Hierarchical Address Translation for OpenFlow Packet Forwarding
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Solution Overview
Problem
Existing OpenFlow-based communication systems face inefficiencies in forwarding Layer 3 packets, as they rely on Layer 2 address matching, leading to increased control information entries and queries in relay apparatuses, which hampers accurate destination forwarding when packets need to traverse routers.
Innovation Solution
A control apparatus with first and second control information setting units that convert higher-level destination addresses into lower-level addresses specified in the first control information, allowing accurate forwarding of packets beyond routers by setting first control information based on hierarchical addresses and converting packets when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Layer 2 address matching is used for packet forwarding in OpenFlow switches, then packet forwarding efficiency is improved, but the ability to accurately forward Layer 3 packets to destinations beyond routers deteriorates
Solution Approach 1:
The patent introduces a hierarchical address structure with two levels: first hierarchical addresses (Layer 2 MAC addresses) for local forwarding and second hierarchical addresses (Layer 3 IP addresses) for global routing. This multi-dimensional address system allows the switch to efficiently forward packets within a local network using Layer 2 addresses while simultaneously supporting Layer 3 routing to distant destinations through the hierarchical address translation mechanism
Solution Approach 2:
The control apparatus acts as an intermediary between the relay apparatus and the destination. It receives packets with second hierarchical addresses (IP addresses), translates them into first hierarchical addresses (MAC addresses) appropriate for the local network segment, and forwards them through the relay apparatus. This translation function enables Layer 3 packets to be efficiently forwarded while maintaining Layer 2 forwarding efficiency
2Measurement precision
If flow entries are set for every possible packet destination, then packet forwarding accuracy is improved, but the number of control information entries and queries increases
Solution Approach 1:
The patent implements local quality by creating separate forwarding rules for different address types. First hierarchical addresses (MAC addresses) are used for local network forwarding where high accuracy is needed, while second hierarchical addresses (IP addresses) are used for global routing. This differentiation allows the system to maintain accurate forwarding without creating exhaustive flow entries for every possible destination, as local switches only need to handle Layer 2 forwarding within their segment
Data Source
AI summary
A control apparatus includes: a first control information setting unit configured to set first control information for forwarding packets between predetermined machines in relay apparatuses on a predetermined path on the basis of a first hierarchical address; and a second control information setting unit configured to set, when receiving a packet whose destination address is a second hierarchical address, which is a higher level address than the first hierarchical address, from one of the machines in which the first control information has already been set, via one of the relay apparatuses, second control information for converting a first hierarchical destination address of the packet whose destination address is the second hierarchical address into a first hierarchical address specified in the first control information and forwarding the converted packet, in the relay apparatus.