Technical data

306 Appendix D Interfaces
Parameter:
In the link control frame, the parameter is used to transmit original information of the
individual link control frame and in the data frame, it is used for the relative offset.
 Header
The presence of the Optional Headers is indicated by the DF_CTL field. The treatment of the
Optional Headers with the AMS200 is shown in Table D.7.
Table D.7 Frame Format
No. Name Usage Treatment with the Disk Array Remarks
1 Expiration
Security
Header
Used to specify the expiration
time, etc. of the frame.
Ignores this header and processes the
command.
16 bytes
2 Network
Header
Used by a bridge or a gateway
node which interfaces to an
external Network.
Ignores this header and processes the
command.
16 bytes
3 Association
Header
Used to identify the process or
process group.
Ignores this header and processes the
command.
32 bytes
4 Device
Header
Used by the upper level protocol. Ignores this header and processes the
command.
16 bytes
32 bytes
64 bytes
The AMS200 does not add Optional Headers in a Data frame to be sent to other N_Ports.
The host computer shall not add Optional Headers in a frame sent to the AMS200.
If the Optional Headers are added in the Data frames sent to the subsystem, correct
operation in the AMS200 is not guaranteed.