MPLS L3VPN on Linux
IP addressing:
Loopbacks ISP 10.255.1.0/24:
RR Lo0: 10.255.1.1/32
PE1 Lo0: 10.255.1.2/32
PE2 Lo0: 10.255.1.3/32
Loopbacks CE-A 10.100.255.0/24:
CE01-A Lo0: 10.100.255.1/32
CE02-A Lo0: 10.100.255.2/32
RR - PE1: 10.12.1.0/24
RR - PE2: 10.13.1.0/24
PE1 - CE01A: 10.24.1.0/24
PE2 - CE02A: 10.36.1.0/24
Prerequisites
Replace netplan with ifupdown (ifupdown2 if any vrf exist):
sudo apt install -y ifupdown && sudo apt purge -y netplan.io
Install FRR (will be acting as a routing daemon):
sudo apt install frr frr-pythontools
Turn system into a router:
Uncomment net.ipv4.ip_forward=1 in /etc/sysctl.conf
sysctl –p
Complete initial FRR setup: Enable required daemons and add service to startup (Refer to FRR routing daemon initial setup)