Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
95
Table 78:Topology Discovery Flags
The Topology Discovery Support flag signals that the node supports further Topology Discovery inquiries. This flag is set to
0 by the drive.
The Loop Position Valid flag indicates that multiple Node Identification Data records are reported in the order detected by a
Loop Position Report Primitive. The drive returns only a single Node Identification Data record and sets this flag to 0.

17.3.16 Report Port Speed Capabilities (RPSC)

The Report Port Speed Capabilities ELS provides a mechanism for a port to report its current and potential link operating
speeds. The response to the RPSC payload is an LS_ACC response which indicates speed capabilities and current operating
speeds of each port.
Table 79:RPSC payload
Table 80:RPSC ACC payload
The Speed Capabilities fields indicate that the drive is capable of 1Gb/sec, 2 Gb/sec, and 4 Gb/sec operations.
The Operating Speed fields indicate the port's current operating speed as follows: 8000h for 1Gb/sec, 4000h for 2 Gb/sec, or
2000h for 4 Gb/sec.
17.4 Common Fibre Channel Services
Common Fibre Channel Service Request uses the Common Transport (CT) Interface to communicate with FC Fabric Servers.
The CT interface provides several Information Units, (CT_IU)s, which provide the transport mechanism between service
requestors and their servers.
In CT_IU frames, the TYPE field in the frame header is set to 20h (Fibre Channel Service). R_CTL is either 02h (FC-4
Device_Data, Unsolicited Control) for a Request or 03h (FC-4 Device_Data, Solicited Control) for a Reply.
Each CT_IU payload starts with a 16 byte CT Header as shown in Table81.
Byte BIT Default
request
values
76543210
0 Reserved TDF 000h
Byte Item Size (Bytes)
0-3 Command Code = 7D000000h 4
Byte Item Size (Bytes)
0ACC Cmd Code = 02h 1
1Reserved = 0 1
2-3 Number of Entries = 0002h 2
4-5 Port 1 Speed Capabilities = E000h 2
6-7 Port 1 Operating Speed 2
8-9 Port 2 Speed Capabilities = E000h 2
10-11 Port 2 Operating Speed 2