Deploy Layer3 EVPN over SR MPLS [Ospf / iBGP] [PE-CE is OSPF] in Nexus 9300

Introduction

This document describes how to deploy/configure Layer3 EVPN over Segment Routing (SR) Multiprotocol Label Switching (MPLS) on Nexus 9300 products with PE-CE protocol as Open Shortest Path First (OSPF).

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

• Border Gateway Protocol (BGP)
• Open Shortest Path First (OSPF)
• L3VPN
• EVPN
• Segment Routing (SR)

Components Used

The information in this document is based on these software and hardware versions:

• SPINE Hardware - 93360YC-FX2 running with 9.3.(3)
• LEAF Hardware - 93240YC-FX2 running with 9.3.(3)
• CLIENT - 93216TC-FX2 (Host-1), Catlyst-3750 (Host-2)

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Background Information

MPLS L3VPN Recap

A VPN is:

• An IP-based network delivering private network services over a public infrastructure.

• A set of sites that are allowed to communicate with each other privately over the Internet or other public or private networks.

Conventional VPNs are created by the configuration of a full mesh of tunnels or permanent virtual circuits (PVCs) to all sites in a VPN. This type of VPN is not easy to maintain or expand, as adding a new site requires changing each edge device in the VPN.

MPLS-based VPNs are created in Layer 3 and are based on the peer model. The peer model enables the service provider and the customer to exchange Layer 3 routing information. The service provider relays the data between the customer sites without customer involvement.

MPLS VPNs are easier to manage and expand than conventional VPNs. When a new site is added to an MPLS VPN, only the edge router of the service provider that provides services to the customer site needs to be updated.

These are the components of the MPLS VPN:

• Provider (P) router- Router in the core of the provider network. PE routers run MPLS switching and do not attach VPN labels to routed packets. VPN labels are used to direct data packets to the correct private network or customer edge router.
  
  

• PE router- Router that attaches the VPN label to incoming packets based on the interface or subinterface on which they are received, and also attaches the MPLS core labels. A PE router attaches directly to a CE router.
  
  

• Customer (C) router- Router in the Internet service provider (ISP) or enterprise network.
  
  

• Customer Edge (CE) router- Edge router on the network of the ISP that connects to the PE router on the network. A CE router must interface with a PE router.

Overview of EVPN with L3VPN (MPLS SR)