Recommended Service Network Plan
As mentioned previously, various application networks and servers are deployed in the production or service zones of most DCs, where the network configurations are complex, new services are provisioned, and current services are frequently scaled out. This leads to a high demand for network automation. As such, the following describes the SDN plan for DC zones.
When deploying an SDN DCN, the service network and management network should be planned separately. A service network carries service traffic and consists of nodes in four roles: server leaf, border leaf, service leaf, and spine.
Basic Principles for Designing a Physical Network
You are advised to use Huawei CloudEngine switches to build a spine-leaf structure on a DCN. The number of spine and leaf nodes can be flexibly configured based on the network scale. For details, see Figure 9.5.
1. Design of spine nodes
In the spine-leaf structure, the number of spine nodes depends on the oversubscription of leaf nodes, which varies depending on industries and customers.
Spine and leaf nodes are interconnected through Ethernet interfaces, which are configured to operate in Layer 3 routing mode in order to build an all-IP network.
2. Design of leaf nodes
It is recommended that two leaf nodes form a group, with each group using M-LAG active-active networking. If one leaf node is faulty, the other leaf node in the group is not affected, and service traffic is forwarded normally. In addition, an upgrade of devices in one group does not affect other groups.
FIGURE 9.5 Spine-leaf structure in a fabric network.
3. Design of forwarding
OSPF or BGP can be used for routing on the underlay network. Between spine and leaf nodes, IP ECMP paths can be created for load balancing. Through this approach, high bandwidth is available, traffic is forwarded without blocking, and faults are quickly converged. If any link fails, traffic is forwarded over other normal links, resulting in improved link reliability.