ARP Broadcast Optimization via Centralized Gateway Suppression
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Solution Overview
Problem
In centralized network architectures, address resolution requests (ARP/ND) flood the network, consuming significant bandwidth due to the lack of ARP/ND suppression capabilities in low-cost L2 switches, which are commonly used in edge devices, and the inability of centralized gateways to suppress these requests once they reach the target host.
Innovation Solution
Implementing a system where the ingress VTEP forwards ARP/ND requests only to the centralized gateway, allowing it to perform suppression by maintaining an ARP cache and using BGP Extended Communities to mark routes, enabling the centralized gateway to act as a replicator or resolver, thereby reducing the broadcast domain and minimizing bandwidth consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ARP/ND requests are flooded across the network in centralized architectures, then all edge devices can receive the requests, but network bandwidth is consumed significantly
Solution Approach 1:
The patent extracts the ARP/ND suppression function from edge devices and concentrates it at the ingress VTEP and centralized gateway. The ingress VTEP suppresses duplicate ARP requests by maintaining a suppression table, and the centralized gateway performs final suppression before forwarding to edge devices, removing the need for every edge device to process and forward these requests independently.
Solution Approach 2:
The patent introduces the ingress VTEP and centralized gateway as intermediary devices that mediate ARP request distribution. These intermediaries maintain suppression tables and control which ARP requests reach the broadcast domain, acting as intelligent gatekeepers that prevent unnecessary flooding while ensuring legitimate requests are delivered.
2Ease of manufacture
If low-cost L2 switches are used in edge devices, then device cost is reduced, but ARP/ND suppression capabilities are lost
Solution Approach 1:
The patent merges the ARP suppression functionality into the ingress VTEP and centralized gateway, which are already present in the network architecture for other purposes. By combining multiple functions (routing, ARP suppression, request distribution) into these existing centralized components, the patent eliminates the need for expensive ARP suppression capabilities in edge L2 switches.
Solution Approach 2:
The ingress VTEP and centralized gateway are designed to perform multiple functions: they handle routing, maintain suppression tables, control ARP request distribution, and manage broadcast domains. This multi-functionality allows the network to achieve ARP suppression without requiring specialized hardware in edge devices.
3Reliability
If centralized gateways forward ARP requests to all edge devices, then complete network coverage is achieved, but bandwidth consumption increases
Solution Approach 1:
The patent implements preliminary suppression at the ingress VTEP before ARP requests enter the broadcast domain. The ingress VTEP checks its suppression table and only forwards requests that haven't been suppressed, performing the filtering action in advance to prevent unnecessary traffic from consuming network bandwidth.
Solution Approach 2:
The patent applies different handling qualities to different ARP requests based on local conditions at the ingress VTEP and centralized gateway. Requests are selectively suppressed or forwarded based on whether they exist in the suppression table and whether the target host is local or remote, optimizing bandwidth usage while maintaining necessary network coverage.
Data Source
AI summary
One aspect provides a method and system for managing address resolution requests in a network. During operation, a gateway of the network advertises a route for sending address resolution requests and determines whether a cached entry corresponding to an address resolution request received via the route exists in a neighbor table. In response to determining that the cached entry exists, the gateway responds to the address resolution request based on the cached entry; in response to determining that the cached entry does not exist, the gateway replicates the address resolution request to edge devices in the network, thereby facilitating discovery of a target host corresponding to the address resolution request.