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Conference noted::decnis

Title: DEC Network Integration Server (DECNIS)
Notice:Please read note 1 to use this conference effectively
Moderator:MARVIN::WELCH
Created:Wed Sep 18 1991
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3660
Total number of notes:15082

3575.0. "ncl for second LLC2 link" by CHEFS::DAVIES_J () Tue Mar 18 1997 12:09

	I also put this in the x25_osf notes file

	---------------------------------

    I would appreciate a little guidance as how to set up multiple LLC2
    links between a DUNIX machine and one DECNIS.
    	The first LLC2 link is fine and I have set this up ok. Reading
    through this notes file(X25_OSF) indicates that creating a second LLC2 link
    between the same two nodes is also possible using different LSAPs.
    
    Exactly how does this work?
    
    First LLC2 link
    
    create llc2
    create llc2 sap sap-0
    set llc2 sap sap-0 station csma-cd station csmacd-1 local lsap address
    7e
    create llc2 sap sap-0 link link-0
    set llc2 sap sap-0 link link-0 remote mac address aa-00-04-00-22-f8,
    remote lsap address 7e
    
    The sap sap-0 is associated with the csmacd station ie the ethernet
    port and has a local lsap of 7e.
    
    Exactly what is the syntax for creating another llc2 sap link using
    another LSAP. It seems to be rather illogical wherby the local lsap is
    associated with the sap but the remote lsap is associated with the sap
    link.
    I dont have the luxury of trying this in the office so would appreciate
    any help
    
    
    	Regards
    
    	John Davies
    
    	
    
    
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3575.1Cut 'n' paste?MARVIN::CARLINIWed Mar 19 1997 05:4027
>    Exactly what is the syntax for creating another llc2 sap link using
>    another LSAP. It seems to be rather illogical wherby the local lsap is
>    associated with the sap but the remote lsap is associated with the sap
>    link.

The local SAP is your SAP, i.e. the SAP you use to identify your transmissions;
if you have multiple links (to different destination machines) your SAP is
always the same, but each link needs to know the SAP that the remote machine
uses to identify itself, hence the remote LSAP belongs to the link.

I've done this with VMS hosts talking to VMS hosts and with VMS hosts talking to
DECnis boxes. In both cases I think I could just choose the new SAP values and
use the configurators (i.e. SAP 7E talks to SAP 7E, SAP 7C talks to SAP 7C etc.)
but with DUnix you may have to do it by hand. In that case, configure your first
link as you have done and then copy the SAP and SAP LINK creation and setting,
changing the names and the SAPs.

Remember that you only get to use every other SAP i.e. you can use 7E but you
cannot use 7F (since the bit in question is the difference between a command and
a response).

The other (almost) gotcha is that strictly speaking the non-7E SAPs belong to
the ITU which could at any time mandate that SAP 7C is to be used for some new
purpose. So beware - you need to know what else is going on on the wire
(although at the moment, in practical terms, there is nothing to worry about).

Antonio
3575.2thanksCHEFS::DAVIES_JWed Mar 19 1997 07:296
    Many thanks for that. I have  in fact managed to get hold of a decnis
    and a VMS system and configured a number of LLC2 links.
    
    	Thanks
    
    	John Davies