Subject: Last call on draft-ietf-pppext-aal5-03.txt

From: James Watt <[email-masked]>
Date: Mon, 1 Dec 1997 19:27:38 -0500

Folks:
  I know we have been around this a few times but I'm afraid the
text we have in Section 4 may cause interoperability problems.

Point (3) says:

     3. If an implementation is connecting though a Frame Relay/ATM
     FRF.8 [7] service inter-working unit to an RFC 1973 [6] end point,
     then it MUST support LLC encapsulated PPP payloads.

However, only the customer knows if this is true; the device
certainly doesn't.  Thus, for interoperability it would seem I
would have to assume this is always true.

However, point (2) says:

     2.  MAY use LLC encapsulated PPP payloads on PVCs as described in
     section 6 below by mutual configuration or negotiation of both end
     points.  This technique is referred to as "LLC encapsulated PPP".

Normally, point (2) would lead me to assume this is an optional
capability.  However, given that only the customer can tell if point (3)
applies, point (3) suggests such support is mandatory.

If it is mandatory, then we should say so, i.e. collapse points (2) and (3)
into one and say "it MUST ... in case the connection traverses..."

Comments ?
-james

____________________________________________________________________________
James W. Watt,	[email-masked]		 Ph:  (613) 591-3600
Newbridge Networks	600 March Rd Kanata ON Canada K2K 2E6	 FAX: (613)
591-3680

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From: Philip Rakity <[email-masked]>
Date: Tue, 2 Dec 1997 14:27:22 -0800 (PST)

James,

I think the idea is that if I want to use LLC encapsulation between two
devices I am free to do so if I am NOT doing Frame Relay interworking
(point 2).

Point 3 say if I am doing FRAME relay interworking then I must use LLC
encapsulation.

It is true that only the customer`s know.  Both the local and remote
systems using AAL5 must be compatibly configured.

regards,

Philip Rakity
FlowPoint

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From: James Watt <[email-masked]>
Date: Wed, 3 Dec 1997 00:39:00 -0500

>devices I am free to do so if I am NOT doing Frame Relay interworking
+--------
I thought that was what we agreed to.  However the text says
"MUST support", not "MUST use".
>systems using AAL5 must be compatibly configured.
+--------
Agreed.  Perhaps all I'm hung up on is "implementation ... MUST support"
vs "implementation ... MUST use", i.e. all implementations must be capable
of doing both but points (1) through (3) control which method they use
in various cases ?

Thanks
-james

+--------

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From: "Andrew G. Malis" <[email-masked]>
Date: Thu, 4 Dec 1997 10:10:58 -0500 (EST)

James,

The intent was that implementations may, but are not required, to
support LLC encapsulation.  However, going through an FRF.8 service
interworking unit requires the use of LLC encapsulation.  Thus, only
implementations that support LLC encapsulation may utilize service
interworking.  Since service interworking is (at least currently) for
PVCs only, this all has to be configured manually. 

In point 3, changing "MUST support" to "MUST use" is fine with me.

Cheers,
Andy