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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

1040.0. "DECbridge90 Forwarding Database" by EWBV06::KASAHARA () Mon May 30 1994 10:40

Hi all,

I have a problem regarding TCP/IP communication on DECbridge 90.

   Configuration:
                          on DEChub 90
             +----+      +-----+-----+
             |VAX |      |DB90 |DR90T+------------+---------[]
	     +-+--+      +--+--+-----+        +---+-----------+
        []-----+------------+----[]           |SUN workstation|
                                              +---------------+
		
	VAX  : UCX V2.0
        DB90 : DECbridge 90 Firmware V3.1
	DR90T: DECrepeater 90T 
	SUN  : SunOS V4.1.1


   Problem Scenario:

   I attempted to connect from VAX to Sun workstation with using ucx 
   telnet command. If VAX(UCX) does not have a ARP entry for Sun workstation,
   it works fine. After a few minutes, If I try this operation again with 
   using this ARP entry, it does NOT work.

   Supplement:

   In case of no ARP entry, VAX(UCX) transmits ARP request packet on Ethernet
   broadcast, and the target-host(SUN) sends back ARP reply to VAX.
   In this time, DB90 can have each address on the Forwarding Database, and
   this connection is established correctly.

   Question:

   When DB90 doesn't have the address of Sun workstation on Forwarding
   database, Is the packet sending to Sun discarded on DB90?
   In other words, Does DB90 forward the unknown destination packet to 
   any segument, when DB90 doesn't have any forwarding database entry?

Thanks in advance.
Yoshifumi.
T.RTitleUserPersonal
Name		DateLines
1040.1Known feature (problem).CGOS01::DMARLOWEHave you been HUBbed lately?Mon May 30 1994 15:109
    This has been discussed many times.  The DB 90 will NOT forward
    unknown addresses through to the work group side.  It will only
    forward if the address is in the address table.  This means that
    all nodes in the workgroup side must broadcast at least once in
    the AGE OUT timer.  DECNET and LAT do this but TCP doesn't.
    
    Check other notes for some ideas.
    
    dave
1040.2More questionEWB977::HOSOINobuyuki Hosoi,TNSG/CSC/MCS-JapanTue May 31 1994 09:31228
1040.34678::SLAWRENCEMon Jun 06 1994 14:1914
    I don't recommend fooling with the Bridge to try to fix this; other
    than perhaps setting the bridge age to 0.
    
    It is much easier to configure the Sun workstation to do something
    (anything) that causes it to send a packet now and then.  There are
    lots of choices for this; among them:
    
    	Configure NTP (preferably client, since Sun clocks aren't that
            good).
    
        Turn on one or more of the BSD broadcast-based services:
    		rwho, rdate, ruptime
    
    As long as it isn't silent for too long, you'll be fine.
1040.4reply to 1040.2NPSS::RAUHALAThu Oct 13 1994 20:289
    The problem with "DEFINE BRIDGE FLOOD ENABLE" is that on power-up
    port 1 became disabled.  This causes forwarding to stop.

    There was also a problem with the "SET ALL" command.  Sometimes it
    would cause port 1 to become disabled.

    The fixes for these problems are in the new image:

    	NPSS::PUBLIC$DSK:[INTERCHANGE]DEWGB_V39.TSK