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Conference azur::mcc

Title:DECmcc user notes file. Does not replace IPMT.
Notice:Use IPMT for problems. Newsletter location in note 6187
Moderator:TAEC::BEROUD
Created:Mon Aug 21 1989
Last Modified:Wed Jun 04 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:6497
Total number of notes:27359

1656.0. "Vitalink Bridge TEST problem!!" by SMAC10::DAVIES () Tue Oct 15 1991 13:14

I entered the following note in the Vitalink notes file but could be DECMCC
problem. Any comments!!!


			John Davies
			EIS,Bristol
			

          <<< IAMOK::$1$DUA72:[NOTES$LIBRARY]VITALINK_BRIDGE.NOTE;1 >>>
                             -< Vitalink Bridges >-
================================================================================
Note 510.0                    Loopback from DECMCC                       1 reply
SMAC10::DAVIES                                       25 lines  14-OCT-1991 11:18
--------------------------------------------------------------------------------
    I have a customer with a translan III with version 6.10.2 software.
    Linked across a number of 64k lines are more vitalink bridges some
    using v10.4.2 others using version 6.9.7. 
    
    
               DECMCC   Translan---------------------Translan
    			V6.10.2 ---|                  V6.9.7
                  |      |         |
    	|-------------------|      |                  Translan
    				   |----------------- V6.10.2
    
    
    Using DECMCC it is possible to use the TEST command to send a loopback 
    message to each of the Translans 
    e.g. "Test station Vitalink" will send an Ethernet or DEC_enetv2 loopback
    to the bridge. This works ok for the local bridge (10.4.2) and also for
    the remote bridges over the 64k lines (V6.9.7) However any remote
    bridges with version 6.10.2 software will not respond to the loopback.
    
    Anyone got any ideas why this should be?? Configuration problem, timing
    problem??
                                         
    
    		John Davies
    		EIS, Bristol
================================================================================
Note 510.1                    Loopback from DECMCC                        1 of 1
TOOK::MCPHERSON "i'm only 5 foot one..."             26 lines  14-OCT-1991 13:35
                          -< Might ask in NOTED::MCC >-
--------------------------------------------------------------------------------
re: <<< Note 510.0 by SMAC10::DAVIES >>>

>    Using DECMCC it is possible to use the TEST command to send a loopback 
>    message to each of the Translans 
>    e.g. "Test station Vitalink" will send an Ethernet or DEC_enetv2 loopback
>    to the bridge. This works ok for the local bridge (10.4.2) and also for
>    the remote bridges over the 64k lines (V6.9.7) However any remote
>    bridges with version 6.10.2 software will not respond to the loopback.
>    
>    Anyone got any ideas why this should be?? Configuration problem, timing
>    problem??

I'm surprised that something would work with 6.9.7  and not 6.10.2.....  Oh
well.   Might be a timeout problem, but hard to tell.  Is the 6.9.7 Translan
less loaded than the 10.4.2 Translan?    

FWIW: I just tested against 2 Translans running 10.4.2 here (on loan for
Translan AM testing) and I can't get the remote Translan to answer to a STATION
TEST.    It still returns the other station attributes when I speak to it as a
station, but the TEST directive bombs with a "Cannot communicate with target".

You may want to post this in the MCC conference (NOTED::MCC) , if you already
haven't.   Maybe someone from the ethernet_am team will pick up and give some
clues...

/doug
T.RTitleUserPersonal
Name
DateLines
1656.1Broken on purpose. Want it fixed?TOOK::MCPHERSONi&#039;m only 5 foot one...Wed Oct 30 1991 17:42196
Well, 

Vitalink maintains that they removed support for remote Translans responding to
the TEST directive on purpose.   I have gone a couple of rounds with Vitalink
about this.  The story they're giving me now is that "... it was illegal for
a sync line on a LAN Bridge to respond to a LOOP..."

FYI: Correspondence attached, if you're interested...

I have questioned this rather vigorously, and am awaiting response.


From:	US1RMC::"[email protected]" "Bill Wood" 24-OCT-1991 19:32:06.08
To:	took::mcpherson
CC:	
Subj:	Re:  Has something changed in the MOP implementation on Translans between 6.9 and 6.10 ?


I recevied your message this a.m., since then, I had a couple of people looking
into this question. Here's the answer...

As per my cohort, Brian Pierce, Bridging Product Specialist:

	What you are seeing is to be expected, what we did in the old version
	of the s/w was illegal.  We are now legal by not responding to the
	request across a serial link. We will only respond locally.

I hope this answers the question, it may not be the answer you wanted...

hope I helped...

billw

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
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% Received: by uucp-gw-1.pa.dec.com; id AA13167; Thu, 24 Oct 91 16:18:17 -0700
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% Date: Thu, 24 Oct 91 15:53:00 -0700
% From: [email protected] (Bill Wood)
% Message-Id: <[email protected]>
% To: took::mcpherson
% Subject: Re:  Has something changed in the MOP implementation on Translans between 6.9 and 6.10 ?

