Core And Edge Router Route Segmentation for FIB Scalability
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Solution Overview
Problem
Existing network operating system designs for carrier-grade core and edge routers require all routes to be programmed into each linecard, limiting scalability and consuming critical resources once the maximum routing table size is reached.
Innovation Solution
A distributed, disaggregated cluster (DDC) router architecture that splits the routing table based on route utilization, using a first set of DCPs for high-volume routes and a second set for low-volume routes, with a centralized control plane to manage and optimize memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If all routes are programmed into each linecard, then routing functionality is complete, but scalability is limited and critical resources are consumed
Solution Approach 1:
The routing table is segmented and distributed across multiple linecards in the router. Each linecard maintains a portion of the routing table, allowing the system to scale by adding more linecards. This segmentation enables the router to handle larger routing tables (up to 4 million IPv4 and 2 million IPv6 routes) without consuming excessive resources on a single card, thus resolving the contradiction between complete routing functionality and scalability.
2Adaptability or versatility
If routing table size increases, then more routes can be supported, but memory resources become critical and scarce
Solution Approach 1:
The routing table is divided and distributed across multiple linecards, so that memory resources are shared across the entire router system rather than concentrated on a single card. This segmentation allows the router to support a larger total number of routes (up to 4 million IPv4 and 2 million IPv6) while distributing the memory burden, thus avoiding the memory resource constraints that would exist in a centralized routing table design.
3Adaptability or versatility
If routing table is distributed, then scalability improves, but route lookup complexity increases
Solution Approach 1:
The control plane performs preliminary actions by programming route information into the data plane of appropriate linecards before packet forwarding occurs. This pre-programming eliminates the need for complex real-time route lookups during data forwarding, as the routing decisions are already made and stored in the linecards. This preliminary action resolves the contradiction by enabling distributed routing scalability while simplifying the actual packet forwarding process.
Data Source
AI summary
Aspects of the subject disclosure may include, for example, a routing device in a network, the routing device including an ingress/egress linecard; another linecard; a fabric; a processing system including a processor; and a memory that stores executable instructions that, when executed by the processing system, facilitate performance of operations of maintaining a forwarding information base (FIB) for routes through the routing device; moving low-volume routes of the FIB to the another linecard; and moving high-volume routes of the FIB to the ingress/egress linecard, wherein the ingress/egress linecard looks up a route of an incoming data packet, determines whether the incoming data packet bears a high-volume route prefix, forwards the incoming data packet bearing the high-volume route prefix through the fabric and out of the routing device, and sends the incoming data packet bearing a low-volume route prefix through the fabric to the another linecard, and wherein the another linecard forwards the incoming data packet received from the ingress/egress linecard out of the routing device. Other embodiments are disclosed.