This is a demo config that I did to set up BGP between cumulus routers. I was having issues trying being able to ping a advertised network from BGP2 over to BGP1. The network was advertising correctly but i just was not able to ping from BGP1 to the interface on BGP2. After a while I found that i needed to advertise an interface on BGP1 so that BGP2 would know where to send back the reply.
BGP2
cumulus@cumulus:~$ sudo cat /etc/network/interfaces
source /etc/network/interfaces.d/*.intf
auto eth0
iface eth0 inet dhcp
auto swp1
iface swp1
bridge-vids 10
bridge-stp on
auto swp3
iface swp3
auto swp5
iface swp5
auto bridge
iface bridge
bridge-vlan-aware yes
bridge-ports swp1 swp3 swp5
bridge-vids 10 300
bridge-pvid 1
bridge-stp on
auto bridge.10
iface bridge.10
address 110.10.10.253/24
auto bridge.300
iface bridge.300
address 130.100.100.253/24
auto bridge.500
iface bridge.500
address 150.100.100.254/24
cumulus@cumulus:~$ sudo cat /etc/frr/frr.conf
router bgp 65101
bgp router-id 150.100.100.254
neighbor 110.10.10.254 remote-as external
neighbor 130.100.100.254 remote-as 65103
address-family ipv4 unicast
network 150.100.100.0/24
exit-address-family
cumulus@cumulus:~$
BGP4
cumulus@cumulus:~$ sudo cat /etc/network/interfaces
auto swp3
iface swp3
auto swp4
iface swp4
bridge-vids 400
bridge-stp on
auto bridge
iface bridge
bridge-vlan-aware yes
bridge-ports swp3 swp4
bridge-vids 300 400
bridge-pvid 1
bridge-stp on
auto bridge.300
iface bridge.300
address 130.100.100.254/24
auto bridge.400
iface bridge.400
address 140.100.100.254/24
cumulus@cumulus:~$ sudo cat /etc/frr/frr.conf
router bgp 65103
bgp router-id 140.100.100.254
neighbor 130.100.100.253 remote-as 65101
neighbor 140.100.100.253 remote-as 65102
cumulus@cumulus:~$
BGP3
cumulus@cumulus:~$ sudo cat /etc/network/interfaces
auto swp1
iface swp1
auto swp2
iface swp2
bridge-vids 100
bridge-stp on
auto swp4
iface swp4
bridge-vids 400
bridge-stp on
auto bridge
iface bridge
bridge-vlan-aware yes
bridge-ports swp2 swp4
bridge-vids 100 400
bridge-pvid 1
bridge-stp on
auto bridge.100
iface bridge.100
address 100.100.100.253/24
auto bridge.400
iface bridge.400
address 140.100.100.253/24
auto bridge.600
iface bridge.600
address 160.100.100.254/24
cumulus@cumulus:~$ sudo cat /etc/frr/fr
router bgp 65102
bgp router-id 160.100.100.254
neighbor 100.100.100.254 remote-as external
neighbor 140.100.100.254 remote-as 65103
address-family ipv4 unicast
network 140.100.100.0/24
network 160.100.100.0/24
exit-address-family
cumulus@cumulus:~$
BGP1
cumulus@cumulus:~$ sudo cat /etc/network/interfaces
auto swp1
iface swp1
bridge-vids 10
bridge-stp on
auto swp2
iface swp2
bridge-vids 100
bridge-stp on
auto bridge
iface bridge
bridge-vlan-aware yes
bridge-ports swp1 swp2
bridge-vids 10 100
bridge-pvid 1
bridge-stp on
auto bridge.10
iface bridge.10
address 110.10.10.254/24
auto bridge.100
iface bridge.100
address 100.100.100.254/24
cumulus@cumulus:~$ sudo cat /etc/frr/frr.conf
router bgp 65000
bgp router-id 100.100.100.254
neighbor 100.100.100.253 remote-as external
neighbor 110.10.10.253 remote-as external
address-family ipv4 unicast
network 100.100.100.0/24
exit-address-family
line vty
cumulus@cumulus:~$
