SDN Control Apparatus for Seamless Wireless Handover
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Solution Overview
Problem
Current network systems face challenges in achieving seamless handover of host devices between different subnetworks, leading to increased handover time and packet loss due to IP address changes during Layer-3 handover operations.
Innovation Solution
An SDN-based network system with a control apparatus that maintains the IP address of host devices by dynamically adjusting flow tables and returning address resolution response packets, thereby avoiding Layer-3 handover and ensuring continuous network connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Layer-3 handover operation is performed to hand over host device between different subnetworks, then network connectivity is maintained, but handover time increases and packet loss occurs due to IP address changes
Solution Approach 1:
The control apparatus pre-allocates the same IP address to the host device before handover occurs. When the host device moves to a new access device, the IP address is already reserved and ready, eliminating the need for IP address reassignment during handover and reducing handover time
Solution Approach 2:
The control apparatus acts as an intermediary between the host device and network devices. It manages IP address allocation and maintains binding information, coordinating the handover process to ensure seamless IP address preservation without requiring traditional Layer-3 handover procedures
2Reliability
If Layer-3 handover operation is performed to hand over host device between different subnetworks, then network connectivity is maintained, but packet loss occurs due to IP address and socket changes
Solution Approach 1:
The control apparatus pre-allocates and reserves the same IP address for the host device before handover. This preliminary action ensures that when the host device connects to a new access device, the IP address is already assigned and bound, preventing packet loss that would otherwise occur during IP address reassignment
Solution Approach 2:
The control apparatus maintains a copy of the binding information (IP address, MAC address, access device identifier) in its database. This copy allows the control apparatus to quickly retrieve and maintain the correct IP address binding during handover, ensuring continuous connectivity without packet loss
3Adaptability or versatility
If traditional handover procedures are used, then host device can move between access devices, but TCP session connection is interrupted due to IP address changes
Solution Approach 1:
The control apparatus pre-allocates the same IP address to the host device before handover occurs. This preliminary IP address reservation ensures that the host device maintains the same IP address across different access devices, preventing TCP session interruption while allowing device mobility
Solution Approach 2:
The control apparatus serves as an intermediary that manages IP address allocation and maintains binding information. It coordinates the handover process to preserve the host device's IP address, thereby maintaining TCP session continuity while enabling the host device to move between access devices
Data Source
AI summary
A network system based on a SDN with a seamless handover mechanism, an operation method and a control apparatus thereof are provided. The network system includes network devices, host devices and a control apparatus. The network devices are connected together. A part of the network devices are equipped with wireless access networks of the same SSID, and each of the host devices is connected to one of the network devices. The control apparatus is connected to the network devices. When a first host device of the host devices is changed to connect with a second network device from a first network device, the control apparatus controls the network devices to return an address resolution response packet to the first host device in response to an address resolution request packet transmitted from the first host device, so as to maintain an IP address of the first host device.