SDN Controller Silent Device Detection via Proactive Packet Forwarding
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Solution Overview
Problem
In Software Defined Networks (SDNs), silent devices that do not actively send packets cannot be detected by the SDN controller, preventing the distribution of forwarding configuration information and thus hindering communication between hosts through established VxLAN tunnels.
Innovation Solution
The method involves an SDN controller receiving a detecting packet from a first device, sending it to all connected switches with downlink port information, allowing the packet to be forwarded through all ports without checking VLAN IDs, and configuring forwarding information based on responses from silent devices to ensure communication across VxLAN tunnels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SDN controller waits for active ARP packets from hosts to distribute forwarding configuration information, then the system maintains simple detection mechanisms, but silent devices cannot be detected and communication is hindered
Solution Approach 1:
The SDN controller proactively sends detecting packets to switches before actual communication needs arise. This preliminary action allows the controller to discover silent devices in advance, obtain their VLAN IDs, and distribute forwarding configuration information before communication is attempted, resolving the contradiction between detection reliability and mechanism complexity
Solution Approach 2:
Detecting packets serve as intermediaries between the SDN controller and silent devices. These packets enable the controller to indirectly discover silent devices by having switches forward them to potential destinations, allowing detection without direct interaction with the silent devices themselves
2Adaptability or versatility
If the switch forwards detecting packets to all downlink ports without VLAN checking, then silent devices can be detected across all network segments, but the forwarding process becomes less efficient
Solution Approach 1:
The system performs excessive forwarding by sending detecting packets to all downlink ports regardless of VLAN matching. This ensures comprehensive coverage and detection of silent devices in any network segment, accepting temporary efficiency loss during the detection phase as a trade-off for complete adaptability
Solution Approach 2:
The detection process is segmented into distinct phases: first, broad forwarding to all ports for comprehensive detection; second, targeted forwarding using obtained VLAN information for actual communication. This segmentation allows the system to achieve high adaptability during detection while maintaining efficiency during normal operation
Data Source
AI summary
A Software Defined Network (SDN) controller receives a detecting packet reported by a first switch and initiated by a first device. The SDN controller sends, for each of switches having an SDN connection with the SDN controller, the detecting packet and information of all downlink ports of the switch to the switch in a way that the switch is capable of sending the detecting packet through the downlink port. The SDN controller receives a response packet which is sent by a second switch and initially generated by a second device in response to receiving the detecting packet from the second switch, wherein an IP address of the second device matches a destination IP address of the detecting packet. The SDN controller sends forwarding configuration information to the second switch in a way that the second switch is capable of configuring a port through which the response packet is received.