BIER Flow Table for OpenFlow Multicast Forwarding
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Solution Overview
Problem
The existing OpenFlow technology for multicast packet forwarding requires establishing a corresponding flow table and group table on each forwarding device, leading to high space occupancy and low forwarding efficiency due to the need for multiple entries for each flow, especially when the multicast network topology remains unchanged.
Innovation Solution
Implementing a Bit Index Explicit Replication (BIER) technology within the OpenFlow framework, where a BIER flow table is sent to forwarding devices, allowing multicast packets to be forwarded based on network topology rather than individual flows, reducing the need for multiple tables and enhancing efficiency by only updating the ingress device's BIER flow table when changes occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flow table and group table are established on each forwarding device for each multicast flow, then multicast packet forwarding can be achieved, but the space occupied by entries becomes large and forwarding efficiency becomes low
Solution Approach 1:
The patent segments the multicast forwarding function by separating the control plane (SDN controller) from the data plane (forwarding devices). The SDN controller maintains the global flow table with all multicast routing information, while forwarding devices only maintain minimal local forwarding information. This segmentation allows multicast packets to be forwarded without requiring each forwarding device to store complete flow and group tables for every multicast flow, thereby reducing entry space occupancy while maintaining forwarding capability.
2Reliability
If a flow table and group table are established on each forwarding device for each multicast flow, then multicast packet forwarding can be achieved, but forwarding efficiency becomes low
Solution Approach 1:
The patent introduces the SDN controller as an intermediary between the multicast source and forwarding devices. The controller pre-computes optimal multicast routing paths and installs corresponding flow entries in forwarding devices. When multicast packets arrive, forwarding devices efficiently forward them based on pre-configured flow tables without requiring complex real-time computations. This intermediary approach significantly improves forwarding efficiency by eliminating the need for each device to independently manage complete flow and group tables for every multicast flow.
3Stability of the object's composition
If the network topology remains unchanged, then the same multicast flows continue, but the number of entries in flow tables and group tables increases continuously
Solution Approach 1:
The patent implements a universal flow table structure at the SDN controller that serves all multicast flows simultaneously. Instead of requiring separate flow and group tables for each multicast flow at every forwarding device, the controller maintains a single global flow table that handles multiple multicast flows. This universal approach ensures that when network topology remains stable, the same flow table entries can be reused for multiple flows, preventing continuous increase in the number of entries while maintaining support for multiple multicast groups.
Data Source
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AI summary
An information transmission method, comprising: a control platform generating forwarding information of a bit indexed explicit replication (BIER) network; and the control platform sending, according to the forwarding information of the BIER network, a BIER flow table to a forwarding device through an OpenFlow protocol. The solution solves the problems that, in a forwarding mode for a multicast message in the relevant OpenFlow technology, a space occupied by an entry is larger and the forwarding efficiency is lower because it is necessary to establish a corresponding flow table and group table on each forwarding device for each flow.