This lab show an ECMP (feature called RADIX_MPATH on FreeBSD) routing example using BSDRP (FreeBSD 11).

Here is the logical and physical view:

Download BSDRP serial image (prevent to have to use an X display) on Sourceforge.

More information on these BSDRP lab scripts available on How to build a BSDRP router lab.

Start the lab with 6 routers. With bhyve under FreeBSD:

user:~ # BSDRP-lab-bhyve.sh -i BSDRP.amd64/BSDRP-1.71-full-amd64-serial.img.xz -n 6
BSD Router Project (http://bsdrp.net) - bhyve full-meshed lab script
Setting-up a virtual lab with 6 VM(s):
- Working directory: /tmp/BSDRP
- Each VM have 1 core(s) and 256M RAM
- Switch mode: bridge + tap
- 0 LAN(s) between all VM
- Full mesh Ethernet links between each VM
VM 1 have the following NIC:
- vtnet0 connected to VM 2.
- vtnet1 connected to VM 3.
- vtnet2 connected to VM 4.
- vtnet3 connected to VM 5.
- vtnet4 connected to VM 6.
VM 2 have the following NIC:
- vtnet0 connected to VM 1.
- vtnet1 connected to VM 3.
- vtnet2 connected to VM 4.
- vtnet3 connected to VM 5.
- vtnet4 connected to VM 6.
VM 3 have the following NIC:
- vtnet0 connected to VM 1.
- vtnet1 connected to VM 2.
- vtnet2 connected to VM 4.
- vtnet3 connected to VM 5.
- vtnet4 connected to VM 6.
VM 4 have the following NIC:
- vtnet0 connected to VM 1.
- vtnet1 connected to VM 2.
- vtnet2 connected to VM 3.
- vtnet3 connected to VM 5.
- vtnet4 connected to VM 6.
VM 5 have the following NIC:
- vtnet0 connected to VM 1.
- vtnet1 connected to VM 2.
- vtnet2 connected to VM 3.
- vtnet3 connected to VM 4.
- vtnet4 connected to VM 6.
VM 6 have the following NIC:
- vtnet0 connected to VM 1.
- vtnet1 connected to VM 2.
- vtnet2 connected to VM 3.
- vtnet3 connected to VM 4.
- vtnet4 connected to VM 5.
For connecting to VM'serial console, you can use:
- VM 1 : cu -l /dev/nmdm1B
- VM 2 : cu -l /dev/nmdm2B
- VM 3 : cu -l /dev/nmdm3B
- VM 4 : cu -l /dev/nmdm4B
- VM 5 : cu -l /dev/nmdm5B
- VM 6 : cu -l /dev/nmdm6B

R1 is configured as a simple host with multiples aliases:

sysrc hostname=R1
sysrc gateway_enable=NO
sysrc ipv6_gateway_enable=NO
sysrc ifconfig_vtnet0="inet 10.0.12.1/24"
sysrc ifconfig_vtnet0_alias1="inet 10.0.12.11/32"
sysrc ifconfig_vtnet0_alias2="inet 10.0.12.21/32"
sysrc ifconfig_vtnet0_alias3="inet 10.0.12.31/32"
sysrc ifconfig_vtnet0_alias4="inet 10.0.12.41/32"
sysrc ifconfig_vtnet0_alias5="inet 10.0.12.51/32"
sysrc ifconfig_vtnet0_ipv6="inet6 2001:db8:12::1 prefixlen 64"
sysrc ifconfig_vtnet0_alias61="inet6 2001:db8:12::11 prefixlen 64"
sysrc ifconfig_vtnet0_alias62="inet6 2001:db8:12::21 prefixlen 64"
sysrc ifconfig_vtnet0_alias63="inet6 2001:db8:12::31 prefixlen 64"
sysrc ifconfig_vtnet0_alias64="inet6 2001:db8:12::41 prefixlen 64"
sysrc ifconfig_vtnet0_alias65="inet6 2001:db8:12::51 prefixlen 64"
sysrc defaultrouter="10.0.12.2"
sysrc ipv6_defaultrouter="2001:db8:12::2"
service hostname restart
service netif restart
service routing restart
config save

R2 is a router with ECMP: 2 static routes toward the same destination but using 2 different next-hop.

sysrc hostname=R2
sysrc ifconfig_vtnet0="inet 10.0.12.2/24"
sysrc ifconfig_vtnet1="inet 10.0.23.2/24"
sysrc ifconfig_vtnet2="inet 10.0.24.2/24"
sysrc ifconfig_vtnet0_ipv6="inet6 2001:db8:12::2 prefixlen 64"
sysrc ifconfig_vtnet1_ipv6="inet6 2001:db8:23::2 prefixlen 64"
sysrc ifconfig_vtnet2_ipv6="inet6 2001:db8:24::2 prefixlen 64"
sysrc static_routes="R3R6 R3R5 R4R6 R4R5"
sysrc route_R3R6="-net 10.0.56.0/24 10.0.23.3"
sysrc route_R3R5="-net 10.0.35.0/24 10.0.23.3"
sysrc route_R4R6="-net 10.0.56.0/24 10.0.24.4"
sysrc route_R4R5="-net 10.0.45.0/24 10.0.24.4"
sysrc ipv6_static_routes="R3R6 R3R5 R4R6 R4R5"
sysrc ipv6_route_R3R6="2001:db8:56:: -prefixlen 64 2001:db8:23::3"
sysrc ipv6_route_R3R5="2001:db8:35:: -prefixlen 64 2001:db8:23::3"
sysrc ipv6_route_R4R6="2001:db8:56:: -prefixlen 64 2001:db8:24::4"
sysrc ipv6_route_R4R5="2001:db8:45:: -prefixlen 64 2001:db8:24::4"
service hostname restart
service netif restart
service routing restart
config save

