Multicast Packet Fast Reroute via Synchronized Port State Database
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional network elements take too long to recover from port failures, leading to increased downtime and packet loss due to slow rerouting of traffic.
Innovation Solution
Implementing a method that uses a synchronized local port state database within the data plane to quickly reroute multicast packets to available ports associated with a multi-link trunk, allowing for automatic redirection of traffic across remaining ports without control plane intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rerouting mechanisms are used, then traffic can be diverted to alternate ports, but the recovery time exceeds 10 milliseconds causing increased downtime and packet loss
Solution Approach 1:
The patent pre-computes and stores alternate egress port mappings in a forwarding table before failures occur. When a port failure is detected, the system immediately uses the pre-computed alternate ports without requiring time-consuming recalculation, achieving recovery within 10 milliseconds
Solution Approach 2:
The patent divides the forwarding decision process into separate components: the control plane computes alternate paths in advance, while the data plane executes immediate switching using pre-stored mappings. This segmentation allows independent optimization of each plane and enables fast recovery
2Ease of operation
If traffic is concentrated on a single designated alternate port, then rerouting can be simplified, but the alternate port becomes overloaded
Solution Approach 1:
The patent distributes traffic to multiple alternate ports based on their individual capacities and current loads rather than concentrating all traffic on a single designated port. Each alternate port handles a portion of the diverted traffic, preventing any single port from becoming overloaded while maintaining simple forwarding rules
3Extent of automation
If control plane intervention is required for rerouting, then routing decisions can be centralized, but the rerouting process becomes slower
Solution Approach 1:
The control plane performs all routing calculations and alternate path computations in advance, storing the results in forwarding tables. When a failure occurs, the data plane immediately executes switching using these pre-computed tables without requiring control plane intervention, achieving both centralized control and fast execution
Solution Approach 2:
The patent replaces the mechanical control plane intervention process with a hardware-based data plane lookup mechanism. The forwarding decision is made through fast hardware table lookups in the data plane rather than through software-based control plane processing, significantly increasing rerouting speed
Data Source
AI summary
A method, apparatus and computer program product for providing a fast re-route of a multicast packet within a network element to an available port associated with a multi-link trunk is presented. A packet is received by a Forwarding Data Unit (FDU) in a data plane of a network element and a determination made that the packet is a multicast packet. The packet is forwarded to all egress FDUs having at least one port associated with at least one receiver of the multicast packet. A lookup is performed by each egress FDU in a synchronized local port state database to find a port for each receiver that is in an UP state. The packet is forwarded out the port to a receiver when the port is in the UP state and dropped when the port is in the DOWN state.