Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!sharkey!cfctech!teemc!mibte!gamma!thumper!faline!nvuxr.cc.bellcore.com!ak2
From: ak2@nvuxr.cc.bellcore.com (Arthur Knapp)
Newsgroups: comp.protocols.iso
Subject: Re: question on OSI addressing
Message-ID: <2328@faline.bellcore.com>
Date: 28 Nov 89 20:19:46 GMT
References: <4633@swift.cs.tcd.ie>
Sender: news@faline.bellcore.com
Organization: Bellcore
Lines: 26

In OSI naming & addressing & registration authorities, there is no such 
thing as a simple question! 
 
You are correct about needing an application-context and 
presentation-address to establish an association between application-entities.  

Selectors are chosen by the local systems administrator.  The called party tells the calling party what the called systems address is.  When provided with the (OSI X.500 Directory) distinguished name of an application-entity (aka application-entity-title), the OSI directory will provide the 
presentation-address as a tuple  {  presentation-selector, 
session-selector, transport-selector, list of Network-Addresses  }.  The 
DLSAP and subnetwork point of attachment (SNPA) addresses are of no 
concern to OSI applications, i.e., let the network, data link and physical 
layers do whatever they have to in order to get the job done.  

Connection endpoint identifiers (CEIs) are local and are not addresses, 
are not part of an address, and are not part of the directory.  CEIs are 
dynamically assigned.  

If you don't use the Directory, then you have to use magic.  You write 
these addresses down on the back of an envelope and have them entered into 
a table.

Arthur Knapp          ak2@nvuxr.cc.bellcore.com
Tel: 201-758-2198           Fax: 201-530-6875
331 Newman Springs Road, Rm 1F-359
Red Bank, NJ 07701-7020  USA
Telex: 275318


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