Gateway-Mediated Proxy ARP for Isolated Subscriber LANs
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Solution Overview
Problem
Existing IP address allocation methods in distributed LAN environments, such as those using virtual CPE platforms, result in inefficient use of IP addresses and prevent direct communication between subscriber devices due to layer 2 isolation, leading to connectivity issues.
Innovation Solution
Implementing a proxy ARP module in the MS-BNG to facilitate communication between subscriber devices by proxying their MAC addresses, allowing them to communicate as if on the same LAN while maintaining domain isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a /24 routing prefix is used to provide static IP service to multiple subscribers via virtual CPE, then IP address utilization efficiency is improved, but subscriber devices cannot communicate directly with each other due to layer 2 isolation
Solution Approach 1:
The gateway acts as an intermediary by implementing proxy ARP functionality. When a subscriber device sends an ARP request for another subscriber's IP address, the gateway intercepts the request and responds with its own MAC address, enabling the first subscriber to send packets to the gateway which then forwards them to the second subscriber. This mediator approach resolves the contradiction by maintaining layer 2 isolation while enabling communication between subscribers.
2Object-affected harmful factors
If layer 2 isolation is implemented in virtual CPE platform to maintain security and privacy, then security and privacy are improved, but direct communication between subscriber devices is prevented
Solution Approach 1:
The gateway serves as a trusted intermediary that maintains layer 2 isolation for security while enabling communication. The proxy ARP mechanism allows the gateway to intercept ARP requests and provide appropriate responses, facilitating communication between subscribers without breaking the layer 2 isolation boundary. This preserves security and privacy while providing the needed communication capability.
3Speed
If ARP broadcast is used for direct communication between subscriber devices, then communication speed is improved, but ARP broadcast fails in distributed LAN environment due to isolation rules
Solution Approach 1:
The gateway intercepts ARP broadcast requests and provides proxy responses, effectively mediating the address resolution process. Instead of ARP broadcasts failing due to isolation rules, the gateway captures these broadcasts and responds with its own MAC address, allowing the communication to proceed through the gateway to the intended destination. This maintains the speed advantage of ARP while ensuring reliability in the isolated environment.
Data Source
AI summary
Methods and systems proxy address resolution protocol processing in a distributive local area network is described. The method for proxy address resolution protocol processing includes sending, by a first subscriber device, an address resolution protocol processing broadcast to obtain a second subscriber device address, wherein the first subscriber device and the second subscriber device are in isolated routing prefix domains within a routing prefix, receiving, by the first subscriber device from a gateway, a second subscriber device proxy address for the second subscriber device, and communicating, between the first subscriber device and the second subscriber device via the gateway, using the second subscriber device proxy address.