This article describes the issue of being unable to configure the bridge domain on M-series routers.
Unable to configure the bridge domain on M-series routers.
It is not possible to configure bridge domains on M-series routers. You can configure the bridge configuration only on MX-series routers. For more information, refer to the following link: http://www.juniper.net/techpubs/en_US/junos/topics/task/configuration/layer-2-services-bridge-domains-configuring-irb-for.html