Conference azur::mcc

474.0. "BRIDGE AM forwarding db peculiarity?" by NWACES::OBRIEN () Tue Nov 13 1990 09:15

    I am running MCC Brisge AM using the following command:
        SHOW BRIDGE name FORWARDING DATA PHYSICAL ENTRY * ALL ATTRIBUTES,
        TO FILE=file.dat
    
    When I compare the results with the corresponding command output
    run using ELMS I find the following differences:
    	some stations present in the file generated by ELMS are missing
    	from the file generated by MCC
    
        some stations present in the file generated by ELMS get the
        following error message from MCC run:
    No such entity: BRIDGE NWACES_NS:.BLUE_GREEN FORWARDING DATABASE PHYSICAL ENTRY 
    08-00-2B-0E-6A-E8 
                         Unknown Entity = BRIDGE NWACES_NS:.BLUE_GREEN 
                                          FORWARDING DATABASE PHYSICAL ENTRY 
                                          08-00-2B-0E-6A-E8 
    
    Could someone please explain this behavior to me?
    
    Thanks, Ania
    

The Bridge's Forwarding Database is very *dynamic*: On a large XLAN, Physical
Entries (addresses) are continuously being added and aged out of it.

The "Unknown Entity" exception indicates that the Physical Entry was not in the
Forwarding Database when the Bridge was polled.

BTW, If you issue the DECmcc command twice, the lists will probably be
different (implications of this behavior on the ICONIC MAP PM is left as an
exercise for the reader).

						Chris

    Thanks for your reply and explanation. However our XLAN is not very
    large: 3 bridges and around 200 stations. What seems peculiar to me is
    that the actual bridge addresses are missing from the forwarding DBs
    in all cases that I have run. Is that still consistent with the
    'dynamic' feature of the Bridge AM?
    
    Thanks, Ania

    
    Chris Brienen and Ania have spoken about this off line. Ania is
    doing additional testing at this time and this discussion is now
    being continued off line.