SDN Address Resolution Rewriting for Flow Rule Reduction
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Solution Overview
Problem
In software-defined networking (SDN) environments, the scalability of network paths and the overhead of managing flow rules become significant challenges as the number of endpoints and switches increases, leading to resource constraints and high workload demands.
Innovation Solution
The implementation of packet rewriting processes by network controllers, where edge switches act as proxies for endpoint hosts, simplifies network paths by rewriting address resolution packets and managing endpoint databases to reduce the number of flow rules required, thereby minimizing forwarding table resources and improving scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If per-endpoint flow rules are programmed on each switch, then network paths can be precisely controlled, but forwarding table resources are consumed and scalability is limited
Solution Approach 1:
The patent introduces edge switches as intermediary devices that act as proxies for endpoint hosts. Instead of programming per-endpoint flow rules on every switch in the network, the edge switches intercept and rewrite address resolution packets, creating aggregate flow rules that represent multiple endpoints. This intermediary approach maintains precise network path control while dramatically reducing the number of flow rules required on core switches.
Solution Approach 2:
The patent merges multiple per-endpoint flow rules into aggregate flow rules at the edge switches. By combining the forwarding behavior of multiple endpoints into single aggregate rules, the system reduces forwarding table entries on core switches while maintaining the ability to control individual endpoint paths when needed. The edge switches handle the complexity of individual endpoint management, allowing core switches to use simplified aggregate rules.
2Productivity
If the number of endpoints and switches increases, then network coverage and capacity improve, but the overhead of managing flow rules increases significantly
Solution Approach 1:
The patent segments the network into edge switches and core switches with distinct functional roles. Edge switches handle the complex task of managing per-endpoint address resolution and creating aggregate rules, while core switches focus on efficient packet forwarding using the simplified aggregate rules. This segmentation allows the network to scale to more endpoints and switches without proportionally increasing flow rule management overhead, as the edge layer absorbs the management complexity.
3Device complexity
If edge switches act as proxies by rewriting packets, then the number of flow rules is reduced, but additional packet processing is required at the edge
Solution Approach 1:
The patent implements preliminary action by having edge switches perform address resolution packet rewriting at the network edge, before packets enter the core switching fabric. By intercepting and rewriting address resolution packets (such as ARP requests and replies) at the edge switches, the system establishes aggregate flow rules in advance, which then simplify subsequent packet forwarding throughout the network. This preliminary processing at the edge eliminates the need for complex per-endpoint rules on core switches.
Data Source
AI summary
A network controller may rewrite an address resolution request and an address resolution response. The address resolution request may be rewritten by changing a request source link address to a link address of a first switch. The address resolution response may be rewritten by changing a response source link address to a link address of a second switch.