creates 2 connected namespaces vpp1 & vpp2

#!/bin/bash
	#
	# set up a network env with 2 namespaces:
	#
	# [ vpp1 ]------[vpp]------[ vpp2 ]
	#
	# vpp1: 192.168.0.1
	# vpp2: 192.168.0.2
	ip netns delete vpp1
	ip netns delete vpp2
	ip netns add vpp1
	ip netns add vpp2
	vppctl tap connect vpp1
	vppctl tap connect vpp2
	vppctl set interface state tap-0 up
	vppctl set interface state tap-1 up
	ip link set dev vpp1 netns vpp1
	ip link set dev vpp2 netns vpp2
	ip netns exec vpp1 ip link set vpp1 up
	ip netns exec vpp2 ip link set vpp2 up
	vppctl set interface l2 bridge tap-0 23
	vppctl set interface l2 bridge tap-1 23
	ip netns exec vpp1 ip addr add 192.168.0.1/24 dev vpp1
	ip netns exec vpp2 ip addr add 192.168.0.2/24 dev vpp2
	# smoke-test
	ip netns exec vpp1 ping -c1 192.168.0.2
	ip netns exec vpp2 ping -c1 192.168.0.1

https://www.slideshare.net/npsg/vpp-72218327