SDN Switch IP Rewriting for SIP Load Balancing
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Solution Overview
Problem
Current load balancing methods for Session Initiation Protocol (SIP) traffic in Software Defined Networking (SDN) networks, particularly using DNS-based approaches, are inefficient as they require universal RFC 3263 style DNS resolution, do not provide a single IP address appearance for signaling, and complicate horizontal scaling by necessitating updates to DNS infrastructure.
Innovation Solution
A load balancing scheme utilizing IP address rewriting and forwarding techniques within an SDN-enabled network, specifically with OpenFlow switches, to distribute SIP traffic across a cluster of Session Border Controllers (SBCs), eliminating the need for DNS-based load sharing and enabling horizontal scaling without additional DNS infrastructure requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DNS-based load balancing is used, then generic and widely applicable load balancing is achieved, but it requires universal RFC 3263 style DNS resolution support which is not available in all networks
Solution Approach 1:
The patent introduces an SDN controller as an intermediary between the SBC cluster and DNS-based load balancing. The controller receives DNS queries, determines the appropriate SBC based on load conditions, and returns targeted IP addresses. This mediator approach allows the system to achieve DNS-based load balancing without requiring all networks to support RFC 3263 style DNS resolution, as the SDN controller handles the translation and routing intelligence.
2Productivity
If DNS-based load balancing is used, then load distribution is achieved, but it does not provide a single IP address appearance for signaling
Solution Approach 1:
The patent merges the load balancing function with the IP address appearance function by having all SBCs in the cluster share a common virtual IP address. The SDN controller manages the mapping between this shared IP and individual SBC addresses, allowing the system to provide both efficient load distribution and a unified IP appearance for signaling without increasing complexity at the client side.
3Productivity
If DNS-based load balancing is used, then load sharing is achieved, but it complicates horizontal scaling as DNS infrastructure must be updated when SBC instances are added or removed
Solution Approach 1:
The patent implements dynamic load balancing where the SDN controller continuously monitors SBC load conditions and dynamically updates routing decisions. When SBC instances are added or removed, the controller automatically detects these changes and adjusts the load distribution without requiring DNS infrastructure updates. This dynamic approach enables horizontal scaling while maintaining operational simplicity.
4Productivity
If SDN switch packet processing is isolated, then linear scalability with networking capacity is achieved, but the system requires sophisticated flow table entry management
Solution Approach 1:
The patent segments the packet processing function by installing flow table entries in SDN switches at strategic points in the network. Each flow table entry handles specific traffic patterns, allowing the system to scale linearly with networking capacity. The segmentation of processing responsibilities between the SDN controller (decision-making) and SDN switches (packet processing) manages complexity while achieving high scalability.
Data Source
AI summary
Methods and apparatus for providing load balancing in a Software Defined Network (SDN). An exemplary embodiment includes the steps of: receiving by a Session Border Controller (SBC) cluster leader a first SIP invite message including a source IP address, assigning responsibility for processing the received message to a first SBC in a cluster of SBCs, and initiating by the first SBC installation of a first flow table entry into SDN switches used to control packet routing in an SDN network, the first flow table entry controlling SDN switches into which the first flow table entry is installed to replace a destination IP address in received packets which satisfy matching criteria of the first flow table entry with a first SBC IP ingress address of the first SBC and to route received packets matching the criteria of the first flow table entry based on the first SBC IP ingress address.