Xref: utzoo comp.protocols.iso:212 comp.std.internat:448 comp.dcom.lans:2316
Path: utzoo!attcan!uunet!husc6!encore!cloud9!jjmhome!cpoint!martillo
From: martillo@cpoint.UUCP (Joacim Martillo)
Newsgroups: comp.protocols.iso,comp.std.internat,comp.dcom.lans
Subject: Layer Encapsulation in OSI
Message-ID: <2016@cpoint.UUCP>
Date: 27 Jan 89 11:30:50 GMT
Reply-To: martillo@cpoint.UUCP (Joacim Martillo)
Organization: Clearpoint Research Corp., Hopkinton Mass.
Lines: 19

Anyone know of any references to layer encapsulation in official
OSI or CCITT documents.  The problem is as follows:

LLC type II is reliable and one might want to provide security
on a per logical link basis,  Unless you want to provide reliability
in the security layer itself, to make sure that applications which
run in a secure environment, you want to put the security layer
between LLC and the MAC layer, but at that point in the stack
the protocol software should only be looking at the MAC addresses
and security cannot be provided on a per logical link basis.
And if the security layers lives at the top of LLC, then the
security layer has to provide reliability.  

I vaguely remember having this problem at Bell Labs when working
on Data Teleconferencing and the solution was layer encapsulation
where the security procedures would encapsulate the protocol
layer, but I simply don't remember where this was described in
the CCITT or OSI documents.  If someone could give a pointer,
I would be grateful.