| 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 | 
    
    	Let me run this by you guys and see if it is legal.
    
    	I have a customer that has a DC500 and Gigaswitch connected
        together via DEFCN-BA and DEFGL-AA with DEFXM-AA.  This is
    	a SAS connection.  This link is working fine.  
    
    	He now wants to make another link between the two boxes via
    	DEFCN-EA and DEFGL-AA with DEFXS-AA.  This also will be a SAS
    	connection.
    
    	I want to know if this would be a valid configuration or not.  How
    	would this effect spanning tree, if it is valid?  I personally 
    	don't think this will work.  A co-worker recommended making the
    	first link into a DAS link and then leave it alone.  The second
    	link wouldn't be use.  The customer's objective is redundancy.
    
    	Any insight would be appreciated,
    
    	Phil D.
    
       
| T.R | Title | User | Personal Name | Date | Lines | 
|---|---|---|---|---|---|
| 1812.1 | both are legal | NOTAPC::LEVY | Thu Sep 21 1995 13:56 | 7 | |
|     Both configurations are valid. One offers redundancy at the PHY level
    (the dual-homing solution), the other at the datalink level (the
    separate SAS solution).
    
    The separate SAS solution is more robust (more of the functionality is
    redundant), but I think the recovery time might be longer because of
    spanning tree re-configuration time.
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