L2 Switch Snooping Control Plane Protocol Packets for L3 Information
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for a Layer 2 (L2) switch in a packet-switched network are inadequate for learning Layer 3 (L3) information about connected IP speakers without becoming visible at the IP layer, as they often require L3 information, assume network configurations, or necessitate the querier to be an IP speaker.
Innovation Solution
A method where a L2 switch configures itself to snoop control packets of a predetermined control plane protocol, extracting L3 information from snooped packets based on known L2 information, while remaining invisible at the IP layer by using techniques like broadcasting and filtering responses to discover IP addresses of connected devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If existing methods (ARP, DNS, OSPF, IS-IS, RIP) are used to obtain L3 information, then L3 information can be obtained, but the L2 switch becomes visible at the L3 layer or requires complex configuration
Solution Approach 1:
The patent uses control plane protocol packets as an intermediary mechanism. The L2 switch snoops these packets which already contain both L2 and L3 information, avoiding the need for the L2 switch to actively participate in L3 protocols or become visible at the L3 layer. This intermediary approach extracts L3 information from existing control traffic without requiring the L2 switch to speak L3 protocols.
Solution Approach 2:
The L2 switch autonomously extracts L3 information from snooped control plane packets without requiring manual configuration by network administrators. The switch independently identifies control plane packets, extracts the embedded L2-L3 mapping information, and builds its forwarding table automatically, eliminating the need for external configuration services.
2Loss of information
If L2 switch actively participates in L3 protocols to learn IP addresses, then L3 information can be obtained, but the switch can no longer remain invisible at the IP layer
Solution Approach 1:
Control plane protocol packets serve as an intermediary that carries both L2 and L3 information. The L2 switch passively snoops these packets and extracts the embedded L2-L3 mappings without needing to participate in L3 protocol exchanges. This allows the switch to learn IP addresses while maintaining its L2-only operational mode and remaining invisible to the L3 network.
Solution Approach 2:
The control plane protocol packets are pre-configured with both L2 and L3 information embedded within them. By snooping these pre-prepared packets, the L2 switch obtains L3 information without needing to perform L3 protocol actions itself, thus maintaining L2 invisibility while still learning IP addresses.
3Loss of information
If L2 switch uses existing L2-to-L3 methods, then L3 information can be obtained, but it requires the querier to be an IP speaker which L2 switches are not
Solution Approach 1:
The patent uses control plane protocol packets as an intermediary that bridges L2 and L3 information. These packets are generated by L3-speaking devices but contain L2 addressing information that the L2 switch can read. The L2 switch extracts L3 information from these intermediary packets without needing to speak L3 protocols itself, thus resolving the role compatibility issue.
Solution Approach 2:
The L2 switch extracts and copies L3 information from the control plane protocol packets without needing to originate or speak L3 protocols. By copying the L2-L3 mappings from existing control traffic, the switch obtains L3 information while maintaining its L2-only role in the network.
Data Source
AI summary
Measures for processing data in a packet-switched network. A first device is configured to snoop control packets of a predetermined control plane protocol in the network. The predetermined control plane protocol is operated by a plurality of other devices in the network to obtain Layer 2 information on the basis of known Layer 3 information. The first device does not operate the predetermined control plane protocol in the network. At the first device, in response to identifying that a given snooped packet was generated according to the predetermined control plane protocol. Layer 3 information associated with a second device in the plurality is extracted from the given snooped control plane protocol packet on the basis of known Layer 2 information associated with the second device. The second device is connected to the first device.