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- .. SPDX-License-Identifier: GPL-2.0
- =====================================================
- Notes on the DEC FDDIcontroller 700 (DEFZA-xx) driver
- =====================================================
- :Version: v.1.1.4
- DEC FDDIcontroller 700 is DEC's first-generation TURBOchannel FDDI
- network card, designed in 1990 specifically for the DECstation 5000
- model 200 workstation. The board is a single attachment station and
- it was manufactured in two variations, both of which are supported.
- First is the SAS MMF DEFZA-AA option, the original design implementing
- the standard MMF-PMD, however with a pair of ST connectors rather than
- the usual MIC connector. The other one is the SAS ThinWire/STP DEFZA-CA
- option, denoted 700-C, with the network medium selectable by a switch
- between the DEC proprietary ThinWire-PMD using a BNC connector and the
- standard STP-PMD using a DE-9F connector. This option can interface to
- a DECconcentrator 500 device and, in the case of the STP-PMD, also other
- FDDI equipment and was designed to make it easier to transition from
- existing IEEE 802.3 10BASE2 Ethernet and IEEE 802.5 Token Ring networks
- by providing means to reuse existing cabling.
- This driver handles any number of cards installed in a single system.
- They get fddi0, fddi1, etc. interface names assigned in the order of
- increasing TURBOchannel slot numbers.
- The board only supports DMA on the receive side. Transmission involves
- the use of PIO. As a result under a heavy transmission load there will
- be a significant impact on system performance.
- The board supports a 64-entry CAM for matching destination addresses.
- Two entries are preoccupied by the Directed Beacon and Ring Purger
- multicast addresses and the rest is used as a multicast filter. An
- all-multi mode is also supported for LLC frames and it is used if
- requested explicitly or if the CAM overflows. The promiscuous mode
- supports separate enables for LLC and SMT frames, but this driver
- doesn't support changing them individually.
- Known problems:
- None.
- To do:
- 5. MAC address change. The card does not support changing the Media
- Access Controller's address registers but a similar effect can be
- achieved by adding an alias to the CAM. There is no way to disable
- matching against the original address though.
- 7. Queueing incoming/outgoing SMT frames in the driver if the SMT
- receive/RMC transmit ring is full. (?)
- 8. Retrieving/reporting FDDI/SNMP stats.
- Both success and failure reports are welcome.
- Maciej W. Rozycki <macro@orcam.me.uk>
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