R3 is a simple router.

sysrc hostname=R3
sysrc ifconfig_vtnet1="inet 10.0.23.3/24"
sysrc ifconfig_vtnet3="inet 10.0.35.3/24"
sysrc ifconfig_vtnet1_ipv6="inet6 2001:db8:23::3 prefixlen 64"
sysrc ifconfig_vtnet3_ipv6="inet6 2001:db8:35::3 prefixlen 64"
sysrc static_routes="R6 R1"
sysrc route_R1="-net 10.0.12.0/24 10.0.23.2"
sysrc route_R6="-net 10.0.56.0/24 10.0.35.5"
sysrc ipv6_static_routes="R6 R1"
sysrc ipv6_route_R1="2001:db8:12:: -prefixlen 64 2001:db8:23::2"
sysrc ipv6_route_R6="2001:db8:56:: -prefixlen 64 2001:db8:35::5"
service hostname restart
service netif restart
service routing restart
config save

R4 is like R3, a simple router.

sysrc hostname=R4
sysrc ifconfig_vtnet1="inet 10.0.24.4/24"
sysrc ifconfig_vtnet3="inet 10.0.45.4/24"
sysrc ifconfig_vtnet1_ipv6="inet6 2001:db8:24::4 prefixlen 64"
sysrc ifconfig_vtnet3_ipv6="inet6 2001:db8:45::4 prefixlen 64"
sysrc static_routes="R6 R1"
sysrc route_R1="-net 10.0.12.0/24 10.0.24.2"
sysrc route_R6="-net 10.0.56.0/24 10.0.45.5"
sysrc ipv6_static_routes="R6 R1"
sysrc ipv6_route_R1="2001:db8:12:: -prefixlen 64 2001:db8:24::2"
sysrc ipv6_route_R6="2001:db8:56:: -prefixlen 64 2001:db8:45::5"
service hostname restart
service netif restart
service routing restart
config save

R5 is like R2, a router with ECMP: 2 static routing toward the same destination but using 2 different next-hop..

sysrc hostname=R5
sysrc ifconfig_vtnet2="inet 10.0.35.5/24"
sysrc ifconfig_vtnet3="inet 10.0.45.5/24"
sysrc ifconfig_vtnet4="inet 10.0.56.5/24"
sysrc ifconfig_vtnet2_ipv6="inet6 2001:db8:35::5 prefixlen 64"
sysrc ifconfig_vtnet3_ipv6="inet6 2001:db8:45::5 prefixlen 64"
sysrc ifconfig_vtnet4_ipv6="inet6 2001:db8:56::5 prefixlen 64"
sysrc static_routes="R3R1 R3R2 R4R1 R4R2"
sysrc route_R3R1="-net 10.0.12.0/24 10.0.35.3"
sysrc route_R3R2="-net 10.0.23.0/24 10.0.35.3"
sysrc route_R4R1="-net 10.0.12.0/24 10.0.45.4"
sysrc route_R4R2="-net 10.0.24.0/24 10.0.45.4"
sysrc ipv6_static_routes="R3R1 R3R2 R4R1 R4R2"
sysrc ipv6_route_R3R1="2001:db8:12:: -prefixlen 64 2001:db8:35::3"
sysrc ipv6_route_R3R2="2001:db8:23:: -prefixlen 64 2001:db8:35::3"
sysrc ipv6_route_R4R1="2001:db8:12:: -prefixlen 64 2001:db8:45::4"
sysrc ipv6_route_R4R2="2001:db8:24:: -prefixlen 64 2001:db8:45::4"
service hostname restart
service netif restart
service routing restart
config save

R6, like R1 is configured as a simple host with multiple aliases:

sysrc hostname=R6
sysrc gateway_enable=NO
sysrc ipv6_gateway_enable=NO
sysrc ifconfig_vtnet4="inet 10.0.56.6/24"
sysrc ifconfig_vtnet4_alias1="inet 10.0.56.16/32"
sysrc ifconfig_vtnet4_alias2="inet 10.0.56.26/32"
sysrc ifconfig_vtnet4_alias3="inet 10.0.56.36/32"
sysrc ifconfig_vtnet4_alias4="inet 10.0.56.46/32"
sysrc ifconfig_vtnet4_alias5="inet 10.0.56.56/32"
sysrc ifconfig_vtnet4_ipv6="inet6 2001:db8:56::6 prefixlen 64"
sysrc ifconfig_vtnet4_alias61="inet6 2001:db8:56::16 prefixlen 64"
sysrc ifconfig_vtnet4_alias62="inet6 2001:db8:56::26 prefixlen 64"
sysrc ifconfig_vtnet4_alias63="inet6 2001:db8:56::36 prefixlen 64"
sysrc ifconfig_vtnet4_alias64="inet6 2001:db8:56::46 prefixlen 64"
sysrc ifconfig_vtnet4_alias65="inet6 2001:db8:56::56 prefixlen 64"
sysrc defaultrouter="10.0.56.5"
sysrc ipv6_defaultrouter="2001:db8:56::5"
service hostname restart
service netif restart
service routing restart
config save

Flows from R1 to R6 should be load-balanced by R2 toward R3 and R4. Let's check using multiple sources and destination IP addresses: