IEEE 802.3z Gigabit Ethernet Task Force
September 9-11, 1996 Interim Meeting
Coeur d'Alene Inn and Conference Center
Coeur d'Alene, Idaho
Richard Taborek, Amdahl
TEST/MAINTENANCE/OFFLINE MODE PROPOSAL

                  TEST/MAINTENANCE/OFFLINE MODE PROPOSAL
                  ______________________________________

The inclusion of a Test/Maintenance/Offline mode has been suggested for
Gigabit Ethernet. This proposal defines support for this mode via the
existing Link_Startup protocol and a new Config_Register  bit.

o The proposed mode is called Offline.
o The Offline protocol proposed here provides the following functions:
  - Allows the implementation of a Test or Diagnostic mode;
  - Allows the port at one end of a link to provide notification to the
    attached port to avoid recognizing link errors or link failure;
  - Allows a port to be gracefully powered off by providing a
    recognizable indication prior to exhibiting loss of signal;
  - Allows a port to be removed from the active configuration;
  - Provides indication of internal PHY failure or Remote Fault.

CONFIG_REGISTER
_______________

+------------------------------------------------------+
|D0 |D1|D2|D3|D4|D5|D6|D7|D8|D9|D10|D11|D12|D13|D14|D15|
|OFF|  |  |  |  |FD|HD|  |  |  |  |  |  |  | RF|ACK| NP|
+------------------------------------------------------+
                
Config_Register bit usage:
--------------------------
D0/OFF:		  Offline mode
D5/A0:        Full Duplex capable
D6/A1:        Half Duplex capable
D13/RF:       Remote Fault
D14/ACK:      Acknowledge
D15/NP:       Next Page (Escape)

o The Offline_mode bit has the highest priority of all Config_Register
bits.
  - If Offline_mode is specified, all other Config_Reg bits, with the
    exception of Remote Fault, are ignored.

OFFLINE SIGNALING
_________________

o Offline is signaled to indicate any of the following conditions:
  - The transmitting port is powering off;
  - The transmitting port is indicating an error condition;
  - The transmitting port is entering the Offline state.
    + A port enters the Offline state in order to perform diagnostics
      or simply remain inactive.
    + To exit the Offline state, a port performs the Link Startup
      protocol.
o A port transmits the Offline indication for a specified (related to
maximum link length) minimum period of time before further actions are
taken.
  - Offline is indicated by initiating the Link_Startup protocol with
    the Offline mode bit set in the Config_Reg.
  - To exit the Offline state, a port performs the Link_Startup protocol. 

LINK_STARTUP PROCEDURE
______________________
 
figure missing, see PDF file
                                                                         
POWER-ON PROCEDURE - ONE PORT POWERS ON FIRST
_____________________________________________
 
figure missing, see PDF file
                                                                         
POWER-ON PROCEDURE - BOTH PORTS POWER ON SIMULTANEOUSLY
_______________________________________________________
 
figure missing, see PDF file
                                                                         
POWER-OFF PROCEDURE - ONE PORT POWERS OFF
_________________________________________
 
figure missing, see PDF file
                                                                         
DIAGNOSTIC PROCEDURE - ONE PORT RUNS DIAGNOSTICS
________________________________________________
 
figure missing, see PDF file
                                                                         
DIAGNOSTICS
___________

o Gigabit Ethernet PMA and PMD levels do not detect transmit code
  violations, invalid ordered sets, or any other alterations of the
  encoded bit stream.
  - Individual implementations may wish to transmit such invalid bit
    streams to provide diagnostic capability at the higher levels.
o Any transmission violation, such as invalid ordered sets, which follow
  valid character encoding rules are transparent to the PMA and PMD and
  will cause no difficulties.
o A limited set of diagnostic functions may be optionally specified for
  testing of the transmitter function of the port.
  - A typical diagnostic function is the ability to transmit invalid
    transmission characters within an otherwise valid bit stream.
  - Certain invalid bit streams may cause a receiver to lose word and/or
    bit synchronization.
  - Some diagnostic functions are intended for component testing and not
    for test to be performed at the customer site on a shippable or
    production adapter.
    
RANDOM JITTER TESTING
_____________________

o An example diagnostic function is one for transmitter random jitter
  testing:
  - In order to test the FC-0 transmitter for random jitter, a compliant
    transmitter has to be capable of transmitting the following two test
    patterns:
    a) A continuous sequence of D21.5 data bytes. This constitutes an
       alternating sequence of ones and zeros.
    b) A continuous sequence of K28.7 special characters. This
       constitutes an alternating sequence of five ones and five zeros.
o These patterns may be implemented at a bit or character level. They
are to be used for transmitter testing only. The receiver may not have
the capability to accept these diagnostic sequences.