Distributed Virtual Network Controller Path Tracing and Multicast
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Solution Overview
Problem
Current techniques for managing virtual networks in cloud data centers face challenges in determining physical network paths for packet flows, especially in multi-path environments where multiple paths of equal cost exist, and in providing efficient multicast services without requiring multicast support in the underlying physical network.
Innovation Solution
A distributed virtual network controller system that uses flow trace packets with incrementally increasing TTL values to determine physical network paths and a virtual network controller that creates multicast trees within the virtual overlay network to facilitate efficient packet routing and multicast services without relying on multicast support in the underlying physical network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional routing protocols are used in multi-path environments, then routing decisions can be made, but determining the actual physical network path taken by packet flows becomes difficult or impossible
Solution Approach 1:
The patent introduces flow trace packets as an intermediary mechanism to carry path information through the network. These special packets traverse the same multi-path routing environment as regular traffic but include tracking fields that record the physical path taken, thereby mediating between the routing protocol and the path determination requirement
Solution Approach 2:
The system implements feedback by having receiving nodes send back flow trace response packets containing the recorded path information to the source node. This feedback loop enables the source to learn the actual physical path taken by its traffic flows despite using traditional routing protocols
2Productivity
If multicast services are implemented in virtual networks, then efficient packet distribution is achieved, but support for multicast in the underlying physical network is required
Solution Approach 1:
The virtual network controller acts as an intermediary that implements multicast functionality at the virtualization layer. It translates virtual multicast requests into unicast packet distributions over the physical network, thereby providing multicast services without requiring physical network multicast support
Solution Approach 2:
The patent moves the multicast functionality from the physical network dimension to the virtual network dimension. By implementing multicast in the overlay virtual network layer rather than relying on the underlying physical network layer, it enables multicast services without physical network modifications
3Measurement precision
If flow trace packets are sent through the network to determine physical paths, then accurate path information is obtained, but network bandwidth is consumed by these trace packets
Solution Approach 1:
The system uses partial action by sending flow trace packets only when path information is actually needed, rather than continuously monitoring all traffic. This on-demand approach obtains accurate path information when required while minimizing bandwidth consumption by avoiding constant trace packet transmission
Data Source
AI summary
In general, techniques are described for configuring and managing virtual networks. For example, a distributed virtual network controller is described that configures and manages an overlay network within a physical network formed by plurality of switches. A plurality of servers are interconnected by the switch fabric, each of the servers comprising an operating environment executing one or more virtual machines in communication via the overlay networks. The servers comprises a set of virtual switches that extends the overlay network as a virtual network to the operating environment of the virtual machines. The controller may instruct the servers and the virtual switches to perform various operations, such as determining a physical network path taken by packets of a network packet flow, determining latency through the network, re-routing traffic in the virtual network due to network events, replicating traffic for multicasting, providing multi-tenant services to support multiple virtual networks, monitoring and logging traffic characteristics within the virtual networks and other operations.