Virtual Campus Network Architecture Overview
On a large or midsize campus network, the virtualization solution can be used to decouple services from the network, construct a multi-purpose network, and achieve flexible, fast service deployment without changing the basic network infrastructure. In this solution, the virtual campus network architecture poses requirements different from those on traditional network architecture. Figure 1-2 illustrates the virtual campus network architecture. The underlay is the physical network layer, and the overlay is the virtual network layer constructed on top of the underlay based on the Virtual Extensible LAN (VXLAN) technology.
The overlay consists of the fabric and VN.
- Fabric: a network with pooled resources abstracted from the underlay network. When creating an instantiated virtual network (VN), you can select the pooled network resources on the fabric.On a fabric network, VXLAN tunnel endpoints (VTEPs) are further divided into the following roles:
- Border: border node of the fabric network. It corresponds to a physical network device and provides data forwarding between the fabric and external networks. Generally, VXLAN-capable core switches function as border nodes.
- Edge: edge node of the fabric network, which corresponds to a physical network device. User traffic enters the fabric network from the edge node. Generally, VXLAN-capable access or aggregation switches are used as edge nodes.
- VN: logically isolated virtual network instances (VN 1 and VN 2 in the figure) that are constructed by instantiating a fabric. One VN corresponds to one isolated network (service network), for example, R&D network.
Table 1-1 lists the resource pools on a fabric and how to invoke these resources during VN creation.
Resource Pool on a Fabric |
How to Invoke Resources in a Resource Pool During VN Creation |
|---|---|
VN resource pool, which contains the number of VNs that can be created on an overlay. |
Each time a VN is created, a VN resource is used. |
VLAN resource pool, which is used in scenarios where terminals are connected to VNs and VNs communicate with external network resources. The VLAN resource pool is planned when configuring the fabric global resource pool. |
When creating a user gateway in a VN, you can select a resource from the fabric global resource pool to configure a user VLAN. |
BD/VNI resource pool, which is used when dividing Layer 2 broadcast domains in a VN and configuring corresponding VBDIF interfaces that function as the gateway interfaces of user subnets. The BD/VNI resource pool is planned when configuring the fabric global resource pool. |
When a user gateway is created in a VN, resources in the BD/VNI resource pool are automatically invoked to create a BD and the corresponding VBDIF interface. |
User access point resource pool, which is planned during access management configuration for a fabric. This resource pool includes the authentication modes that can be bound to access points. |
When configuring user access in a VN, you can select planned access point resources. |
Egress pool, which contains the external resources that can be used by VNs. Two types of external resources are created during fabric configuration:
|
When creating a VN, you can select external networks and network service resources. |