[Search for users] [Overall Top Noters] [List of all Conferences] [Download this site]

Conference netcad::hub_mgnt

Title:	DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:	Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:	NETCAD::COLELLADT

Created:	Wed Nov 13 1991
Last Modified:	Fri Jun 06 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	4455
Total number of notes:	16761

3040.0. "DEChub 90/HINOTE PROBLEM" by OHFS01::MCDUFF () Thu Dec 07 1995 11:08

    I am having problems with a HiNote Ultra connected to DEChub 90
    using a DECrepeater 90C.  The HiNote are using the XIRCOM IIps
    ethernet card.
    
    Only HiNotes have this problem.  Whenever they are connected to
    the 90C they experience hanging and disconnects.  If I move
    their drop to a DEMPR the problem goes away.
    
    The DEChub is using DECbridge 90 connected to a DELNI with 
    heartbeat disabled.  Any ideas??? I have posted this problem
    in DECPC_PORTABLES and they suggested I post here as well.
    
    This problem is at a Digital facility located in Novi, MI.(OHF)
    
    Thanks,
    
    
    Jenny McDuff
    DTN 471-5737

T.R	Title	User	Personal Name	Date	Lines
3040.1	Known problem	NETRIX::"[email protected]"	Steven Freke	`Thu Dec 07 1995 11:31`	20
	Jenny Hello there. It appears that you have fallen victim to the ol' analogue/digital phase lock loop problem. May sound like a likley story but here it is. The early 90 series repeater, the 90c being on of them implements what is known as digital phase lock loop circuitry. This prevents any packet that is generated by an analogue phase lock loop device from being passed. And yes, you guessed it, the xircom cards use the analogue phase lock loop circuitry, and so do the dempr's. The only solution is to use, a later series 90 repeater, such as the 90ts, or a dempr. If you would like to discus this further or it still makes no sense then drop me a mail. Kernel::frekes. Regards Steven Freke LAN Team UK CSC 833 3017 [Posted by WWW Notes gateway]
3040.2		NETCAD::DOODY	Michael Doody	`Thu Dec 07 1995 11:35`	4
	Also this is discussed in note #2906. md
3040.3		NPSS::JOHNSON	Mike J., Network Products Support	`Fri Dec 08 1995 08:38`	15
	Re: .1, I believe Steven was mislead, or at least someone overstated the case. There is no inoperability issue between devices solely because one uses analog based PLL's and the other uses a digital circuit. The actual issue is that some ethernet devices, most frequently low cost NICs, do not comply to the timing specifications of 802.3. We are not currently aware of any situation where "in spec" devices, regardless of their PLL technology, fail to communicate with each other. The issue that Steven alluded to, and what is discussed in greater detail in 2906, is that the analog based repeaters are more "tolerant" to out-of-spec devices (i.e. NICs) than are the digital PLL based repeaters. Please refer to 2906 for more detail. /mj