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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

3513.0. "netdesigner model 1/Model 2" by SIOG::M_CONNOLLY () Tue May 07 1996 07:53

    Hi,
    
    	Can anybody  give me a definitive answer to the following
    question. Having constructed a network using netdesigner, the
    configuration fails on the IEE802.3 Model 1 analysis, but passes
    on the IEEE802.3 Model 2 analysis. Have I got a network I can
    install and stand over or have I got an illegal configuration ?
    
    Thanks,
    
    	Mike.

T.R Title User Personal
Name Date Lines

3513.1 Hope this is not as basic�so you already knew it! MXOC00::CSILVA Carlos@MXO 7296514 Free but focused Tue May 07 1996 12:05 20

T.R	Title	User	Personal Name	Date	Lines
3513.1	Hope this is not as basic�so you already knew it!	MXOC00::CSILVA	Carlos@MXO 7296514 Free but focused	`Tue May 07 1996 12:05`	20
	The reason for Model 1 and Model 2 are historical. Initially when Ethernet networks were all coax, you can follow the single 5-4-3 rule (segments-repeaters-segements with nodes) that is Model 1. As new physical standards appeared (10-Base-T, 10-BaseF, a more sophsiticated method considering propagation delays was needed, so you have Model 2. If you design a network when the oposite points are more than 4 repeaters apart you are violating Model 1 and you don�t have a valid network design. If you take 5 fiber segments of 2Km each one connected by repeaters and 2 segments are for interconnection of repeaters you are following Model 1, but you don�t have a network you can trust on according to Model 2.

    
    
    The reason for Model 1 and Model 2 are historical.
    
    Initially when Ethernet networks were all coax, you can 
    follow the single 5-4-3 rule (segments-repeaters-segements with
    nodes) that is Model 1.
    
    As new physical standards appeared (10-Base-T, 10-BaseF, 
    a more sophsiticated method considering propagation delays 
    was needed, so you have Model 2.
    
    If you design a network when the oposite points are more
    than 4 repeaters apart you are violating Model 1 and you
    don�t have a valid network design.
    
    If you take 5 fiber segments of 2Km each one connected 
    by repeaters and 2 segments are for interconnection of
    repeaters you are following Model 1, but you don�t have
    a network you can trust on according to Model 2.