Control Packet Management for Logical Network Tunnels
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Solution Overview
Problem
In datacenters, BFD packets and other control packets consume bandwidth and processing resources, impacting production traffic as the network scales, necessitating better management techniques to optimize control packet usage.
Innovation Solution
A network manager receives monitoring configuration data to specify control packet usage for logical datapaths and maps these to tunnels between host computers, configuring control packet modules to generate BFD packets based on the specified rates, with tunnel deduplication to eliminate unnecessary packet generation and exchanges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control packets (BFD packets) are generated for every logical datapath to monitor tunnel status, then tunnel monitoring reliability is improved, but network bandwidth and processing resources are excessively consumed
Solution Approach 1:
Multiple logical datapaths that map to the same physical tunnel share a single control packet instance. The network manager identifies when multiple logical datapaths use the same tunnel endpoints and consolidates their control packet requirements, so that one control packet monitors the tunnel for all shared logical datapaths rather than generating separate control packets for each logical datapath.
Solution Approach 2:
A single control packet serves multiple logical datapaths simultaneously by monitoring the underlying physical tunnel that carries traffic for all of them. The control packet module is configured to generate control packets based on the maximum rate requirement among all logical datapaths sharing the same tunnel, making the control packet mechanism universal across multiple logical connections.
2Measurement precision
If control packet generation rate is increased to meet minimum required rates for all logical datapaths, then monitoring precision is improved, but unnecessary packet generation increases resource consumption
Solution Approach 1:
The network manager determines the maximum control packet rate among all logical datapaths that share the same tunnel and configures the control packet module to generate packets at this consolidated rate. This parameter adjustment ensures that monitoring precision requirements for all logical datapaths are met while avoiding the resource waste of generating packets at higher rates that would satisfy the most demanding single datapath but exceed requirements for others.
3Productivity
If tunnel deduplication is implemented to eliminate unnecessary control packet generation, then resource efficiency is improved, but system complexity increases due to mapping and configuration management
Solution Approach 1:
The network manager acts as an intermediary between the logical datapath configuration and the control packet generation mechanism. It receives logical datapath information, performs tunnel mapping to identify which logical datapaths share the same physical tunnel, and configures the control packet module accordingly. This intermediary layer abstracts the complexity of deduplication logic from the control packet generation process itself.
Solution Approach 2:
The network manager performs tunnel mapping and identifies duplicate control packet requirements before control packet generation begins. By pre-processing the logical datapath configurations and determining which tunnels are shared, the system avoids generating redundant control packets from the outset, making the deduplication efficient and the complexity manageable through upfront analysis.
Data Source
AI summary
Some embodiments provide a method for managing control packet usage within a physical network that implements a plurality of logical networks. The method receives a tunnel monitoring configuration for a logical network. The configuration specifies control packet usage for logical datapaths between logical ports of the logical network. The method maps the logical datapaths to tunnels between host computers that host data compute nodes (DCNs) corresponding to the logical ports. Based on the mappings, the method configures control packet modules executing on the host computers to generate control packets for monitoring the tunnels based on the specified control packet usage.