Hello, everyone!
This post describes the concepts and technologies of network virtualization.
Drives Network Virtualization Development
Computing virtualization technology drives the development of network virtualization. In a traditional data center, a server runs an operating system (OS), connects to a switch through physical cables, and implements data exchange with different hosts, traffic control, and security control using the switch. Upon completion of virtualization, one server is converted into multiple virtual hosts, and each virtual host has its own CPU, memory, and network interface card (NIC). It is important for virtual hosts located on a single server to maintain communication. The sharing of physical equipment has revealed a greater need for new security isolation and traffic control. Therefore, requirements for the virtual switching technology are heightened.
DVSs are introduced to unify and simplify the configuration and management of virtual switches on hosts. DVSs can be used to configure, manage, and monitor the virtual switches of multiple servers in a unified manner, and ensure network configuration consistency when VMs are migrated between servers.
Linux Bridge Introduction
A Linux bridge is a virtual network device that works at Layer 2 and functions as a physical switch.
A bridge can bind other Linux network devices as slave devices and virtualize these devices as ports. When a slave device is bound to a bridge, a switch port on the real network is connected to a network cable connected to a terminal.
Bridge device br0 is bound to actual device eth0 and virtual devices tap0 and tap1.
Only br0 is interconnected with the upper layer of the hypervisor network protocol stack. When receiving packets, slave devices send the packets to br0. br0 forwards the packets based on the mapping between the MAC address and the port.
OVS introduction
Open vSwitch (OVS) is a software-based open source virtual Ethernet switch.
The OVS supports multiple standard management interfaces and protocols and supports a distributed environment across multiple physical servers.
The OVS provides support for the OpenFlow protocol and can be integrated with multiple open source virtualization platforms.
It transmits traffic between VMs and allows VMs to communicate with external networks.
OVS is an open-source virtual switch based on software. It complies with the Apache 2.0 license. The OVS supports multiple standard management interfaces and protocols, such as NetFlow, sampled flow (sFlow), switched port analyzer (SPAN), remote switched port analyzer (RSPAN), command line interface (CLI), Link
Aggregation Control Protocol (LACP), and 802.1ag. It also supports distributed environments across multiple physical servers (similar to VMware vSwitch or Cisco Nexus 1000V). The OVS provides support for the OpenFlow protocol and can be integrated with multiple open source virtualization platforms.
OpenFlow is a type of Software Defined Network (SDN) and was first proposed by Professor Nick McKeown of Stanford University in OpenFlow: enabling innovation in campus networks, a paper published at ACM Communications Review in April 2008. Its original purpose was to allow network researchers to experiment with innovative network architectures and protocols. Considering that network innovations needed to be verified on actual networks and network devices could be modified by network researchers, the researchers proposed the OpenFlow control and forwarding separation architecture, and separated the control logic from the network device. The researchers could then program the network device through a group of defined interfaces to implement new network protocol and topology architecture without modifying the network device.
For more details, see What is OVS?
DVS introduction
Each host connects to DVSs which function as physical switches. A DVS connects to VMs through virtual ports and connects to physical Ethernet adapters on hosts where VMs reside. Therefore, the host network can communicate with the VM network using DVSs. In addition, a DVS allows the network configurations of VMs to remain unchanged when the VMs are migrated across hosts.
For more details, see What is Distributed Virtual Switches(DVS)?
EVS introduction
The user-mode EVS is running on the host. The DPDK NIC management API and huge-page memory are used to improve the packet receiving and sending performance and processing capability of the physical NIC.
Based on the vhost-user technology, the vhost interacts with the EVS in user mode and obtains the DPDK huge page address through address offset. The performance is improved by 30% to 40%.
Batch processing and polling mechanisms are used to improve the packet processing capability.
In the future, the ivshmem technology will be used to to communicate_with VMs using_its shared memory function for even better performance.
For more details, see Description Elastic Volume Service (EVS).
Huawei Distributed Switching Solution
Solution features:
Centralized management: Unified portal and centralized management simplify user management and configuration.
Open-source Open vSwitch: The open-source Open vSwitch is integrated to fully utilize and integrate virtual switching capabilities developed by open source communities.
A range of virtual switching layer-2 features, including switching, QoS, and security isolation, are provided.
Huawei DVS supports the virtual switching function based on software, which is developed based on the Open vSwitch architecture and the virtual switching function of a SR-IOV intelligent NIC (iNIC).
Although virtual switching functions of an open vSwitch and an iNIC are completely the same, the DVS Manager (DVSM) manages them using different plug-ins.
Virtual Switching Model
The process of configuring VM port attributes can be simplified by configuring attributes, including security and QoS, for a port group. The port group attributes setting has no impact on the proper running of VMs.
A port group consists of multiple ports with the same attributes. The VM port attributes setting can be simplified by configuring port group attributes, including bandwidth QoS, layer-2 security attributes, and VLAN. Port group attribute changes do not affect the operation of VMs.
An uplink connects the host and the DVS. Administrators can query information about an uplink, including its name, rate, mode, and status.
Uplink aggregation allows multiple physical ports on a server to be bound as one port to connect to VMs. Administrators can set the bound port to load balancing mode or active/standby mode.
That's all, thanks!
