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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

452.0. "FDDI and maximum buffer size" by CSC32::D_RODRIGUEZ (Midnight Falcon ...) Fri Jan 17 1992 01:02

    
    A customer posed the following question:
    
    'Can you give me an example of how to set the maximum buffer size
    of the fddi controller?'  (It's not being used by decnet - he wants
    to do qio's to it.)
    
    I am not familiar at all with the fddi.  Any help is appreciated.
    
    Thanks,
    Dan

T.R	Title	User	Personal Name	Date	Lines
452.1	Answer for Phase IV on VMS	STAR::GAGNE	David Gagne - VMS/LAN Development	`Fri Jan 17 1992 09:31`	6
	On VMS running DECnet Phase IV, the FDDI drivers can handle transmission and reception of full size FDDI packets. However, DECnet treats the FDDI like an Ethernet because there's no logic to determine if the other node can handle a full size FDDI packet. So there is no mechanism on DECnet Phase IV on VMS to have DECnet use a full size FDDI packet.
452.2		NAC::THOMAS	The Code Warrior	`Fri Jan 17 1992 09:32`	5
	The maximum size for user data FDDI is 4478 (including LLC header). So this effectively means 4474 for LLC Class 2 4475 for LLC Class 1 4470 for SNAP SAP (including encapsulated Ethernet)
452.3	doc set	STAR::SALKEWICZ	It missed... therefore, I am	`Fri Jan 17 1992 14:24`	4
	For all of this kind of data, please refer to the V5.5 LAN Chapter in the IO User's guide Part II.
452.4		CSC32::D_RODRIGUEZ	Midnight Falcon ...	`Fri Jan 17 1992 15:51`	4
	Thanks to all... Dan
452.5	The Field has no 5.5 Docs yet	NOOKIE::JLYNCH	John Lynch, 339-5328, Greenbelt, MD	`Fri Feb 07 1992 17:07`	9
	Most of us don't have the 5.5 I/O users guide since it just began shipping to customers. The FT kit didn't include it. I'm also working on an FDDI performance problem. It sounds like DECnet cannot fully utilize the buffer size for FDDI. I assume direct QIO's to the driver can (for a DEMFA). thanks, (I'd rtfm, but i don't have the fm)
452.6	Summary of FDDI support on VMS	STAR::GAGNE	David Gagne - VMS/LAN Development	`Fri Feb 07 1992 18:15`	3
	Yes, the driver's support full size packets through all interfaces. And through QIO, the FC field is able to received and transmitted.
452.7	I/O Users Guide Ptr	DMEICE::PAGE		`Mon Feb 10 1992 08:23`	2
	Is the 5.5 I/O Users Guide available on-line? ...Cal
452.8	Don't use QIO interface ifor best performance	MSBCS::REGE		`Mon Feb 10 1992 10:31`	12
	Ref. 452.5 It is well known that QIO is worst interface from performance viewpoint. As I understand VCI or FFI are leaner interfaces and therefore are capable of delivering much higher application layer performance than QIO. David Gagne or Bill Salkewicz are the best people to comment on which one to use and why? Choose one of those if you can. /satish
452.9	FFI and VCI information	STAR::GAGNE	David Gagne - VMS/LAN Development	`Mon Feb 10 1992 13:36`	4
	FFI and VCI are interfaces that can only be used by products that ship on the VMS kit. So they are not available for third party vendors or customers. We plan on publicly documenting and supporting VCI. But for now, it is not available.