This parameter defines if a port is used as a master or slave for port binding purposes. Only odd ports are configured masters for the binding feature. When the master is enabled, the master port will be bound with the next even port number. Binding two SHDSL ports together will aggregate their bandwidths together. This does not apply to HDSL2 modem technology. Other line configuration rules: 1) Port rate mode needs to be Fixed. 2) The master ports max-rate and rate-mode are used for both ports. 3) Both ports need to be enabled.