Network Controller Packet Tracing for Virtualized Network Troubleshooting
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Solution Overview
Problem
In virtualized networks, troubleshooting is challenging due to tunneled packets passing through unmanaged physical forwarding elements with minimal processing, making it difficult for administrators to diagnose delivery issues.
Innovation Solution
A network controller is introduced to perform packet tracing operations by generating a traceable packet with specified source and destination addresses, inserting it into a managed forwarding element, and receiving observations to generate a report on the packet's journey, allowing administrators to track packet delivery and operations within the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If tunneled packets are used to transmit data across physical networks in virtualized environments, then network efficiency and packet delivery speed are improved, but the ability to troubleshoot and monitor packet operations deteriorates because unmanaged physical forwarding elements process packets with minimal intervention
Solution Approach 1:
The patent introduces a network controller as an intermediary between the managed forwarding elements and unmanaged physical forwarding elements. The controller receives packet trace requests, generates traceable packets with special markers, and receives observations from managed forwarding elements about the traced packets' journey through the network. This mediator enables monitoring and troubleshooting of tunneled packets without disrupting the high-speed packet delivery through unmanaged elements.
Solution Approach 2:
The patent implements a feedback mechanism where managed forwarding elements send observations back to the network controller about traced packets. These observations include information about packet forwarding decisions, tunnel selections, and delivery status. The controller uses this feedback to generate comprehensive trace reports, enabling administrators to monitor and diagnose network issues while maintaining efficient packet transmission through unmanaged elements.
2Device complexity
If unmanaged physical forwarding elements are used to forward tunneled packets, then device complexity and network management overhead are reduced, but troubleshooting capability and diagnostic information availability worsen
Solution Approach 1:
The patent segments the network control function by distinguishing between managed forwarding elements (with full control and observation capabilities) and unmanaged physical forwarding elements (simple packet forwarders). This segmentation allows unmanaged elements to operate with minimal complexity while managed elements and the network controller collect comprehensive troubleshooting information. The segmentation enables simplified packet forwarding through unmanaged elements while preserving diagnostic capabilities through managed elements.
3Difficulty of detecting and measuring
If packet tracing is implemented in virtualized networks with multiple logical networks over physical infrastructure, then network diagnostics and troubleshooting are improved, but device complexity and control system requirements increase
Solution Approach 1:
The network controller serves multiple functions: it manages forwarding elements, generates traceable packets, receives observations from managed elements, and produces trace reports. This universal controller handles packet tracing across multiple logical networks sharing the same physical infrastructure, enabling comprehensive diagnostics without requiring separate control systems for each logical network, thereby managing complexity through consolidation rather than proliferation of control functions.
Data Source
AI summary
Some embodiments provide a method for a network controller that manages several managed forwarding elements. The method receives a request to trace a specified packet having a particular source on a logical switching element. The method generates the packet at the network controller according to the packet specification. The generated packet includes an indicator that the packet is for a trace operation. The method inserts the packet into a managed forwarding element associated with the particular source. The method receives a set of messages from a set of managed forwarding elements that process the packet regarding operations performed on the packet.