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Conference turris::digital_unix

Title:DIGITAL UNIX(FORMERLY KNOWN AS DEC OSF/1)
Notice:Welcome to the Digital UNIX Conference
Moderator:SMURF::DENHAM
Created:Thu Mar 16 1995
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:10068
Total number of notes:35879

8679.0. "?Dual rail Ethernet configuration??" by RICKS::OPP () Sun Feb 02 1997 22:50

    	I'd like to be able to configure and use two Ethernet adapters
    in a small (Alpha PC) Digital UNIX system for testing purposes.  
    In one test configuration, both adapters would be connected to the
    same Ethernet LAN segment using different IP addresses in the same
    IP subnet.  In another test configuration, each adapter would be 
    connected to an independent Ethernet "rail" and the IP addresses 
    are expected to be in differnet subnets, for example, 16.127.160.120
    and 16.127.161.120 with a subnet mask of 255.255.255.0.  Are there 
    any configuration steps required beyond those normally executed 
    (via netsetup or the CDE GUI equivalent) for a single adapter?  
    
    Thanks,
    
    Greg
T.RTitleUserPersonal
Name		DateLines
8679.1what do you expect to accomplish?NETRIX::"[email protected]"Farrell WoodsMon Feb 03 1997 10:4314
Having two adaptors on the same wire/subnet doesn't buy you anything.  Pakcets
can be addressed to either adaptor's IP address and of course will be picked
up by the appropriate adaptor and sent up the stack.  But IP will use *only*
the first adaptor configured for a given subnet when it sends packets.

The second scenario will work just fine, since you intend to put each adaptor
on its own subnet.

netconfig will let you set up as many adaptors as you like.


	-- Farrell

[Posted by WWW Notes gateway]
8679.2Buys half an adapterGREGOR::OPPMon Feb 03 1997 13:2011
    RE: .1
    
    	Well, it sounds like two adapters connected to the same rail 
    and within the same subnet does buy me � an adapter.  A true dual
    rail environment is the goal.  However, at the moment we're waiting
    for the network hardware to assemble the second rail.
    
    	Thank you for the technical advice,
    
    Greg
8679.3Still not clearNETRIX::"[email protected]"Dave CherkusMon Feb 03 1997 13:5014
It's still not clear what you want.  Are you trying to
increase performance, or availability?  If it's performance,
you will probably see a loss, because one controller alone can
saturate the wire, and running the second one will increase
the load on the system because both will generate interrupts
when broadcast messages arrive.

The whole theme of dual-rail comes up time and again.  I'm
wondering if the idea comes from some other environment where
dual rail is a win, or if comes from the idea that two has
to be better than one?

Dave
[Posted by WWW Notes gateway]
8679.4System Qual tests the limits, nes pas?GREGOR::OPPTue Feb 04 1997 12:5111
    RE: .3
    
    	In this case, it comes from "If a customer might build such
    a configuration, then we (Digital Semiconductor) had better test
    it first to see how it behaves."  Admittedly, system qualification
    and customer's configurations are not always "sensible".  
    
    Regards
    
    Greg