From:	US1RMC::"[email protected]" "Bill Wood" 25-OCT-1991 13:43:16.97
To:	took::mcpherson
CC:	[email protected], [email protected]
Subj:	Re:  Has something changed in the MOP implementation on Translans between 6.9 and 6.10 ?


i received your message of :

----- Begin Included Message -----
>
>As per my cohort, Brian Pierce, Bridging Product Specialist:
>
>	What you are seeing is to be expected, what we did in the old version
>	of the s/w was illegal.  We are now legal by not responding to the
>	request across a serial link. We will only respond locally.
>
>I hope this answers the question, it may not be the answer you wanted...
>

Well this begs the question: 
                "*Why* is this illegal?"  

If it's an "802 WAN" , then why not implement the 802 protocols (including
TEST) across it, including serial links?

I suppose I can accept the answer if I could get a better explanation of the
rationale for intentionally disabling this feature...

/doug


----- End Included Message -----

I am having Brian take a look with Engineering, he said something about a
document containing this information.

unfortunately, it may not be until next tuesday before i have an answer for
you, i hope this will be able to live until then.

'til next tuesday...
have a good weekend...

billw

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% Date: Fri, 25 Oct 91 09:40:19 -0700
% From: [email protected] (Bill Wood)
% Message-Id: <[email protected]>
% To: took::mcpherson
% Subject: Re:  Has something changed in the MOP implementation on Translans between 6.9 and 6.10 ?
% Cc: [email protected], [email protected]

From:	US1RMC::"[email protected]" "Bill Wood" 30-OCT-1991 16:58:54.20
To:	took::mcpherson
CC:	[email protected]
Subj:	Re:  Has something changed in the MOP implementation on Translans between 6.9 and 6.10 ?

in your msg from last week...

----- Begin Included Message -----
Well this begs the question: 
                "*Why* is this illegal?"  

If it's an "802 WAN" , then why not implement the 802 protocols (including
TEST) across it, including serial links?

I suppose I can accept the answer if I could get a better explanation of the
rationale for intentionally disabling this feature...

/doug


----- End Included Message -----


well...   according to the document "The Ethernet", "A Local Area Network",
"Data Link Layer and Physical Layer Specifications", Version 2.0 November 1982,
Section 8. Ethernet Configuration Testing Protocol. The Ethernet Configuration
Testing Protocol provides a minimum testing capibility of communication between
stations on an Ethernet.  It is the only Client Layer protocol specified in
this document and has the only  assigned Ethernet type field value in this
document.  All Ethernet stations must support the configuration testing
functions.

Our engineering staff interprets this to mean that the test packet will only
apply to the local port, not the remote port.

my own opinion: it seems as though we are trying to, at a minimum, meet the
specification.  whether or not we should have deleted this "feature", I can not
judge.

I hope this answers the quetion?

billw

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% Date: Wed, 30 Oct 91 10:22:46 -0800
% From: [email protected] (Bill Wood)
% Message-Id: <[email protected]>
% To: took::mcpherson
% Subject: Re:  Has something changed in the MOP implementation on Translans between 6.9 and 6.10 ?
% Cc: [email protected]

From:	TOOK::MCPHERSON "Doug McPherson | DTN 226-5145 | LKG2-2/N1  30-Oct-1991 1709" 30-OCT-1991 17:35:00.96
To:	US1RMC::"[email protected]"
CC:	MCPHERSON
Subj:	Re:  Has something changed in the MOP implementation on Translans between 6.9 and 6.10 ?

Bill, 

Standards are (to some degree) open to interpretation.  I can live with a
vendor reading a standards document, then implementing it differently from
another vendor (who has purportedly implemented the _same_ standards...)  Such
is life in the world of standards.

I *do* however have some heartburn when a vendor implements their
interpretation of standard, then later (almost capriciously) changes it as part
of an "enhancement", leaving the customer with *less* functionality than
before!

Translan bridges themselves (in that they use leased, relatively low-bandwidth
wide area network connections over serial lines) violate some very BASIC
assumptions that 802.3 networks (and associated LAN protocol stacks) are built
upon:   
        - high-bandwidth  
        - extremely low error rates 
        - limited geographic extent (propagation delays)

That being the case, I find it _extremely_ difficult to believe that Vitalink
would all of a sudden take the time and effort to DISABLE a (very useful, and
_working_) feature in the name of 'minimal adherance to a standard'.    

If the purpose of a Translan Bridge is to create an extended (802.3) LAN, then
each Translan, as a legitimate member of that LAN should implement respond to
the "LOOP" (or TEST) directive, disrespective of its geographic location (i.e.
whether or not it's on the local or remote side of a serial line).   Prior to
6.10, Translan bridges *did* participate in this manner.

Please consider this a formal request to "re-enable" the "TEST" feature over
serial links.   If there is an appropriate channel that I need to use, please
point me to it. 

/doug
1656.2MerciSMAC10::DAVIESSun Nov 10 1991 11:074
    Thanks for the input. Hope the feedback gets to Vitalink and they re
    implement this feature.
    
    		John Davies