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Conference 7.286::fddi

Title:	FDDI - The Next Generation

Moderator:	NETCAD::STEFANI

Created:	Thu Apr 27 1989
Last Modified:	Thu Jun 05 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	2259
Total number of notes:	8590

2255.0. "DEFPA-DB is SAS or DAS Mode?" by CSC32::A_LICAUSE () Tue May 20 1997 10:24

    It has always been my understanding that any DAS capable interface
    will also run in SAS mode....is this true for the DEFPA-DB on V4.0b
    dunix?
    
    A customer has asked and I figured I'd check with the experts before
    commiting to the answer.
    
    Thanks,
    Al

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2255.1 A DAS will work where a SAS works NETCAD::ROLKE The FDDI Genome Project Tue May 20 1997 13:49 22

T.R	Title	User	Personal Name	Date	Lines
2255.1	A DAS will work where a SAS works	NETCAD::ROLKE	The FDDI Genome Project	`Tue May 20 1997 13:49`	22
	Hi Al, A DAS interface is capable of attaching to either of the two logical ring in the FDDI dual ring; a SAS can only attach to one ring. This difference means that the DAS interface will survive a failure yet keep the ring going. The connection policy is that all connections are permitted except A to A, B to B, and M to M. If you have a SAS adapter it may connect to any type of peer. If you have a DAS adapter (A and B) then some connections, A-A and B-B, are not allowed. From 2172.1 the DEFPA-DB is a DAS adapter. It presents A and B ports to the network regardless of your operating system type. As such it may be used in virtually any place that a SAS adapter might go if you are careful with your cables. Recent firmware changes allow the DEFPA-DB adapter to run as SAC (single attach concentrator, with a single M and S port) but I don't think any driver exploits this capability. Chuck

Hi Al,

A DAS interface is capable of attaching to either of the two logical
ring in the FDDI dual ring; a SAS can only attach to one ring.  This
difference means that the DAS interface will survive a failure yet keep
the ring going.

The connection policy is that all connections are permitted except
A to A, B to B, and M to M.  If you have a SAS adapter it may connect
to any type of peer.  If you have a DAS adapter (A and B) then some
connections, A-A and B-B, are not allowed.

From 2172.1 the DEFPA-DB is a DAS adapter.  It presents A and B ports
to the network regardless of your operating system type.  As such it
may be used in virtually any place that a SAS adapter might go if you
are careful with your cables.

Recent firmware changes allow the DEFPA-DB adapter to run as SAC (single
attach concentrator, with a single M and S port) but I don't think any
driver exploits this capability.

Chuck