For the neutron ipsec-site-connection-update command you should use --peer-cidrs flag instead of --peer-cidr
neutron ipsec-site-connection-update <ipsec_service_connection_id> --peer-cidrs 10.10.20.1/24
For the neutron ipsec-site- connection- update command you should use --peer-cidrs flag instead of --peer-cidr
neutron ipsec-site- connection- update <ipsec_ service_ connection_ id> --peer-cidrs 10.10.20.1/24