LAN SDN technology hard core insider 11 the key of cloud convergence CP -- hierarchical port binding

In the previous post , We mentioned ,EVPN Is the matchmaker of cloud network integration , Match the cloud platform and network forwarding plane . And when the Hardware switch support EVPN and VXLAN when , It can replace software OVS, Improve network throughput , Reduce forwarding delay , And save valuable CPU resources .

There's a problem ：

Implement in hardware switch VXLAN In the encapsulated scene , It needs to be different VLAN Encapsulate to the corresponding VXLAN in .VLAN and VXLAN Correspondence of , yes Neutron Assigned , that ,Neutron How can we send this correspondence to the hardware switch ？

Let's uncover today's theme —— Hierarchical port binding .

Hierarchical port binding is in OpenStack Kilo Version of .

original , stay Neutron in , Distribute the configured components to the network nodes , be called ML2 Components . When the user Nova When you create a virtual machine in ,Nova Will inform Neutron Connect the network port of the virtual machine , Bound to the virtualized network . For Software Overlay Scene ,ML2 Component calls OVS The driver ——Mechanism Driver, Put the virtual machine VLAN、 Corresponding VXLAN Wait for the information to be configured to OVS On .

After introducing the hierarchical port binding mechanism ,ML2 Allow registration of multiple Mechanism Driver. such , Manufacturers of hardware switches only need to follow ML2 Mechanism Driver The statute of , Self developed switch Mechanism Driver And in ML2 Register in , You can take over the function of port binding , take Neutron The configuration of the virtualized network is taken over to the hardware switch .

The typical hierarchical port binding mechanism is shown in the figure below ：

The steps represented by numbers in the figure are as follows ：

The user is in Nova Create a virtual machine in , Join it to the network VXLAN 100;

Neutron by VXLAN 100 Create a network interface , And send the request to ML2 Components ;

ML2 Call the physical switch (TOR) Of Mechanism Driver, Set up VXLAN 100;

Physical switches Mechanism Driver Apply for another VLAN 110, notice ML2, Now this VM The network interface of also needs to be bound in VLAN 110

Physical switches Mechanism Driver adopt Netconf Interface setting VLAN 110 and VXLAN 100 The mapping relation of ;

ML2 call OVS Of Mechanism Driver, stay OVS add to VLAN 110, And put the VLAN Configuration to VM On the corresponding interface ,

OVS Will be right VM The sent packet is marked VLAN 110 Of TAG And forward to the interface of the physical switch , The physical switch will have VLAN 110 TAG Data envelop loading VXLAN 110;

We see ,VM A network interface of , Both through OVS Of Mechanism Driver Bound to OVS Of VLAN On the interface , And through the physical switch Mechanism Driver Bound to the physical switch VLAN/VXLAN On the interface ( On the switch, it is also called VXLAN Attach Circult Interface and VXLAN Tunnel Interface ). That's what's called “ Hierarchical port binding ” The meaning of this phrase .

The essence of hierarchical port binding , yes Neutron It provides an implementation hardware for hardware switch manufacturers SDN Overlay The interface of . With this mechanism , Cloud platform and physical network can become a pair of intimate CP.

A similar interface is LBaaS and FWaaS, It will be mentioned later .

In the next chapter, we will explain the hardware Overlay Forwarding plane principle of .