Understanding Underlay Management
A private cloud data center is a critical business infrastructure that enterprise customers and service
providers need. These private cloud data centers help deliver automated application networking services
to internal departments. Today, most enterprises and service providers are moving from a vendor proprietary
fabric to a standard-based EVPN-VXLAN data center built on IP Clos technology. In an EVPN-VXLAN data
center, the underlay network is the physical infrastructure (switches, routers, firewall) on which overlay
network services are built.
An EVPN-VXLAN data center fabric relies on a standard model that consists of tenants. These tenants are
a group of endpoints, where,
•groups are subnets that are routed to other groups.
•endpoints are bridged within a group.
•tenants are routed to other tenants depending on the overlay architecture.
•tenants, groups, and endpoints may have services such as security, transit, multihoming, and QoS
associated with them.
•tenants and groups are implemented in the network as IP and Ethernet Virtual Private Networks (VPNs)
and Virtual Tunnel End Points (VTEPs).
EVPN-VXLAN is used in a data center fabric to deliver multi-tenant networking services. The following
network virtualization overlay architectures can be deployed in an EVPN-VXLAN IP fabric.
•Centrally-Routed Bridging overlay design—inter-VN routing occurs in either the spine switch or border
leaf switch.
•Edge-Routed Bridging overlay design— inter-VN routing occurs natively in the leaf switch that workloads
and servers are attached to.
•Ethernet overlays—Layer 2 reachability and workload mobility across endpoints are the main services
that the data center fabric provides.
•IP overlay—traffic in a tenant is routed using IP routes.
Contrail Networking Release 5.0.1 supports the automation and management of EVPN-VXLAN data center
IP fabric as well as the automation of layer 2 and layer 3 multi-tenant services on the IP fabric. The existing
Contrail Networking configuration node can provide intent driven automation capabilities on physical
network elements such as ToR and EoR switches, Spines, SDN gateway, and VPN gateways in the data
center. In addition, you can perform basic device management functions such as image upgrade, device
discovery, device underlay configuration, assigning roles to devices, and viewing node profile information
from the node.
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