Gateway Cluster Virtual IP Address Assignment for SD-WAN Load Balancing
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Solution Overview
Problem
In software defined wide area networks (SD-WAN), the anchor gateway is not always the same as the DHCP default gateway, leading to potential bandwidth issues and improper loading due to the lack of consideration for both anchor and default gateways in load balancing algorithms, especially when intracluster links between gateways cannot support multiple client devices at scale.
Innovation Solution
Implementing a virtual router redundancy protocol (VRRP) with virtual IP addresses for each combination of gateways and VLANs, allowing the manager gateway to assign a default gateway that matches the anchor gateway, ensuring WAN data traffic does not pass through intracluster links, and modifying DHCP packets to include the correct default gateway address.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the anchor gateway is assigned separately from the DHCP default gateway, then load balancing can be implemented across multiple gateways, but bandwidth bottlenecks and improper loading occur when intracluster links cannot support multiple client devices at scale
Solution Approach 1:
The patent applies preliminary action by pre-assigning the same gateway as both the anchor gateway and the DHCP default gateway for each client device before traffic routing begins. This proactive assignment ensures that WAN traffic flows directly through the anchor gateway without requiring intracluster link traversal, preventing bandwidth bottlenecks before they occur and maintaining network stability as the network scales.
2Reliability
If multiple gateways are deployed in a cluster, then single point of failure is eliminated and graceful failover is provided, but bandwidth issues and improper loading occur due to traffic passing through intracluster links
Solution Approach 1:
The patent applies local quality by optimizing the traffic path for each individual client device based on its specific anchor gateway assignment. Instead of using a generic routing approach that may traverse intracluster links, the system tailors the DHCP default gateway assignment to match each client's anchor gateway, ensuring that local traffic flows efficiently without consuming bandwidth on intracluster links while maintaining the redundancy benefits of the gateway cluster.
3Ease of manufacture
If the DHCP server provides a default gateway independently of the anchor gateway, then DHCP functionality is simplified, but routing efficiency deteriorates due to mismatched gateway assignments
Solution Approach 1:
The patent applies merging by combining the anchor gateway selection and DHCP default gateway assignment into a single coordinated process. The manager gateway that selects the anchor gateway also provides that same gateway as the DHCP default gateway, ensuring that the two gateway assignments are merged and match. This maintains routing efficiency while keeping the DHCP configuration process simple and centralized.
Data Source
AI summary
An example includes a manager gateway of a gateway cluster, comprising processing circuitry and a memory including instructions that cause the gateway to generate a virtual IP address for each gateway of the gateway cluster. The instructions further cause the gateway to receive an indication that a client device has joined a LAN. The instructions further cause the gateway to determine an anchor gateway to which the client device is to be anchored. The instructions further cause the gateway to transmit a first message anchoring the client device to the anchor gateway. The instructions further cause the gateway to transmit a second message offering an address to the client device.