Medium Access Control (MAC) and Physical Layer (PHY) - CISE

4-June-07 P1901_PRO_016_r0
Note: If a master has pending downstream data for an Idle slave belonging to a service class different from
7, the master may automatically switch the status of this slave into Active and start giving it transmission
opportunities.
� Unregistered: An Unregistered slave is not explicitly managed by a master. However, the master is
constrained to regularly broadcast access frames to discover/recover Unregistered slaves. The maximum
transmission interval of these access frames is MAX_ACCESS_INTERVAL.
The HE should also turn Idle itself when it has no users or all its users are Idle during a period, in order to
reduce to the minimum the electromagnetic interference and the power consumption.
This requirement implies stopping all MAC activity when the whole network is idle except for the transmissions
of Access Frames and Active, Alive and TDR Polling Frames, which shall be made at least within the specified
intervals.
The HE shall switch to Active status, when any of these situations occurs:
• automatically, if it has data from service class different from 7 to transmit to any user,
• after sending an Active Polling Frame or a TDR Polling Frame, if any of its slaves (TDRs and/or CPEs)
replies affirmatively and
• after sending an Access Request Frame if any user replies to it, so that the Access Protocol process can
be started.
4.2.2 Slave side
4.2.2.1 CPE side
From a slave standpoint, a CPE can be in two different states: Registered or Unregistered (see Figure 28 )
� Unregistered: This is the initial state of a slave. An unregistered slave is only authorized to answer access
frames as required by the access protocol. When the access protocol process is completed and successful,
the slave enters the Registered state.
� Registered: The following specific requirements apply to this state:
o A Registered CPE shall never reply to access frames from its current master. It might reply to
access frames from another master if it wishes to change its current master.
o A Registered CPE shall not reply to an Active polling token if it has no need for network
resources.
o A Registered CPE that wishes to continue in that state shall always reply to an Alive polling
token.
o A Registered CPE which has not received any Alive polling token or Data token for more than
MAX_ALIVE_TOKENS*MAX_ALIVE POLL_INTERVAL shall enter the Unregistered state.
The counting of this time interval shall be initialized at the end of the last polling slot in which
the slave has asserted a SOT or at the reception of the last Data Token received by the
Registered slave, whichever is later.
Submission page 88 UPA-OPERA