infrastructure for monitoring and accounting.
Solution Approach 2:
The patent applies local quality by making the routing behavior specific to the traffic direction and origin. The upstream routing table is optimized for efficiency in handling subscriber-originated traffic, while the downstream routing table is optimized for delivering traffic to subscribers. This localized optimization of routing quality for different traffic flows enables the system to achieve high routing efficiency for each direction while maintaining overall traffic visibility through the ISP network.
3Loss of information
If multiple separate VRF instances are created for each subscriber to enforce traffic routing through the hub, then traffic monitoring is enabled, but the computational overhead and memory usage at the PE node increases
Solution Approach 1:
The patent merges the routing information for multiple subscribers into two consolidated routing tables (upstream and downstream) at the PE node, rather than maintaining separate VRF instances for each subscriber. The upstream routing table aggregates routing information for all subscribers originating traffic, and the downstream routing table aggregates routing information for all subscribers receiving traffic. This merging approach enables traffic monitoring for all subscribers while significantly reducing the memory resources and computational overhead compared to maintaining individual VRF instances for each subscriber.
Solution Approach 2:
The upstream and downstream routing tables serve universal functions for all subscribers connected to the PE node. Instead of creating specialized VRF instances for each subscriber, these universal routing tables handle routing decisions for all subscribers in a hub-and-spoke topology. The upstream table universally handles subscriber-originated traffic, and the downstream table universally handles subscriber-bound traffic, enabling a single PE node to efficiently monitor and route traffic for multiple subscribers with reduced resource consumption.
Data Source
AI summary
A first network node maintains separate routing policy information to forward network traffic depending on a direction of the network traffic. Upstream routing policy information at the first node identifies a second node to forward upstream traffic received from at least a first client communicating through the first node. Downstream routing policy information at the first node identifies how to forward downstream network traffic received from another node to the first client. By preventing use of the downstream policy routing information by the first client to route upstream network traffic, the first node is able to forward traffic along a path that the network traffic otherwise would have not traveled. For example, network traffic communicated through the first node can be forced to travel through another network node through which it would have not otherwise have passed if the downstream policy information was available to route the network traffic.