Get router gateway network id

# get router gateway external gateway network id
ROUTER_ID=
openstack router show ${ROUTER_ID} -f value -c gateway_external_info | jq '.network_id' | sed 's/"//g'

# router namespace is named in the form of qrouter-<ROUTER-ID>
# snat namespace is named with snat-<ROUTER-ID>
# fip namespace is named with fip-<EXTERNAL-NETWORK-ID>

# dvr layout
# edge node
# qr <---> sg <---> sg

# dvr node
# rfp <---> fpr <---> fg