# File lib/openstack/network/connection.rb, line 61
    def create_subnet(network_id, cidr, ip_version="4", opts={})
      body_hash = {"subnet"=>{"network_id"=> network_id, "cidr"=>cidr, "ip_version"=>ip_version}}
      body_hash["subnet"].merge!(opts) #fixme - validation?
      req_body = JSON.generate(body_hash)
      response = @connection.req("POST", "/subnets", {:data=>req_body})
      OpenStack::Network::Subnet.new(JSON.parse(response.body)["subnet"])
    end